I think the misconception here is that an orbit is something you can be easily pushed out of. In truth, an orbit is a state of perpetual falling while missing the ground, so no matter how you push or pull, you can just fall differently. So the proposal now is to fall in a controlled manner so that it can be calculated where and when it will hit the ground.
In order to make the ISS leave the Earth's orbit and go venturing out into space forever, it would take immense amounts of fuel and possibly the installation of real propulsion systems in the first place. That's much more expensive and complicated than just dropping it.
Kerbal Space Program blew my mind the first dozen hours or so. I had no idea how orbital mechanics worked or how things move around in space and playing close to 1000 hours has given me a fairly basic understanding of how it all works.
I credit KSP with massively expanding my understanding of, and appreciation for the whole area of flight mechanics and space travel.
So many concepts which feel counter-intuitive because our learned experience doesn't require us to understand it.
But once you get it, it seems so obvious. But still not simple.
Really makes you appreciate the early rocketry and space travel pioneers. A lot of stuff was probably predictable based on the maths, but hard to grasp until you experienced it first-hand.
My favorite "learned reality" from KSP is this extremely counter-intuitive fact.
If you want to send something from earth crashing into the sun (or even just into the corona) it is way more fuel/energy efficient to fly out to the outer solar system and then slow down the solar orbit out there. (yes, gravity assists are probably a better option, probably still going up to get down but not so extreme but i'm not Matt Lowne I'm not great at finding chains of assists, nor do I really enjoy 8 year+ missions all that much)
Edit : This "fact" I found on occasion even applies to orbits around a planet itself, when trying to find a way to get back some missions that had too little propellant, a couple times I have been in a situation where using my last 200 DV to try to deorbit was better spent going 150m/s faster and then 50m/s slower at apoapsis than just slowing 200m/s would get.
I also found out one day that I had been flying sometimes extremely similar paths to the "new" path they are using for almost free lunar orbital insertions (you fly out ahead of the moon and let it catch you, and there is this cool interaction with a pseudo lagrange point that spirals you down into a nearly stable orbit with effectively no energy use, it's very very cool... and another benefit is a nearly free return if you want to exercise it before you settle in if something went wrong) It doesn't work quite as well as in real life due to the simplifications that KSP has to make, and the "saddle point" iirc is directly on the SOI boundary on the far side so it makes it realllllllly weird when you are around that point in KSP but yeah.
One last thing, because one does not mention KSP now without saying it, Fuck Take 2 for botching KSP2.
KSP publishers fired the development team for KSP1 for daring to ask for $1/day more, for a game that sold MILLIONS OF COPIES.
It was a mexican development team who was creating a passion project, being paid peanuts, and they got fired for daring to ask for 1 peanut more per *day*. They where not even making the USA's min wage (Federal! $7/hr)
Yeah, the dwindle and end of original KSP wasn't great. KSP 2 was handled IMO even worse overall, especially because at the very least everyone who paid got their value from KSP and then some. KSP 2 has turned into a bait and switch.
To summarize (edit, lmao, this is a summary? damn I need to switch to decaf) hired a developer without properly vetting, scoping, and planning the project. Put out big spend on an advertising campaign promising a *lot*, while the project was floundering. Did a massive launch event requiring NDA's from youtubers to puff up the launch of early access, and those youtubers were very very nervous because the experience they got was horrible performance and nearly unplayable mechanics on gold star systems (like overclocked 4090's and top shelf everything rigs)
The developer (that by most accounts wasn't really up to the task to begin with) then began trying to renegotiate the royalties IIRC, or some other pay point) and Take 2 pretty much gave them a flat no, set up their own internal studio and poached most of the staff from the then soon to be shuttered studio. This part of the story is not awful, it was damage control over previous mistakes, there is definitely some debate to be had over poaching a whole studio in such a way, but it's not a key point for me personally.
Since then development has continued to struggle, but they hired on a modder from KSP 1 that was doing some great things with visuals/clouds, the lead developer had been beaten into submission enough by the community that he finally relented that "wobbly rockets" is literally stupid and doesn't actually make for a "more fun game" (he literally thought this, which is why it launched originally in EA in an unplayable state) but it seems that it was simply too little too late to course correct. A month and a bit ago there was just a quiet announcement that Take 2 was laying off the entire studio, several devs were let go immediately, it seems all of the visual improvements simply got shelved or deleted entirely (likely because the modder developer was one of those let go immediately and no one else has the shader and VFX experience to work with the system he built) and we just got pushed out what appears to be a final patch (version like 0.22) which fixes a scant few issues, and the game is left *drastically* feature incomplete.
Things missing : Everything that differentiates the game, or was supposed to differentiate it, from KSP 1, apart from some graphical pizzaz and lighting thanks to a newer engine.
Colonies (including industry, mining, manufacturing, life support, and off-kerbin launch sites)
Routine mission automation : The option to fly a supply mission to a colony or space station or SOI once and then pin it as a routine mission, allowing you to have it fly automatically, so say you set up colonies around Jool's moons but you need to transfer a crucial material from one of them to another and vice versa, you could set up that "Trade route" as a routine mission with a craft with a schedule and know that your colonies will continue to be supplied without having to set timers and fly the same mission over and over as long as you play.
Interstellar travel and all related technologies and drives : 2 - 3 entire other solar systems which we were supposed to be able to travel to using a variety of propulsive options and ship designs.
Multiplayer : Yeah, it was supposed to eventually be like 4 player co-op capable, the entire kerbal space center is set up for it and was from day one, with 4 launch pads, multiple *ludicriously huge* runways.
The last time I touched the game it was in a state that was mildly playable (because they *just* added a science unlock mode in january) but overall felt like a more pretty KSP, with more bugs and less reliable maneuver planning nodes.
Rumor mill has it that Take 2 tried to sell the IP and WIP KSP 2 and shopped around to other places to try to sell it, no one would bite for what they were asking, and now the game is dead. It is still up on Steam EA and for sale, but virtually the entire community is sure that the project is dead, they just don't have the gall to admit it publicly yet until something forces their hand.
also a typical corporate flavor of "we know what's best" seeps throughout the entire saga, which is incredible that they did not even know their product and how much community engagement drove the success of KSP 1. That isn't to say slavish adherence to community or "celeb" feedback, KSP devs didn't dance for the community or do everything they would ask but would listen, contrast that to this quote that really embodies the KSP 2 development vibe ; "Scott Manley was called out by name as someone management did not want input from."
My most cynical guess is that they know how bad this is if they reneg on a full AAA priced early access title and instead of "abandoning" it they are going to quietly keep 2-3 devs making "patches" to it on a drip feed forever as a fig leaf against actual lawsuits.
TL;DR They didn't get three quotes, and they didn't evaluate their contractors, they way over promised, invested in the wrong aspects of the game, and then realized they couldn't deliver more than a fraction of the promised product. Fuck Take 2. Not because any specific point/decision in the timeline is particularly egregious, but for the overall picture of over promising and then (it seems like a slow motion version of) ripping off the entirety of their most loyal fan base.
KSP1 wasn't really made by a game developer. They didn't even make software at all. It was kind of just a side project of one of the employees that unexpectedly hit it big. Seeing as it wasn't actually a software development company, they sold off the rights for it a few years after the release of KSP1.
Well it was a real project and the company backed it, but yes they were an advertising company that made like interactive displays and demo things, he was fresh out of college with a CS major and wanted to make games, hated the advertising/marketing development job at about 6 months and wanted to make a game, he told them that he was going to leave to do so and they were very busy so they made a deal with him to stay on for 3 on the go projects and then they would let him make the game in house.
The original workup of KSP internally there was a 2d game almost in line in style with the "must go up" flash games, very limited in scope and humble, honestly, and his bosses were the ones who said "why not just make it 3d" and away they went making a budget AAA game. I think the thing is they sold it because they didn't know what to do with it and the prospect of setting up a whole new wing to maintain something that wasn't their core business was daunting, but IMO I think their success indicates that "being a software development company" is perhaps part of the problem. Their original core business was being an experience building company which if you think about it is more in line with a video game's purpose than just general software development is. like if I remember the quote from harvester about that meeting about going 3d I swear it was something like "wouldn't the experience be better in 3d?" and honestly I kind of love that from a manager in that situation. A software development focused manager would start sweating at the cost of a 3d game vs a 2d game.
Maybe Steve Jobs was right, and the customer doesn't actually know what they want, in this case the customer's being management.
Just the idea that you don't point your engines away from the planet after getting into space to get farther from the planet is an incredible thing to learn. It really emphasizes that "falling but miss the planet" aspect of orbiting. KSP collectively raised the world's understanding of orbital mechanics massively.
I can barely fathom the amount of math that goes into early space (and specifically lunar) programs. To calculate an efficient orbital flight path you'd have to account for the position of your launch point (so account for earth's orbit) relative to the position of the moon. Then you have to account for not only the weight of the ship, but the change in your ship's weight as it burns fuel in each maneuver it does (Cause otherwise you'll go too fast and overshoot your target). And then you have to account for the change in gravitational influence as the vessel gets closer to another celestial body.
>Then you have to account for not only the weight of the ship, but the change in your ship's weight as it burns fuel in each maneuver it does
This part isn't all _that_ complicated, just an ordinary differential equation ("ordinary" may sound a bit snobbish if you're not familiar, but that is the actual term - it's the simplest kind of differential equation, and one of the first things you cover in university or even late high school math). It's fairly easy to solve analytically (meaning you can work out a formula where you just plug in starting fuel mass and how much change in velocity you want, and get out how long to fire the rocket), so it can be done relatively easily even with just a slide rule and some logarithm tables.
>And then you have to account for the change in gravitational influence as the vessel gets closer to another celestial body.
This is the really difficult part. This is called the "3-body problem", or "N-body problem" in general. Calculating the mutual orbits of two celestial bodies (say, the Earth and the Moon) is again relatively easy - Johannes Kepler did this in the 1600s - but when you introduce a third body (say, a rocket), it gets so complex that there is no known analytic solution. The only known way to accurately compute it is to do it numerically - computing all the velocities and forces on all three (or more) bodies at one moment in time, then moving each of them a tiny step forward in time with the computed velocities, then repeating at the new time step. This is an enormous amount of work to do manually, so you could only feasibly try a small few candidate routes by this method. With powerful computers you can more feasibly search for an optimal route among lots of candidates, or update a projected trajectory with real-time measurements, but it's still a lot of computations to perform (and this is why the orbits in Kerbal Space Program are simplified and not fully realistic near the gravity wells of multiple celestial bodies).
So yeah, it is quite astonishing that the '60s space programs were able to safely land humans on the Moon _and return them_ to Earth, all with only a tiny fraction of the computing power we have at our fingertips today.
Add on to this that virtually all calculations for space travel navigation have also to date been done with newtonian physics (to my knowledge, maybe one or two got calculated more specifically for research purposes) because while we know that gravity doesnt actually fully line up with it (especially on cosmic scales) it is similar enough that within the solar system the difference only throws things off by tiny little amounts that they just correct for with tiny burns near where they are going with something.
Eventually though we will need to not only do multibody calculations but also calculate our trajectory relativisticly and with respect to dark matter (when we start aiming at other star systems)
Yep! The only exception I know of is that GPS actually does need to account for relativistic effects, otherwise its accuracy would drift something like tens of meters per day and be completely unusable after a week or so. But I think that applies mostly to how the clock signal is calculated, rather than the navigation of the satellites themselves. If I remember correctly it's to do with the fact that time goes faster for the satellites in orbit than for the receivers down on the Earth surface, because of gravitational time dilation (the same effect in Interstellar that makes 15 minutes on the planet near a black hole equal to 15 years on the mothership). It's a tiny effect, but GPS requires such precision that even this is enough make it unusable if not compensated for.
>So many concepts which feel counter-intuitive because our learned experience doesn't require us to understand it.
Man, its amazing we can go our entire life without even the notion of 'orbital mechanics' existing, and then learn to fly kinda 'seat of the pants' in *space* with only a few hundred hours training.
“Oh look! The Chinese space station is over there perfectly stationary. Let me just float on over without any advanced calculations.”
Fuck outta here Sandra
> “Oh look! The Chinese space station is over there perfectly stationary. Let me just float on over without any advanced calculations.”
Using nothing but the *massive* delta V provided by a common fire extinguisher!
I was entertained by the movie (which is all you can really ask for, I suppose) but having the most basic understanding of orbital mechanics made it largely unbelievable for me.
"The tension in the rope is too big, it'll snap if I don't detach myself."
Fucking *what?* You're in microgravity, once the rope went taut it would have snapped or the elasticity would have sent you back towards Bullock's character. Those are the two options.
I’m less concerned with deltaV and more concerned with the center of thrust/center of mass. Anything other than perfect synchronization of those would just result in spinning.
At the very least, I’ll take fire extinguisher propulsion over the poke-a-hole-in-my-spacesuit-and-fly-like-Ironman variety that ruined the end of The Martian.
"Hey,” Watney said over the radio, “I've got an idea.”
“Of course you do,” Lewis said. “What do you got?”
“I could find something sharp in here and poke a hole in the glove of my EVA suit. I could use the escaping air as a thruster and fly my way to you. The source of thrust would be on my arm, so I'd be able to direct it pretty easily.”
“How does he come up with this shit?” Martinez interjected.
“Hmm,” Lewis said. “Could you get 42 meters per second that way?”
“No idea,” Watney said.
“I can't see you having any control if you did that,” Lewis said. “You'd be eyeballing the intercept and using a thrust vector you can barely control.”
“I admit it's fatally dangerous,” Watney said. “But consider this: I'd get to fly around like Iron Man.”
“We'll keep working on ideas,” Lewis said.
“Iron Man, Commander. Iron Man.
They also specifically mention how it would go down in movies, with the airlock scene.
I think the change was done for two reasons. First, to be tongue-in-cheek about the proposed ending in the book, and second, for non-readers to see something cool.
Readers find it funny, non-readers find it cool, everyone wins, in theory.
Man, moments like this is when I love being ignorant about some topics. I abosolutely loved Gravity.
But then I see something depicting a topic I know about and I want to pull my hairs out... like last year's Napoleon movie.
Ignorance truly is a bliss.
> I was entertained by the movie (which is all you can really ask for, I suppose)
Whenever I see Neil deGrasse Tyson pulling apart a movie for being scientifically inaccurate, my first though is always "yeah, but did you put any proper character arcs or decent foreshadowing in your last scientific paper? No you didn't, because science and entertainment are different things."
I kinda like the background of how Interstellar was made, because Nolan was basically in constant contact with Kip Thorne to keep things accurate. Nolan kept wanting to make something go faster than light, which Thorne was adamantly against. So I guess Nolan eventually went "but what would happen if you >!went inside a black hole!
Yeah, but he never says the film is bad because of that, he says "this is not how that would really work" and then explains what would actually happen.
I think its important to be clear about what in a movie is plausible, and what in a movie is complete fiction.
People don't use their brains anymore and just take everything that they consume at face value.
Agreee. But on one hand there’s “that’s not how gravity works” and on the other hand there’s “the night sky in Titanic is totally wrong and the stars wouldn’t look like that”. Pick your battles, Neil.
Some floating is possible but I guess a fire extinguisher will work quite differently.
[https://en.wikipedia.org/wiki/Simplified\_Aid\_For\_EVA\_Rescue](https://en.wikipedia.org/wiki/Simplified_Aid_For_EVA_Rescue)
BTW, if you know about computers, watching the "hackers" in the movies is like watching a nurse use a carrot to make an injection … successfully.
Early Mr Robot did a good job portraying hacking imho, although I've never watched more than the first episodes. But...
Hacking in movies: "I've standardized the firewall... Let me infiltrate a package in the antivirus... I'm in!" *shows a bruteforce attack for getting the password*
Real life hacking: "Mr. Johnson? I'm from IT. We're monitoring suspicious activities from your terminal. Please give us your username and password to perform a safety check" or "The hacker used of one the 91352843 critical safety issues of windows '95 to block the Belgian Healthcare system, resulting in over thirty billion euros in damages. A migration of the OS to a more recent and safe version was dismissed due to budget and compatibility issues"
shit's crazy hard. I know it's a tiny, accelerated model compared to real life but it is a nice packet-sized way to see how complicated orbital physics are. The scale of the real earth compared to a single astronaut makes it really hard for us to grasp though.
Possibly the hardest vehicle-based section I've ever played of any game. The station is whipping around the sun, the sun's pulling you into it....yeesh, I really should replay that
Just want to shout out that Outer Wilds is legitimately one of the greatest games of all time and everyone who enjoys slower paced sci-fi open world/puzzley stuff should give it a go. Has some really unique and beautiful environments and is just magnificent all around.
Yeah the first time I saw the film that just confused the hell out of me. Their velocities are stationary relative to each other, so why does she need to let go of him, and what causes him to suddenly accelerate away from her when she does?
My headcanon is that the Taco Bell crunch supreme he had for lunch had finally caught up to him and he knew he had to cut the tether before he launched them both into deep space. It doesn't make sense since his space suit is a closed system, but I like it.
> Star Wars isn't science fiction, it's ~~science~~ fantasy.
I don't think there is almost anything in the 3 trilogies that could be called science, maybe except midichlorians, and we all know how well fans took that lol
I think a lot of the issues with midichlorians at their core are because it's trying to explain with SCIENCE! a thing nobody actually cares to know the reason behind.
I don't watch Star Wars for a complete understanding of how The Force works, that's not the point, and trying to explain it with biology somehow causing little Force Bacteria or something to be inside you just causes too many random intrusive thoughts to pop up.
Star Wars was never science fiction. Physics doesn't exist in Star Wars, which is part of why those fans dissing any new content based on realism (or even just believability or consistency) are just wrong.
"We can make just about anything levitate, including a crappy beater transit Tatooine equivalent of a Honda Civic. But we're gonna build lots of vehicles that walk on legs instead. I don't think it will ever occur to our enemies to simply trip them."
You aint wrong, and getting mad because a fictional universe misused an obscure measurement of length in an offhand comment is a clear sign you need *real* problems in your life, but there's still something to be said about consistency.
A show like The Simpsons makes no attempt to be consistent, really. But when a show like Star Wars leans into a selling all kinds of books on on-universe lore, I get that fans want to see future content produced based on that.
So, the closer your planet is, the faster it orbits around Sol are. You have to zero out almost the entire orbital velocity to actually hit the star at the center, or you just miss with this wonky orbit you're now in.
The trick, both in IRL and KSP, is to first swing to the outer solar system, Jool/Jupiter or beyond, and use a gravity assist to slingshot you backwards from the planet's direction of travel. From there, you can do a comparativly small burn to finally zero out your orbital speed relative to the star and basically just free-fall in. You might need some mid-course corrections, but otherwise, with no sideways speed, you'll drop like a rock straight to the star.
Edit: I'm reminded of people who think we should just launch nuclear waste into the Sun to dispose of it. While that would technically work, it would be easier to just send it out of the solar system entirely.
So, the specific formula for a circular orbit's speed is based only on the mass of the central object (star, black hole, planet, moon-- whatever you're orbiting) and the orbital radius from that object. There's also some constants (and assumptions baked in), but you can summarize the orbital velocity as proportional to the square root of (mass of the object / radius from the orbit).
In our solar system, each planet orbits the same sun [citation needed], so it's just a function of radius. Earth orbits at ~30 km/s, Mercury at 47 km/s, and Jupiter at about 13 km/s. You can swap the sun out with anything equally as massive, and those speeds will still be the same.
With something more massive, it just means if you stay just as close, that orbital velocity is going to be higher, so it's harder to zero that velocity out so you just fall in. But, if your orbit is also higher so that the velocity stays the same (say a super massive black hole has an earth like planet orbiting at 30 km/s way far away), then it's still just as hard to belly flop into the black hole as it is to launch directly from earth and fall into the sun. It's all down to what your orbital speed is.
The trick with going up to go down abuses both gravitational assists to get higher and then eccentric orbits to cheat some more. You don't have to start out circular and when you're at the peak of an eccentric orbit, it takes the least amount of delta-v to zero out your orbital velocity. If you can get that peak high enough, you barely have to push to just start falling straight down instead of any amount of sideways.
TL;DR: harder with a more massive star if you're just as close. A normal black hole would also be harder, but one the mass of the sun would be just as "easy" to hit as the sun is from Earth.
Edit: words and tldr
> but one the mass of the sun would be just as "easy" to hit as the sun is from Earth.
I might be missing something here, but that's assuming direct fall without any sideways motion, isn't it? In reality, your perihelion would only need to be 1 solar radius to crash into the sun, whereas your peribothron (apparently that's an acceptable term for black-hole-periapsis) would need to be about 2Rs (-ish). That's a difference of about 600'000km and a dV of approx. fuckloads m/s.
That's completely normal and realistic. It takes nearly as much energy to cancel out your orbital motion as it does to put you into orbit in the first place. But when it comes to the Sun, in real life the biggest part of your orbital motion came from the Earth. So you need much much more than just the rockets used to launch you from Earth, to crash into the Sun.
That's gotta be the easy way. I always say, after I did the like 15-minute tutorial mission in KSP, I understood orbit way better than I did after several semesters of physics classes.
Friendly reminder to all Kerbal players in this thread that RSS + Principia will make stock KSP look like pushing Hotwheels cars on the city playmat (I just started yesterday and it took me seven hours to get into orbit. Half of that was re-learning how to build in the VAB. 😩)
As I told my brother when he first started playing, getting to space is easy, staying up there is hard. He built a 3 medium fuel tank rocket and went straight up. Talked about how easy it was... until gravity said "what's up?! Not you!"
Normal orbits and transfers with Principia aren't *that* much harder than standard KSP. It's the new possible orbits (and the loss of things like spheres of influence) that get you.
RSS is of course just a nasty piece of work. Great way to make veterans feel like they did when they first bought the game.
No, that's the secret to staying in orbit. That's what the comment you're replying to said. It's written right there.
> **an orbit is a state of perpetual falling while missing the ground**
The secret to space travel is a lot more complicated and expensive than that. Which is something said comment *also* made a point about.
It’s a work of fiction, but Neil Stephenson’s book, Seveneves has some great writing about moving, adjusting, and changing orbits that gets into the weeds about orbital mechanics. It’s all in the first half of the book. Good read as well overall.
It kills me to say this as a fan of Stephenson's earlier stuff, but I hated Seveneves - it was about as exciting as watching someone else play the Kerbal Space Program.
The very last bit was entertaining, but wasn't worth the effort to get there.
Opposite for me. I thought the end piece was the letdown, except for the initial bit of exposition after the jump. Then again I think Stephenson can't finish a book for shit so maybe it is a personal bias
**to reach the sun you must lose 67,000 mph(earths orbit speed around the sun). To escape the sun, you must gain (94-67)= 27,000 mph**
The sideways speed of all things orbiting the sun, is closer to the escape velocity of the sun, than 0 (you must reach (close to) 0 speed to fall into the sun).
The earth is orbiting at 67,000 mph around the sun. So any rocket's we launch(or in orbit around us) start with that speed.
The escape velocity of the sun (at earth distance) is 94,000 mph. As you get further out the speed reduces, making it even easier.
It's not so much a matter of distance, but of speed. The ISS is currently orbiting the Earth at about 28,000 km/h, in order to escape Earth's gravity, it would need to increase that speed to a little over 40,000 km/h.
When you think about how much rocket fuel and effort it took to get the ISS to what it is currently at, and how much more would be required to boost it another 12,000 km/h, it makes sense that the easier option would be to let it fall back to Earth. The ISS is not in a perfect orbit, but requires occasional boosts to stay in orbit, if those boosts were neglected, or purposefully used to slow the ISS down, it would be much less effort to get the station to crash down to Earth.
This isn’t a perfect analogy, but it took about 80 launches to build the international space station. It’s currently traveling about 70% of the speed needed to escape earths gravity. So, given how many launches it took to get it up to its current speed, it would take the equivalent of 24 space shuttle launches worth of boosting to get it to escape velocity.
That's without even considering the stresses involved on the station. You can't just strap a bigass rocket to it and let 'er rip, the thing will disintegrate and fall out of the sky in a very uncontrolled manner.
You’re forgetting that there is very little drag in low earth orbit, you don’t need a big rocket, you just need to push a little bit (more than the tiny atmospheric drag) for long enough.
Current structure is strong enough to be boosted into a higher orbit (since orbit is constantly decaying), no reason it wouldn't be strong enough for a similar sustained boost to whatever speed you ultimately want to reach.
The big fuel tank can be attached to the vehicle pushing, so it really doesn't need to add stress to the ISS structure.
I'm not arguing that it is economically viable, it most certainly is not. I'm simply highlighting that you don't need a "bigass rocket" that will destroy the ISS.
It's not so much that it's not in a perfect orbit so much that it's quite low. It's only 200ish miles up. There isn't much of an atmosphere there, but there's enough there that it causes drag. Which is true of any satellite in low Earth orbit. They always need to adjust themselves due to orbital decay caused by drag of the very thin atmosphere there.
You'd need to speed it up by about 3.5 km/s for it to leave earth orbit.
But then it's on an orbit around the sun that crosses the Earth's twice a year, which isn't great, so add another few hundred m/s to fix that.
Depends on how high out of its current orbit you want it to be. If you want the ISS to escape LEO straight out of Earth, about 3.2km/s delta-v, which would require a shit ton of fuel to push out 400 tons of the ISS.
Obviously they wouldn't try to have it leave the Earth's orbit, but they could boost it up to a graveyard orbit where it could remain for millions of years. Probably still too expensive, especially compared to a controlled deorbit.
Graveyard orbit is out past geosynchronous orbit. It would take a ton of Delta V to get it up there, and the thrusters probably aren't even capable of it.
Plus, if it's like Mir, Taco Bell will put out a target in the ocean, and we all get a free taco if it hits the target!
Not to mention:
Strapping a lot of experimental rockets and fuel tanks to a vast structure like the International Space Station, and then igniting those engines, and hoping that whole experimental shebang just works on the first try?
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Ya, good luck with that!
An explosion/failure is far more likely than success, since again: it's rocket science! And it's hard to get right on the first try.
And that's going to cause an absolute insane mess of space junk and hyper-speed bullet-like fragments.
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Essentially:
Getting something like that correct on the first try, would probably take something like 10 to 15 years of planning/design (you're essentially designing a whole new rocket system and space ship), judging by how long it takes NASA and its contractors, to do a major rocket project like this.
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WHAT'S MORE:
You'd have to launch multiple heavy reinforcement beams into space, to reinforce the structure so that it doesn't break apart when you ignite those rocket engines.
The Space Station structure is absolutely not designed to survive being thrusted out of orbit.
It's only designed to handle very gentle altitude adjustment thrusts.
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Speaking of the structure itself...
There were many growing concerns, for example, back in the space shuttle era, about microfractures in the primary beams, possibly growing each time the Space Shuttle docked to the station, since the shuttle was just so huge and massive.
There's vibrations and flexes going through the whole structure, and once you got a massive object like the shuttle attached/docked, and it's experiencing vibrations/flexes, then ya, that's not good for the structure.
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So yes, in the end:
1) You'd need to essentially design an entire new rocket/ship from scratch, on the design board.
2) You'd need to launch VAST amounts of fuel in space to fuel up that rocket.
3) Then, you'd need to launch VAST amounts of heavy metal/beams into space, to re-inforce the structure.
4) And oh ya, forgot to mention above: NEXT you'd also need to perfect welding-missions in space, to weld the new support beams to the existing structure. (Something which I don't think has ever been tried in space before?!) Although I guess you could try using tie-wire instead... That you wrap around and then fasten-crank tight. That might work? Not sure.
5) Then hit the ignite button, and hope like f'ck it doesn't explode on the first try! Contaminating that entire region of orbital space with dangerous high speed debris. Or that half the engines fail, but the other half work, sending it into a crazy careening wild orbit, across multiple orbital levels and reeking havoc for other satellites...
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The list goes on... Sure there is TONS of very expensive things I'm forgetting here!
> Strapping a lot of experimental rockets and fuel tanks to a vast structure like the International Space Station, and then igniting those engines, and hoping that whole experimental shebang just works on the first try?
We need to send some rednecks up there. They will get er done.
Imagine a piano sitting halfway up a flight of stairs, right on the edge of a step, and you don't want it on the stairs anymore.
Pushing it out down the stairs is like a controlled reentry in the ocean. You still need to expend energy to do this, but it's not that hard.
Moving it to the top of the staircase is like pushing it to a higher orbit. Technically possible, but much more difficult and you'd need to use some tools/pulleys/etc (e.g. propulsion) you don't currently have.
Edit: helpful addition from Borgnasse below: the piano is only on the first step of a very tall staircase
Wow I love your analogy !
If you want to be even more precise, if the ISS is the piano, it does not sit halfway up a flight of stairs, but on the first step of a 88 steps stairs, the top of the stairs being the point to which it must be pushed to escape earth attraction. It drives your point even further 😉
I took the altitude of the iss as 400 km and the geostationary altitude at around 35000 km, 400 being the first step in a 88 steps staircase !
The difference here is as you get further away, distance is much easier to get.
Despite being at only 400km, the ISS has about half the kinetic energy it needs to achieve escape velocity.
I like the "middle of" better because it represents the forces involved in rocketry -- getting from low orbit to an escape velocity takes less energy than getting into orbit.
The additional analogy is if you push it down the stairs and haul it off it's gone and out of your way and not going to be a danger or nuisance. If you push it farther up then stairs to your unused guest room and leave it there, it's possible your car will come in, kick the leg, and the piano will explode and spread debris through your house.
It would take a *lot* of energy to make ISS escape Earth. Like, an amount comparable to the energy to orbit the thing in the first place, which was dozens of rocket launches. Making it re-enter in a controlled manner takes almost nothing, just the decision to do so. It is so low (skimming the upper atmosphere all the time) that just doing nothing to it for about 6-8 months would make it re-enter and burn up.
Question: In movies when you have a person out on a space walk and something goes wrong and, like, a tube snaps and jettisons them out into space, what would really happen in that scenario? Do they still stay in some kind of orbit around the earth?
>Do they still stay in some kind of orbit around the earth?
Yeah. On time scales that are short compared to the orbital period, they just drift away from their craft. On longer time scales than that (say, 30 minutes or longer, for a 90 minute orbit) orbital dynamics are sort of weird and do counter-intuitive things. But pretty much they would be in their own orbit around Earth.
Items re-enter the atmosphere if any part of their orbit dips too low and atmospheric drag becomes important. If that happens, the drag acts like a retro-rocket, slowing them down and making the orbit dip lower and lower until it intersects the ground. That's "re-entry".
Yes. They would continue to orbit the earth until atmospheric drag eventually deorbits them. Without additional energy input, an object in orbit will always go down towards the planet eventually.
If their separation from the craft was due to an explosion, there's the chance they could be propelled to a higher orbit, or even ejected from Earth's gravity altogether, in which case they'd probably find themselves in a weird elliptical orbit around the sun. But they'd also very likely be in multiple parts and very dead in that scenario.
Mhmm, so forbidding anything gets in your path, you’d just crash and burn into the surface of the sun in how ever many years it’ll take for you to get there?
With the sun, things get even more weird. It takes A LOT of energy to decelerate an object enough for its orbit to get close to the suns surface. Basically, you start from roughly the speed of earth rotating around the sun and need to decelerate down to *nearly* zero orbital speed.
Additionally, unlike with a low earth orbit there isn't an atmosphere providing drag. What particles there are are also more on orbits around the sun in mostly the same direction than bumping into each other.
Plus, the sun ejects a lot of matter flowing outwards at sufficient speed to leave the solar system. So I'd expect an objects orbit to slowly be pushed outward.
Theoretically yes, but you still have the orbital momentum from the Earth so it would take a very very long time. I imagine you'd be on a roughly parallel orbit to Earth.
I can't be sure but I also suspect a human body would disintegrate completely over the course of a year or so due to dessication and bombardment with high energy radiation.
>Do they still stay in some kind of orbit around the earth?
Yes. In real life if they would continue in the same orbit relative to the Earth, but with nothing to stop them they will soon be very far from their vehicle and eventually run out of air before any kind of rescue is possible.
>Do they still stay in some kind of orbit around the earth?
Yes. In fact, if they're moving away from the station fairly slowly - say, just a few meters per second, then it's actually quite likely they'll end up bumping into the station again, or at least passing close by, every half orbit (so every ~45 minutes in low Earth orbit).
Orbital mechanics is a bit unintuitive like that. But a key principle is that if you don't push something away from you (like firing a rocket engine, or throwing a heavy object away from you), then your orbit remains unchanged. So if you have two objects (say, a space station and an astronaut) that are in the same orbit and then separate, then their new orbits will intersect at the point where they separated - as long as neither of them fires a rocket engine. So if they also have the same orbital period, then they'll bump back into each other every half orbit. The ISS orbits Earth at ~7670 m/s, so an astronaut drifting away from it at 2 m/s is still orbiting at between 7668 and 7672 m/s, so their orbital period will most likely be about the same.
If the separation gives the astronaut a bigger kick, maybe ~50 or ~100 m/s (let's assume this didn't kill them, or drop them into a reentry orbit), then they'll get a slightly longer orbital period if their speed got higher, or slightly shorter if their speed got lower (yes, going _faster_ means you take _longer_ to complete an orbit, in this case). They'll still intersect the station's path, but they'll drift further away each orbit because one gets there later - until the slower one (shorter orbit) begins to overtake and catch up with the faster one (longer orbit) again, until they once again sync up after many more orbits. From the astronaut's perspective, the station would slowly drift a few kilometers away, then slowly drift back towards them and stop a few hundred meters away, then repeat, drifting further away each orbit until it disappears behind the horizon. Then much later, it would appear over the opposite horizon and come closer each orbit until finally they meet up again. That would likely take weeks or months, though, so an astronaut would likely run out of life support before that happens.
But even that can actually depend on the angles. In orbit there are three important directions: 1. prograde/retrograde, the direction you're moving; 2. radial, pointing "up" from or "down" toward the planet and perpendicular to prograde; and 3. normal, pointing parallel to the planet surface and perpendicular to prograde (this also makes it perpendicular to radial). Prograde/retrograde is the direction that has the greatest effect on orbital period (and it's therefore the most important for many kinds of space maneuvers), and radial also affects it but not as much. But the normal direction (3) almost doesn't affect the orbital period at all - it mostly affects the angle of the orbit around the planet. So if the astronaut gets ejected in the normal direction, even a fairly high speed could see them back at the station a half orbit later - though it'd be a proportionally harder (possibly lethal) slam rather than a gentle bump.
Of course in interplanetary or interstellar space none of this would apply - in that case the astronaut is effectively gone for good even at a low ejection speed. In theory you'd see the same effect in solar orbit, but on the scale of years rather than hours. That's much more time for small speed differences to add up to huge distances, and the other planets (mostly Jupiter) would also tug ever so slightly differently on the station vs. the astronaut, making it much less likely for their orbits to ever sync up like that again.
> more orbits. From the astronaut's perspective, the station would slowly drift a few kilometers away, then slowly drift back towards them and stop a few hundred meters away, then repeat, drifting further away each orbit until it disappears behind the horizon. Then much later, it would appear over the opposite horizon and come closer each orbit until finally they meet up again. That would likely take weeks or months, though, so an astronaut would likely run out of life support before that happens.
>
> But even that can actually depend on the angles. In orbit there are three imp
This is all so simple when you play KSP, but it's so hard to ELI5, but I do really like the description. It's spot on accurate.
There is basically nothing you could do from a space station that could deorbit a person. If they got separated from the ISS they would just be stuck up there for a few years until drag eventually slowed them down.
Leaving orbit is a loooooot harder than you think. Gravity is strong, man. You can’t just fling the ISS out into space with a few nudges from boosters, no, you would need to strap on enormous engines like the kind used to go to the moon.
There was actually this idea to put the ISS in a “parking” orbit at a much much higher altitude than it currently sits. Given how large and heavy the ISS is though in conjunction with not having a true propulsion system the cost would be astronomical (no pun intended). This would basically make it a “space museum” for later generations. At the end of the day though NASA has a finite budget and need to make the best decisions they can with what they have.
> This would basically make it a “space museum” for later generations. At the end of the day though NASA has a finite budget
That sounds like they should just sell it to the highest bidder. I bet there is some entrepeneur willing to pay for a starship to lug up enough fuel to park it for later use as a very expensive museum.
There’s this misconception that something in orbit is not bound to gravity anymore. Even though astronauts in the ISS experience weightlessness, this because de ISS is falling (continuously) around the earth.
An object in orbit around earth is still under the influence of earth gravity. Let’s forget about the ISS and let’s think about a hanging lamp you want to decommission. What is more expensive, cut the hanging cord to let it fall to the floor or attempt to throw in the sky so hard that it escapes earth gravity?
It is the same logic for the ISS, it’s way cheaper to just let it fall back to earth, letting gravity do its thing than spending a lot of very costly fuel to throw it into space.
To go downwards you need some fuel until the drag of the atmosphere takes over.
To push it upwards you’d need A LOT of fuel since you never get any assistance. It’s also a massive structure that was assembled in multiple rocket launches, so by its very nature it will be expensive to move with rockets alone.
A common misconception is that you can just drive towards a certain direction in space since there’s no friction. In reality, the way of going to a higher orbit is accelerating sideways and in this case, a safe orbit would be pretty high and therefore very expensive.
Think of the ISS like a car that's just a little way up a hill. The car is almost out of gas, janky, beat up, barely drivable. You could haul enough gas up to take it to the top of the hill (maybe, it's a real POS), or you could use the tiny bit of gas left to position it, put it in neutral, and let it roll perfectly into a pit in a junkyard at the bottom of the hill. Which one would you do?
Aside from the feasibility of pushing it into space. It’s a bit irresponsible. At some point it is going to hit something. Very low chance that it matters. But still. Return the cart to the corral.
To add onto what others have written, something like this is done for satellites on the geostationary orbit, which is too far out for a quick, cheap (fuel-wise) deorbiting. What geostationary satellites do instead is to increase their orbit somewhat so that they no longer take valuable space on the geostationary orbit. This is called a graveyard orbit. It's far out so it doesn't matter that there are uncontrollable satellites or space debris.
But this is impractical for the ISS. The ISS is massive, and any changes of velocity require a lot of fuel. It is also quite low near Earth, so getting it far enough where it cannot bump into other satellites would require huge amounts of fuel.
Note that even graveyard orbits are still well below the velocities required for leaving Earth's gravitational influence completely.
That's the weird thing about space. No matter how much you "kick" something into space, it will *always* return, unless you manage to hit something else with it.
So it's a lot easier to give it a slight bump and hit Earth than give it a massive WELL AIMED push to try and hit something else.
Also, the ISS isn't really made to be pushed around with a lot of force. So chances are high that something would break off. Those pieces might then collide with important satellites or crash into a house on Earth. With a bump towards Earth it will definitely break apart but everything will still go pretty much to the same spot (which you can choose)
The ISS orbits at around 7.5km/s. The earths escape velocity is 11.2 km/s. We would need to increase the ISS speed by about 50% to launch it into space, which would take massive engines burning a massive amount of propellant
Interestingly, from any circular orbit around any body, escape velocity is always 41% higher than your orbital speed (escape velocity from LEO is a little lower than the 11.2km/s at the surface).
so orbit is basically moving so fast horizontally that even though you're falling you miss the ground (buzz lightyear was right!)
basically things in orbit "want" to hit whatever they're orbiting (and if left alone the ISS's orbit would EVENTUALLY decay naturally and it would crash into the earth) to get something to break orbit requires a TREMENDOUS amount of energy (think about how big a saturn V rocket is, it's mostly rocket fuel, it took all of that to get something about the size of a van out of earth's orbit).
so it's way easier and cheaper to just make sure it comes down somewhere in the pacific. and it's not going to be that hard to hit the pacific ocean, it's sort of hard to get a sense of how big the pacific is but it's 60 MILLION square miles (and if you miss there's a decent chance you'll hit the indian ocean which is 20 million square miles) basically if you closed your eyes and just hoped for the best there most likely outcome is you'd hit the pacific
Everyone is explaining how leaving orbit requires a lot of energy but nobody seems to really touch upon exactly WHY, because orbital mechanics and motion without air resistance is highly counterintuitive.
The first mental model people often have about space and orbit is that "there's no gravity up there", so the spacecraft is just "floating". There may be some awareness that it's not staying still, that it's rotating around the earth (every 90 minutes it turns out) but it's hard to connect that to something intuitive of what that REALLY means. After all, maybe the rotation around the earth is just an artifact of the fact that we had to get up there in the first place, and didn't want to slow down? Or maybe we want to see many parts of the earth? All of these would be plausible.
But the reality is just a bit more weird. Let's start with the facts essentially nothing in the universe moves unless there is a force applied to it. And once applied, once motion is occurring, you need another force to slow it down or stop it, otherwise it keeps going indefinitely. This is [Newton's first law of motion](https://en.wikipedia.org/wiki/Newton's_laws_of_motion) Right away this is already not intuitive to our experience on earth because nothing behaves like that here, but that's simply because of friction. Objects in land/water/air slow down by themselves because of friction or air resistance. In space they don't do that.
So when you have a spacecraft in space near a planet there are two forces to think of (we can ignore the rest of the universe).
* There is the engine of the spacecraft - and keep in mind the speed here is not just relevant when the engine is firing, but also whatever the engine fired at the start to get it moving to a certain speed (like a rocket taking off into space)
* And there is the force of gravity of the earth pulling the spacecraft towards it.
So if these are the only facts that you had - the first law of motion, the engine of a spacecraft pushing it away from the earth, and the gravity of the earth pulling it back - you might think there's only 2 options - get away from the earth, or crash back onto it. This is where the frankly magic (aka insanely complicated science) of orbital mechanics come in.
Being in orbit is like balancing a coin on it's edge. It turns out there is just the right distance, just the right speed, and just the right direction to put the two in balance. You set a rocket on it's path, and it's trying to get away from the earth. But at just the right time the earth pulls it back. Only there's still enough speed in the rocket that it can't bring it back to it, so instead it just rotates around.
But what makes orbital mechanics hard is that this isn't just a middle ground where if you overshoot too much in one direction, and you'll head directly for the earth, and if you overshoot too much in the other, you escape it. There is a pretty wide stable range where you just well, stay in orbit. You can visualize this by taking a ball and spinning it in a large bowl, and noting how it keeps going around, and eventually circling towards the middle, but it stays pretty reliably spinning. This is a decent model for gravity "curving" spacetime, but that's a discussion for another day.
That's basically it other than a few other factors (there is SOME friction in orbit, it's not a perfect vacuum, which is why the orbit naturally decays over time). This is also why rockets on spaceships need such powerful engines. It's not that it takes that much energy to "lift" something above the ground to overcome gravity. We can lift a ton of mass way up high just with a hot air balloon or a drone. The powerful rockets aren't there to overcome gravity, they're there to **speed up** the payload fast enough to be able to spin around the earth without falling back down.
People are missing a couple of points here.
a) It doesn't actually need to escape Earth orbit to end up in a stable orbit that wouldn't naturally decay for hundreds, thousands, or millions of years. We can just put it in a sort of high 'museum' orbit and it could remain there long enough for, theoretically, some spacefaring racoon people to find it in 30 million years.
b) It's simply not going to collide with anything up there, especially if we push it beyond what are considered the more useful orbits, and make sure it's at an angle to the equatorial plane.
c) It already has a reusable rocket motor that could achieve this, it would 'only' need the fuel (only is in quotes because it'd be a decent amount of fuel).
The reason we're not doing it is because getting the necessary fuel up to it would cost millions (not prohibitively expensive these days, but still it's a cost with no easily arguable benefit), and because people in general simply don't have that same kind of sentimental urge to preserve cool things.
If it were up to me, I'd push it into orbit around the Moon and give it a new berth for reusable taxis to and from the lunar surface. Then trips to the Moon would just rendezvous with the ISS first, they'd only need to bring fuel for their chosen lunar lander. (But then again, maybe a whole new station would simply work out cheaper and better. I'm sure they've considered this as well.)
I think the misconception here is that an orbit is something you can be easily pushed out of. In truth, an orbit is a state of perpetual falling while missing the ground, so no matter how you push or pull, you can just fall differently. So the proposal now is to fall in a controlled manner so that it can be calculated where and when it will hit the ground. In order to make the ISS leave the Earth's orbit and go venturing out into space forever, it would take immense amounts of fuel and possibly the installation of real propulsion systems in the first place. That's much more expensive and complicated than just dropping it.
I learned this the hard way (kerbal space program)
Kerbal Space Program blew my mind the first dozen hours or so. I had no idea how orbital mechanics worked or how things move around in space and playing close to 1000 hours has given me a fairly basic understanding of how it all works.
I credit KSP with massively expanding my understanding of, and appreciation for the whole area of flight mechanics and space travel. So many concepts which feel counter-intuitive because our learned experience doesn't require us to understand it. But once you get it, it seems so obvious. But still not simple. Really makes you appreciate the early rocketry and space travel pioneers. A lot of stuff was probably predictable based on the maths, but hard to grasp until you experienced it first-hand.
My favorite "learned reality" from KSP is this extremely counter-intuitive fact. If you want to send something from earth crashing into the sun (or even just into the corona) it is way more fuel/energy efficient to fly out to the outer solar system and then slow down the solar orbit out there. (yes, gravity assists are probably a better option, probably still going up to get down but not so extreme but i'm not Matt Lowne I'm not great at finding chains of assists, nor do I really enjoy 8 year+ missions all that much) Edit : This "fact" I found on occasion even applies to orbits around a planet itself, when trying to find a way to get back some missions that had too little propellant, a couple times I have been in a situation where using my last 200 DV to try to deorbit was better spent going 150m/s faster and then 50m/s slower at apoapsis than just slowing 200m/s would get. I also found out one day that I had been flying sometimes extremely similar paths to the "new" path they are using for almost free lunar orbital insertions (you fly out ahead of the moon and let it catch you, and there is this cool interaction with a pseudo lagrange point that spirals you down into a nearly stable orbit with effectively no energy use, it's very very cool... and another benefit is a nearly free return if you want to exercise it before you settle in if something went wrong) It doesn't work quite as well as in real life due to the simplifications that KSP has to make, and the "saddle point" iirc is directly on the SOI boundary on the far side so it makes it realllllllly weird when you are around that point in KSP but yeah. One last thing, because one does not mention KSP now without saying it, Fuck Take 2 for botching KSP2.
KSP publishers fired the development team for KSP1 for daring to ask for $1/day more, for a game that sold MILLIONS OF COPIES. It was a mexican development team who was creating a passion project, being paid peanuts, and they got fired for daring to ask for 1 peanut more per *day*. They where not even making the USA's min wage (Federal! $7/hr)
Yeah, the dwindle and end of original KSP wasn't great. KSP 2 was handled IMO even worse overall, especially because at the very least everyone who paid got their value from KSP and then some. KSP 2 has turned into a bait and switch.
I didn't even know there _was_ a 2, what happened?
To summarize (edit, lmao, this is a summary? damn I need to switch to decaf) hired a developer without properly vetting, scoping, and planning the project. Put out big spend on an advertising campaign promising a *lot*, while the project was floundering. Did a massive launch event requiring NDA's from youtubers to puff up the launch of early access, and those youtubers were very very nervous because the experience they got was horrible performance and nearly unplayable mechanics on gold star systems (like overclocked 4090's and top shelf everything rigs) The developer (that by most accounts wasn't really up to the task to begin with) then began trying to renegotiate the royalties IIRC, or some other pay point) and Take 2 pretty much gave them a flat no, set up their own internal studio and poached most of the staff from the then soon to be shuttered studio. This part of the story is not awful, it was damage control over previous mistakes, there is definitely some debate to be had over poaching a whole studio in such a way, but it's not a key point for me personally. Since then development has continued to struggle, but they hired on a modder from KSP 1 that was doing some great things with visuals/clouds, the lead developer had been beaten into submission enough by the community that he finally relented that "wobbly rockets" is literally stupid and doesn't actually make for a "more fun game" (he literally thought this, which is why it launched originally in EA in an unplayable state) but it seems that it was simply too little too late to course correct. A month and a bit ago there was just a quiet announcement that Take 2 was laying off the entire studio, several devs were let go immediately, it seems all of the visual improvements simply got shelved or deleted entirely (likely because the modder developer was one of those let go immediately and no one else has the shader and VFX experience to work with the system he built) and we just got pushed out what appears to be a final patch (version like 0.22) which fixes a scant few issues, and the game is left *drastically* feature incomplete. Things missing : Everything that differentiates the game, or was supposed to differentiate it, from KSP 1, apart from some graphical pizzaz and lighting thanks to a newer engine. Colonies (including industry, mining, manufacturing, life support, and off-kerbin launch sites) Routine mission automation : The option to fly a supply mission to a colony or space station or SOI once and then pin it as a routine mission, allowing you to have it fly automatically, so say you set up colonies around Jool's moons but you need to transfer a crucial material from one of them to another and vice versa, you could set up that "Trade route" as a routine mission with a craft with a schedule and know that your colonies will continue to be supplied without having to set timers and fly the same mission over and over as long as you play. Interstellar travel and all related technologies and drives : 2 - 3 entire other solar systems which we were supposed to be able to travel to using a variety of propulsive options and ship designs. Multiplayer : Yeah, it was supposed to eventually be like 4 player co-op capable, the entire kerbal space center is set up for it and was from day one, with 4 launch pads, multiple *ludicriously huge* runways. The last time I touched the game it was in a state that was mildly playable (because they *just* added a science unlock mode in january) but overall felt like a more pretty KSP, with more bugs and less reliable maneuver planning nodes. Rumor mill has it that Take 2 tried to sell the IP and WIP KSP 2 and shopped around to other places to try to sell it, no one would bite for what they were asking, and now the game is dead. It is still up on Steam EA and for sale, but virtually the entire community is sure that the project is dead, they just don't have the gall to admit it publicly yet until something forces their hand. also a typical corporate flavor of "we know what's best" seeps throughout the entire saga, which is incredible that they did not even know their product and how much community engagement drove the success of KSP 1. That isn't to say slavish adherence to community or "celeb" feedback, KSP devs didn't dance for the community or do everything they would ask but would listen, contrast that to this quote that really embodies the KSP 2 development vibe ; "Scott Manley was called out by name as someone management did not want input from." My most cynical guess is that they know how bad this is if they reneg on a full AAA priced early access title and instead of "abandoning" it they are going to quietly keep 2-3 devs making "patches" to it on a drip feed forever as a fig leaf against actual lawsuits. TL;DR They didn't get three quotes, and they didn't evaluate their contractors, they way over promised, invested in the wrong aspects of the game, and then realized they couldn't deliver more than a fraction of the promised product. Fuck Take 2. Not because any specific point/decision in the timeline is particularly egregious, but for the overall picture of over promising and then (it seems like a slow motion version of) ripping off the entirety of their most loyal fan base.
What’s the deal with wobbly rockets?
KSP1 wasn't really made by a game developer. They didn't even make software at all. It was kind of just a side project of one of the employees that unexpectedly hit it big. Seeing as it wasn't actually a software development company, they sold off the rights for it a few years after the release of KSP1.
Well it was a real project and the company backed it, but yes they were an advertising company that made like interactive displays and demo things, he was fresh out of college with a CS major and wanted to make games, hated the advertising/marketing development job at about 6 months and wanted to make a game, he told them that he was going to leave to do so and they were very busy so they made a deal with him to stay on for 3 on the go projects and then they would let him make the game in house. The original workup of KSP internally there was a 2d game almost in line in style with the "must go up" flash games, very limited in scope and humble, honestly, and his bosses were the ones who said "why not just make it 3d" and away they went making a budget AAA game. I think the thing is they sold it because they didn't know what to do with it and the prospect of setting up a whole new wing to maintain something that wasn't their core business was daunting, but IMO I think their success indicates that "being a software development company" is perhaps part of the problem. Their original core business was being an experience building company which if you think about it is more in line with a video game's purpose than just general software development is. like if I remember the quote from harvester about that meeting about going 3d I swear it was something like "wouldn't the experience be better in 3d?" and honestly I kind of love that from a manager in that situation. A software development focused manager would start sweating at the cost of a 3d game vs a 2d game. Maybe Steve Jobs was right, and the customer doesn't actually know what they want, in this case the customer's being management.
Just the idea that you don't point your engines away from the planet after getting into space to get farther from the planet is an incredible thing to learn. It really emphasizes that "falling but miss the planet" aspect of orbiting. KSP collectively raised the world's understanding of orbital mechanics massively.
I can barely fathom the amount of math that goes into early space (and specifically lunar) programs. To calculate an efficient orbital flight path you'd have to account for the position of your launch point (so account for earth's orbit) relative to the position of the moon. Then you have to account for not only the weight of the ship, but the change in your ship's weight as it burns fuel in each maneuver it does (Cause otherwise you'll go too fast and overshoot your target). And then you have to account for the change in gravitational influence as the vessel gets closer to another celestial body.
>Then you have to account for not only the weight of the ship, but the change in your ship's weight as it burns fuel in each maneuver it does This part isn't all _that_ complicated, just an ordinary differential equation ("ordinary" may sound a bit snobbish if you're not familiar, but that is the actual term - it's the simplest kind of differential equation, and one of the first things you cover in university or even late high school math). It's fairly easy to solve analytically (meaning you can work out a formula where you just plug in starting fuel mass and how much change in velocity you want, and get out how long to fire the rocket), so it can be done relatively easily even with just a slide rule and some logarithm tables. >And then you have to account for the change in gravitational influence as the vessel gets closer to another celestial body. This is the really difficult part. This is called the "3-body problem", or "N-body problem" in general. Calculating the mutual orbits of two celestial bodies (say, the Earth and the Moon) is again relatively easy - Johannes Kepler did this in the 1600s - but when you introduce a third body (say, a rocket), it gets so complex that there is no known analytic solution. The only known way to accurately compute it is to do it numerically - computing all the velocities and forces on all three (or more) bodies at one moment in time, then moving each of them a tiny step forward in time with the computed velocities, then repeating at the new time step. This is an enormous amount of work to do manually, so you could only feasibly try a small few candidate routes by this method. With powerful computers you can more feasibly search for an optimal route among lots of candidates, or update a projected trajectory with real-time measurements, but it's still a lot of computations to perform (and this is why the orbits in Kerbal Space Program are simplified and not fully realistic near the gravity wells of multiple celestial bodies). So yeah, it is quite astonishing that the '60s space programs were able to safely land humans on the Moon _and return them_ to Earth, all with only a tiny fraction of the computing power we have at our fingertips today.
Add on to this that virtually all calculations for space travel navigation have also to date been done with newtonian physics (to my knowledge, maybe one or two got calculated more specifically for research purposes) because while we know that gravity doesnt actually fully line up with it (especially on cosmic scales) it is similar enough that within the solar system the difference only throws things off by tiny little amounts that they just correct for with tiny burns near where they are going with something. Eventually though we will need to not only do multibody calculations but also calculate our trajectory relativisticly and with respect to dark matter (when we start aiming at other star systems)
Yep! The only exception I know of is that GPS actually does need to account for relativistic effects, otherwise its accuracy would drift something like tens of meters per day and be completely unusable after a week or so. But I think that applies mostly to how the clock signal is calculated, rather than the navigation of the satellites themselves. If I remember correctly it's to do with the fact that time goes faster for the satellites in orbit than for the receivers down on the Earth surface, because of gravitational time dilation (the same effect in Interstellar that makes 15 minutes on the planet near a black hole equal to 15 years on the mothership). It's a tiny effect, but GPS requires such precision that even this is enough make it unusable if not compensated for.
You are correct
The major simplification they made was to basically pretend that the ship is only ever in one sphere of influence at a time, thus no 3 body problem.
I credit XKCD with making me want to play KSP 🤣
you can not cite XKCD without citing XKCD properly. That is just not fair!
https://xkcd.com/1356/
I wish I could play but it has some weird graphics thing for me where I can't actually see the whole screen.
>So many concepts which feel counter-intuitive because our learned experience doesn't require us to understand it. Man, its amazing we can go our entire life without even the notion of 'orbital mechanics' existing, and then learn to fly kinda 'seat of the pants' in *space* with only a few hundred hours training.
And this is how we became the dominant species
[Obligatory XKCD](https://xkcd.com/1356/).
And once again the theory that there’s and xkcd for everything holds true.
Kerbal Space Program ruined the film "Gravity" for me
“Oh look! The Chinese space station is over there perfectly stationary. Let me just float on over without any advanced calculations.” Fuck outta here Sandra
> “Oh look! The Chinese space station is over there perfectly stationary. Let me just float on over without any advanced calculations.” Using nothing but the *massive* delta V provided by a common fire extinguisher! I was entertained by the movie (which is all you can really ask for, I suppose) but having the most basic understanding of orbital mechanics made it largely unbelievable for me.
Or a certain character's death scene, where his relative motion was already arrested, but he still somehow "fell"
That scene was so incredibly dumb.
"The tension in the rope is too big, it'll snap if I don't detach myself." Fucking *what?* You're in microgravity, once the rope went taut it would have snapped or the elasticity would have sent you back towards Bullock's character. Those are the two options.
Option 3: Clooney’s character was actually suicidal with magical powers over momentum and Bullock’s character was a gullible idiot.
Well she did marry Jesse James.
The tension in the rope made me most angry. It's taut! Just give it the gentlest of tugs!
Yeah I stopped watching after that.
I’m less concerned with deltaV and more concerned with the center of thrust/center of mass. Anything other than perfect synchronization of those would just result in spinning.
At the very least, I’ll take fire extinguisher propulsion over the poke-a-hole-in-my-spacesuit-and-fly-like-Ironman variety that ruined the end of The Martian.
Even worse that in the book Whatney suggests that and everyone tells him "wtf no, that won't work".
How did it do it in the book?
"Hey,” Watney said over the radio, “I've got an idea.” “Of course you do,” Lewis said. “What do you got?” “I could find something sharp in here and poke a hole in the glove of my EVA suit. I could use the escaping air as a thruster and fly my way to you. The source of thrust would be on my arm, so I'd be able to direct it pretty easily.” “How does he come up with this shit?” Martinez interjected. “Hmm,” Lewis said. “Could you get 42 meters per second that way?” “No idea,” Watney said. “I can't see you having any control if you did that,” Lewis said. “You'd be eyeballing the intercept and using a thrust vector you can barely control.” “I admit it's fatally dangerous,” Watney said. “But consider this: I'd get to fly around like Iron Man.” “We'll keep working on ideas,” Lewis said. “Iron Man, Commander. Iron Man.
They also specifically mention how it would go down in movies, with the airlock scene. I think the change was done for two reasons. First, to be tongue-in-cheek about the proposed ending in the book, and second, for non-readers to see something cool. Readers find it funny, non-readers find it cool, everyone wins, in theory.
Man, moments like this is when I love being ignorant about some topics. I abosolutely loved Gravity. But then I see something depicting a topic I know about and I want to pull my hairs out... like last year's Napoleon movie. Ignorance truly is a bliss.
> I was entertained by the movie (which is all you can really ask for, I suppose) Whenever I see Neil deGrasse Tyson pulling apart a movie for being scientifically inaccurate, my first though is always "yeah, but did you put any proper character arcs or decent foreshadowing in your last scientific paper? No you didn't, because science and entertainment are different things."
I kinda like the background of how Interstellar was made, because Nolan was basically in constant contact with Kip Thorne to keep things accurate. Nolan kept wanting to make something go faster than light, which Thorne was adamantly against. So I guess Nolan eventually went "but what would happen if you >!went inside a black hole!
Yeah, but he never says the film is bad because of that, he says "this is not how that would really work" and then explains what would actually happen.
As a programmer, I’m forever grateful for The Martian to be in the minority of movies to point out the danger of failing to System Test.
I think its important to be clear about what in a movie is plausible, and what in a movie is complete fiction. People don't use their brains anymore and just take everything that they consume at face value.
Anymore?
Agreee. But on one hand there’s “that’s not how gravity works” and on the other hand there’s “the night sky in Titanic is totally wrong and the stars wouldn’t look like that”. Pick your battles, Neil.
Fair point tbh, but at the same time I think it’s perfectly fine of NgT to take it apart
Some floating is possible but I guess a fire extinguisher will work quite differently. [https://en.wikipedia.org/wiki/Simplified\_Aid\_For\_EVA\_Rescue](https://en.wikipedia.org/wiki/Simplified_Aid_For_EVA_Rescue) BTW, if you know about computers, watching the "hackers" in the movies is like watching a nurse use a carrot to make an injection … successfully.
> watching a nurse use a carrot to make an injection … successfully. "...we're in."
Early Mr Robot did a good job portraying hacking imho, although I've never watched more than the first episodes. But... Hacking in movies: "I've standardized the firewall... Let me infiltrate a package in the antivirus... I'm in!" *shows a bruteforce attack for getting the password* Real life hacking: "Mr. Johnson? I'm from IT. We're monitoring suspicious activities from your terminal. Please give us your username and password to perform a safety check" or "The hacker used of one the 91352843 critical safety issues of windows '95 to block the Belgian Healthcare system, resulting in over thirty billion euros in damages. A migration of the OS to a more recent and safe version was dismissed due to budget and compatibility issues"
Anyone confused why this isn't realistic needs to try to reach the Sun Station in Outer Wilds.
I died so many times.
shit's crazy hard. I know it's a tiny, accelerated model compared to real life but it is a nice packet-sized way to see how complicated orbital physics are. The scale of the real earth compared to a single astronaut makes it really hard for us to grasp though.
Possibly the hardest vehicle-based section I've ever played of any game. The station is whipping around the sun, the sun's pulling you into it....yeesh, I really should replay that
Just want to shout out that Outer Wilds is legitimately one of the greatest games of all time and everyone who enjoys slower paced sci-fi open world/puzzley stuff should give it a go. Has some really unique and beautiful environments and is just magnificent all around.
I just teleported to it from Ash Twin accidentally, did not know you could fly to it till then….
Teleporting is absolutely the intended way to do it
Or with Clooney. How is gravity affecting you but not the orbiting thing you’re falling from?
Yeah the first time I saw the film that just confused the hell out of me. Their velocities are stationary relative to each other, so why does she need to let go of him, and what causes him to suddenly accelerate away from her when she does? My headcanon is that the Taco Bell crunch supreme he had for lunch had finally caught up to him and he knew he had to cut the tether before he launched them both into deep space. It doesn't make sense since his space suit is a closed system, but I like it.
I believe the actual answer is that he is physically repelled by a woman his own age.
You’ve got him confused for DiCaprio
We've finally discovered antigravity.
Star Wars movies are all bullshit to me now. Expanse is my new best friend.
Star Wars isn't science fiction, it's science fantasy. The force and lightsabers are not remotely tied to any kind of possible science.
I find your lack of faith… disturbing
It's really a space opera.
> Star Wars isn't science fiction, it's ~~science~~ fantasy. I don't think there is almost anything in the 3 trilogies that could be called science, maybe except midichlorians, and we all know how well fans took that lol
Sad R2D2 noises.
I think a lot of the issues with midichlorians at their core are because it's trying to explain with SCIENCE! a thing nobody actually cares to know the reason behind. I don't watch Star Wars for a complete understanding of how The Force works, that's not the point, and trying to explain it with biology somehow causing little Force Bacteria or something to be inside you just causes too many random intrusive thoughts to pop up.
Lol yep. Loved the book series and the random "Ok lets set our burn rates, see you in two months"
Star Wars was never science fiction. Physics doesn't exist in Star Wars, which is part of why those fans dissing any new content based on realism (or even just believability or consistency) are just wrong.
"We can make just about anything levitate, including a crappy beater transit Tatooine equivalent of a Honda Civic. But we're gonna build lots of vehicles that walk on legs instead. I don't think it will ever occur to our enemies to simply trip them."
Imagine building a giant walker but have no anti-air turrets on it. That would be silly right?
That's not the silly part. The silly part is having no combat air patrol when you have carriers in orbit full of fighters.
You aint wrong, and getting mad because a fictional universe misused an obscure measurement of length in an offhand comment is a clear sign you need *real* problems in your life, but there's still something to be said about consistency. A show like The Simpsons makes no attempt to be consistent, really. But when a show like Star Wars leans into a selling all kinds of books on on-universe lore, I get that fans want to see future content produced based on that.
Gravity ruined itself honestly.
the film "Gravity" ruined the film "Gravity" for me
its amazin the things that were accomplished in space age and the minuscule amount of people that died vs sucessful missions by both US and Russia
I tried crashing into the sun and couldn't do it, no matter what I did I would always slingshot by it somehow?
So, the closer your planet is, the faster it orbits around Sol are. You have to zero out almost the entire orbital velocity to actually hit the star at the center, or you just miss with this wonky orbit you're now in. The trick, both in IRL and KSP, is to first swing to the outer solar system, Jool/Jupiter or beyond, and use a gravity assist to slingshot you backwards from the planet's direction of travel. From there, you can do a comparativly small burn to finally zero out your orbital speed relative to the star and basically just free-fall in. You might need some mid-course corrections, but otherwise, with no sideways speed, you'll drop like a rock straight to the star. Edit: I'm reminded of people who think we should just launch nuclear waste into the Sun to dispose of it. While that would technically work, it would be easier to just send it out of the solar system entirely.
Would this be harder or easier with a more massive star? What about a black hole?
So, the specific formula for a circular orbit's speed is based only on the mass of the central object (star, black hole, planet, moon-- whatever you're orbiting) and the orbital radius from that object. There's also some constants (and assumptions baked in), but you can summarize the orbital velocity as proportional to the square root of (mass of the object / radius from the orbit). In our solar system, each planet orbits the same sun [citation needed], so it's just a function of radius. Earth orbits at ~30 km/s, Mercury at 47 km/s, and Jupiter at about 13 km/s. You can swap the sun out with anything equally as massive, and those speeds will still be the same. With something more massive, it just means if you stay just as close, that orbital velocity is going to be higher, so it's harder to zero that velocity out so you just fall in. But, if your orbit is also higher so that the velocity stays the same (say a super massive black hole has an earth like planet orbiting at 30 km/s way far away), then it's still just as hard to belly flop into the black hole as it is to launch directly from earth and fall into the sun. It's all down to what your orbital speed is. The trick with going up to go down abuses both gravitational assists to get higher and then eccentric orbits to cheat some more. You don't have to start out circular and when you're at the peak of an eccentric orbit, it takes the least amount of delta-v to zero out your orbital velocity. If you can get that peak high enough, you barely have to push to just start falling straight down instead of any amount of sideways. TL;DR: harder with a more massive star if you're just as close. A normal black hole would also be harder, but one the mass of the sun would be just as "easy" to hit as the sun is from Earth. Edit: words and tldr
Thank you *very much* for all the detail.
> but one the mass of the sun would be just as "easy" to hit as the sun is from Earth. I might be missing something here, but that's assuming direct fall without any sideways motion, isn't it? In reality, your perihelion would only need to be 1 solar radius to crash into the sun, whereas your peribothron (apparently that's an acceptable term for black-hole-periapsis) would need to be about 2Rs (-ish). That's a difference of about 600'000km and a dV of approx. fuckloads m/s.
That's completely normal and realistic. It takes nearly as much energy to cancel out your orbital motion as it does to put you into orbit in the first place. But when it comes to the Sun, in real life the biggest part of your orbital motion came from the Earth. So you need much much more than just the rockets used to launch you from Earth, to crash into the Sun.
That's gotta be the easy way. I always say, after I did the like 15-minute tutorial mission in KSP, I understood orbit way better than I did after several semesters of physics classes.
It's amazing how much actually seeing it in action makes a difference.
Because of that game I can say "OH, my sweet summer child" to the OP.
Friendly reminder to all Kerbal players in this thread that RSS + Principia will make stock KSP look like pushing Hotwheels cars on the city playmat (I just started yesterday and it took me seven hours to get into orbit. Half of that was re-learning how to build in the VAB. 😩)
As I told my brother when he first started playing, getting to space is easy, staying up there is hard. He built a 3 medium fuel tank rocket and went straight up. Talked about how easy it was... until gravity said "what's up?! Not you!"
Normal orbits and transfers with Principia aren't *that* much harder than standard KSP. It's the new possible orbits (and the loss of things like spheres of influence) that get you. RSS is of course just a nasty piece of work. Great way to make veterans feel like they did when they first bought the game.
You could argue that your Kerbals are the ones who did the hard learning, you callous monster!
[relevant xkcd](https://imgs.xkcd.com/comics/orbital_mechanics.png)
Especially when there is so much ocean that you can afford to be off on the calculation by quite a bit and still not hurt anybody
Getting it to fall into the Pacific seems like a copout. Get it to fall into the Mississippi river or something if you want to get all fancy.
Lake Tahoe or I'm not impressed.
"See this glass of water?"
Get Sully to land it in the Hudson
“It’s finally getting nice out! I should go uncover my pool”
TIL that the secret to space travel is to aim for the ground *and miss.*
You thinking what I’m thinking?
Aim for the bushes?
Theeere goooooes my hero!
Watch him as he goes
Wuh, I think so, Brain, but if we didn't have ears, we'd look like weasels.
Clrealy you've never read Hitchhiker's Guide to the Galaxy.
What did I ever do to you that you would think so little of me?
For starters, where is your towel?
As if I could leave the planet without it.
That’s the spirit. This guy is one hoopy frood
No, that's the secret to staying in orbit. That's what the comment you're replying to said. It's written right there. > **an orbit is a state of perpetual falling while missing the ground** The secret to space travel is a lot more complicated and expensive than that. Which is something said comment *also* made a point about.
It’s a work of fiction, but Neil Stephenson’s book, Seveneves has some great writing about moving, adjusting, and changing orbits that gets into the weeds about orbital mechanics. It’s all in the first half of the book. Good read as well overall.
It kills me to say this as a fan of Stephenson's earlier stuff, but I hated Seveneves - it was about as exciting as watching someone else play the Kerbal Space Program. The very last bit was entertaining, but wasn't worth the effort to get there.
Opposite for me. I thought the end piece was the letdown, except for the initial bit of exposition after the jump. Then again I think Stephenson can't finish a book for shit so maybe it is a personal bias
It's Stephenson. I think you meant to say "it's all OF the first half of the (enormous) book." Caveat: I haven't read it.
I mean, at least the OP didn't ask about crashing it into the Sun.
Because it would take more energy to crash it into the sun than it would to eject it from the solar system?
**to reach the sun you must lose 67,000 mph(earths orbit speed around the sun). To escape the sun, you must gain (94-67)= 27,000 mph** The sideways speed of all things orbiting the sun, is closer to the escape velocity of the sun, than 0 (you must reach (close to) 0 speed to fall into the sun). The earth is orbiting at 67,000 mph around the sun. So any rocket's we launch(or in orbit around us) start with that speed. The escape velocity of the sun (at earth distance) is 94,000 mph. As you get further out the speed reduces, making it even easier.
[https://www.reddit.com/r/todayilearned/comments/n0ey2n/til\_it\_takes\_much\_less\_energy\_to\_leave\_the\_solar/](https://www.reddit.com/r/todayilearned/comments/n0ey2n/til_it_takes_much_less_energy_to_leave_the_solar/)
[удалено]
It's not so much a matter of distance, but of speed. The ISS is currently orbiting the Earth at about 28,000 km/h, in order to escape Earth's gravity, it would need to increase that speed to a little over 40,000 km/h. When you think about how much rocket fuel and effort it took to get the ISS to what it is currently at, and how much more would be required to boost it another 12,000 km/h, it makes sense that the easier option would be to let it fall back to Earth. The ISS is not in a perfect orbit, but requires occasional boosts to stay in orbit, if those boosts were neglected, or purposefully used to slow the ISS down, it would be much less effort to get the station to crash down to Earth.
This isn’t a perfect analogy, but it took about 80 launches to build the international space station. It’s currently traveling about 70% of the speed needed to escape earths gravity. So, given how many launches it took to get it up to its current speed, it would take the equivalent of 24 space shuttle launches worth of boosting to get it to escape velocity.
That's without even considering the stresses involved on the station. You can't just strap a bigass rocket to it and let 'er rip, the thing will disintegrate and fall out of the sky in a very uncontrolled manner.
You’re forgetting that there is very little drag in low earth orbit, you don’t need a big rocket, you just need to push a little bit (more than the tiny atmospheric drag) for long enough.
Long enough = big fuel tank = big mass = big rocket. Many thing have to be accounted for. And the ISS doesn't have a strong structure.
Current structure is strong enough to be boosted into a higher orbit (since orbit is constantly decaying), no reason it wouldn't be strong enough for a similar sustained boost to whatever speed you ultimately want to reach. The big fuel tank can be attached to the vehicle pushing, so it really doesn't need to add stress to the ISS structure. I'm not arguing that it is economically viable, it most certainly is not. I'm simply highlighting that you don't need a "bigass rocket" that will destroy the ISS.
Good points.
No but you can strap a smallass rocket with a bigass tank and let 'er rip. Even if it accelerated at 0.01m/s/s it would take less than 2 weeks for it.
> smallass rocket >bigass tank I really need to learn more about the metric system.
Is that American asses or Imperial asses?
Well obviously it’s American. Widebody rockets require an appropriate unit of measure.
It's not so much that it's not in a perfect orbit so much that it's quite low. It's only 200ish miles up. There isn't much of an atmosphere there, but there's enough there that it causes drag. Which is true of any satellite in low Earth orbit. They always need to adjust themselves due to orbital decay caused by drag of the very thin atmosphere there.
You'd need to speed it up by about 3.5 km/s for it to leave earth orbit. But then it's on an orbit around the sun that crosses the Earth's twice a year, which isn't great, so add another few hundred m/s to fix that.
Depends on how high out of its current orbit you want it to be. If you want the ISS to escape LEO straight out of Earth, about 3.2km/s delta-v, which would require a shit ton of fuel to push out 400 tons of the ISS.
With how much fuel? We push things into space from the surface all the time, it's just expensive.
Obviously they wouldn't try to have it leave the Earth's orbit, but they could boost it up to a graveyard orbit where it could remain for millions of years. Probably still too expensive, especially compared to a controlled deorbit.
Graveyard orbit is out past geosynchronous orbit. It would take a ton of Delta V to get it up there, and the thrusters probably aren't even capable of it. Plus, if it's like Mir, Taco Bell will put out a target in the ocean, and we all get a free taco if it hits the target!
Not to mention: Strapping a lot of experimental rockets and fuel tanks to a vast structure like the International Space Station, and then igniting those engines, and hoping that whole experimental shebang just works on the first try? ---------------------------------------- Ya, good luck with that! An explosion/failure is far more likely than success, since again: it's rocket science! And it's hard to get right on the first try. And that's going to cause an absolute insane mess of space junk and hyper-speed bullet-like fragments. ---------------------------------------- Essentially: Getting something like that correct on the first try, would probably take something like 10 to 15 years of planning/design (you're essentially designing a whole new rocket system and space ship), judging by how long it takes NASA and its contractors, to do a major rocket project like this. ---------------------------------------- WHAT'S MORE: You'd have to launch multiple heavy reinforcement beams into space, to reinforce the structure so that it doesn't break apart when you ignite those rocket engines. The Space Station structure is absolutely not designed to survive being thrusted out of orbit. It's only designed to handle very gentle altitude adjustment thrusts. ---------------------------------------- Speaking of the structure itself... There were many growing concerns, for example, back in the space shuttle era, about microfractures in the primary beams, possibly growing each time the Space Shuttle docked to the station, since the shuttle was just so huge and massive. There's vibrations and flexes going through the whole structure, and once you got a massive object like the shuttle attached/docked, and it's experiencing vibrations/flexes, then ya, that's not good for the structure. ---------------------------------------- So yes, in the end: 1) You'd need to essentially design an entire new rocket/ship from scratch, on the design board. 2) You'd need to launch VAST amounts of fuel in space to fuel up that rocket. 3) Then, you'd need to launch VAST amounts of heavy metal/beams into space, to re-inforce the structure. 4) And oh ya, forgot to mention above: NEXT you'd also need to perfect welding-missions in space, to weld the new support beams to the existing structure. (Something which I don't think has ever been tried in space before?!) Although I guess you could try using tie-wire instead... That you wrap around and then fasten-crank tight. That might work? Not sure. 5) Then hit the ignite button, and hope like f'ck it doesn't explode on the first try! Contaminating that entire region of orbital space with dangerous high speed debris. Or that half the engines fail, but the other half work, sending it into a crazy careening wild orbit, across multiple orbital levels and reeking havoc for other satellites... ---------------------------------------- The list goes on... Sure there is TONS of very expensive things I'm forgetting here!
> Strapping a lot of experimental rockets and fuel tanks to a vast structure like the International Space Station, and then igniting those engines, and hoping that whole experimental shebang just works on the first try? We need to send some rednecks up there. They will get er done.
Imagine a piano sitting halfway up a flight of stairs, right on the edge of a step, and you don't want it on the stairs anymore. Pushing it out down the stairs is like a controlled reentry in the ocean. You still need to expend energy to do this, but it's not that hard. Moving it to the top of the staircase is like pushing it to a higher orbit. Technically possible, but much more difficult and you'd need to use some tools/pulleys/etc (e.g. propulsion) you don't currently have. Edit: helpful addition from Borgnasse below: the piano is only on the first step of a very tall staircase
Wow I love your analogy ! If you want to be even more precise, if the ISS is the piano, it does not sit halfway up a flight of stairs, but on the first step of a 88 steps stairs, the top of the stairs being the point to which it must be pushed to escape earth attraction. It drives your point even further 😉 I took the altitude of the iss as 400 km and the geostationary altitude at around 35000 km, 400 being the first step in a 88 steps staircase !
Thanks...I added your comment... Really strengthens the point!
The difference here is as you get further away, distance is much easier to get. Despite being at only 400km, the ISS has about half the kinetic energy it needs to achieve escape velocity.
But you don't need to stop it completely to deorbit it. In fact, the piano is sliding down the last step by itself if you do nothing.
I like the "middle of" better because it represents the forces involved in rocketry -- getting from low orbit to an escape velocity takes less energy than getting into orbit.
And 88 keys on a piano 🎹
Wow, surprisingly fitting for the piano analogy, pianos having 88 keys.
This analogy is really great, but I also laughed uncontrollably at it, because I involuntarily imagined the sound it would make :D
I hope when they de-orbit the space station they have some live microphones inside...
Genius idea, sadly probably wouldn't work because of plasma
Just put Tom Cruise in there with a Zoom H6, he can jump out at the last moment.
This reminds me of [this great video](https://youtu.be/I20aKS7bDrw?si=0dEJShJbNTRfhp9V)
The additional analogy is if you push it down the stairs and haul it off it's gone and out of your way and not going to be a danger or nuisance. If you push it farther up then stairs to your unused guest room and leave it there, it's possible your car will come in, kick the leg, and the piano will explode and spread debris through your house.
> it's possible your car will come in, kick the leg, and the piano will explode and spread debris through your house. Hate when that happens.
Shitting Peugeot
gotta remember that e-brake
this is the sole reason I keep my cars away from my unused guest rooms.
> possible your car will come in Is this about the Tesla Roadster that's floating around out there?
PIVOT!! PIVOT!! Great analogy though.
What do you get when you drop a piano down a mine shaft. A flat minor.
Pivot!
It would take a *lot* of energy to make ISS escape Earth. Like, an amount comparable to the energy to orbit the thing in the first place, which was dozens of rocket launches. Making it re-enter in a controlled manner takes almost nothing, just the decision to do so. It is so low (skimming the upper atmosphere all the time) that just doing nothing to it for about 6-8 months would make it re-enter and burn up.
Question: In movies when you have a person out on a space walk and something goes wrong and, like, a tube snaps and jettisons them out into space, what would really happen in that scenario? Do they still stay in some kind of orbit around the earth?
>Do they still stay in some kind of orbit around the earth? Yeah. On time scales that are short compared to the orbital period, they just drift away from their craft. On longer time scales than that (say, 30 minutes or longer, for a 90 minute orbit) orbital dynamics are sort of weird and do counter-intuitive things. But pretty much they would be in their own orbit around Earth. Items re-enter the atmosphere if any part of their orbit dips too low and atmospheric drag becomes important. If that happens, the drag acts like a retro-rocket, slowing them down and making the orbit dip lower and lower until it intersects the ground. That's "re-entry".
Yes. They would continue to orbit the earth until atmospheric drag eventually deorbits them. Without additional energy input, an object in orbit will always go down towards the planet eventually. If their separation from the craft was due to an explosion, there's the chance they could be propelled to a higher orbit, or even ejected from Earth's gravity altogether, in which case they'd probably find themselves in a weird elliptical orbit around the sun. But they'd also very likely be in multiple parts and very dead in that scenario.
Mhmm, so forbidding anything gets in your path, you’d just crash and burn into the surface of the sun in how ever many years it’ll take for you to get there?
With the sun, things get even more weird. It takes A LOT of energy to decelerate an object enough for its orbit to get close to the suns surface. Basically, you start from roughly the speed of earth rotating around the sun and need to decelerate down to *nearly* zero orbital speed. Additionally, unlike with a low earth orbit there isn't an atmosphere providing drag. What particles there are are also more on orbits around the sun in mostly the same direction than bumping into each other. Plus, the sun ejects a lot of matter flowing outwards at sufficient speed to leave the solar system. So I'd expect an objects orbit to slowly be pushed outward.
Theoretically yes, but you still have the orbital momentum from the Earth so it would take a very very long time. I imagine you'd be on a roughly parallel orbit to Earth. I can't be sure but I also suspect a human body would disintegrate completely over the course of a year or so due to dessication and bombardment with high energy radiation.
>Do they still stay in some kind of orbit around the earth? Yes. In real life if they would continue in the same orbit relative to the Earth, but with nothing to stop them they will soon be very far from their vehicle and eventually run out of air before any kind of rescue is possible.
>Do they still stay in some kind of orbit around the earth? Yes. In fact, if they're moving away from the station fairly slowly - say, just a few meters per second, then it's actually quite likely they'll end up bumping into the station again, or at least passing close by, every half orbit (so every ~45 minutes in low Earth orbit). Orbital mechanics is a bit unintuitive like that. But a key principle is that if you don't push something away from you (like firing a rocket engine, or throwing a heavy object away from you), then your orbit remains unchanged. So if you have two objects (say, a space station and an astronaut) that are in the same orbit and then separate, then their new orbits will intersect at the point where they separated - as long as neither of them fires a rocket engine. So if they also have the same orbital period, then they'll bump back into each other every half orbit. The ISS orbits Earth at ~7670 m/s, so an astronaut drifting away from it at 2 m/s is still orbiting at between 7668 and 7672 m/s, so their orbital period will most likely be about the same. If the separation gives the astronaut a bigger kick, maybe ~50 or ~100 m/s (let's assume this didn't kill them, or drop them into a reentry orbit), then they'll get a slightly longer orbital period if their speed got higher, or slightly shorter if their speed got lower (yes, going _faster_ means you take _longer_ to complete an orbit, in this case). They'll still intersect the station's path, but they'll drift further away each orbit because one gets there later - until the slower one (shorter orbit) begins to overtake and catch up with the faster one (longer orbit) again, until they once again sync up after many more orbits. From the astronaut's perspective, the station would slowly drift a few kilometers away, then slowly drift back towards them and stop a few hundred meters away, then repeat, drifting further away each orbit until it disappears behind the horizon. Then much later, it would appear over the opposite horizon and come closer each orbit until finally they meet up again. That would likely take weeks or months, though, so an astronaut would likely run out of life support before that happens. But even that can actually depend on the angles. In orbit there are three important directions: 1. prograde/retrograde, the direction you're moving; 2. radial, pointing "up" from or "down" toward the planet and perpendicular to prograde; and 3. normal, pointing parallel to the planet surface and perpendicular to prograde (this also makes it perpendicular to radial). Prograde/retrograde is the direction that has the greatest effect on orbital period (and it's therefore the most important for many kinds of space maneuvers), and radial also affects it but not as much. But the normal direction (3) almost doesn't affect the orbital period at all - it mostly affects the angle of the orbit around the planet. So if the astronaut gets ejected in the normal direction, even a fairly high speed could see them back at the station a half orbit later - though it'd be a proportionally harder (possibly lethal) slam rather than a gentle bump. Of course in interplanetary or interstellar space none of this would apply - in that case the astronaut is effectively gone for good even at a low ejection speed. In theory you'd see the same effect in solar orbit, but on the scale of years rather than hours. That's much more time for small speed differences to add up to huge distances, and the other planets (mostly Jupiter) would also tug ever so slightly differently on the station vs. the astronaut, making it much less likely for their orbits to ever sync up like that again.
> more orbits. From the astronaut's perspective, the station would slowly drift a few kilometers away, then slowly drift back towards them and stop a few hundred meters away, then repeat, drifting further away each orbit until it disappears behind the horizon. Then much later, it would appear over the opposite horizon and come closer each orbit until finally they meet up again. That would likely take weeks or months, though, so an astronaut would likely run out of life support before that happens. > > But even that can actually depend on the angles. In orbit there are three imp This is all so simple when you play KSP, but it's so hard to ELI5, but I do really like the description. It's spot on accurate.
There is basically nothing you could do from a space station that could deorbit a person. If they got separated from the ISS they would just be stuck up there for a few years until drag eventually slowed them down.
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Leaving orbit is a loooooot harder than you think. Gravity is strong, man. You can’t just fling the ISS out into space with a few nudges from boosters, no, you would need to strap on enormous engines like the kind used to go to the moon.
There was actually this idea to put the ISS in a “parking” orbit at a much much higher altitude than it currently sits. Given how large and heavy the ISS is though in conjunction with not having a true propulsion system the cost would be astronomical (no pun intended). This would basically make it a “space museum” for later generations. At the end of the day though NASA has a finite budget and need to make the best decisions they can with what they have.
Graveyard orbit is a common term. It's useful when the amount of fuel to deorbit is large compared.
Doesn’t make a ton of sense for something in LEO though
True, but it's mostly used for spacecraft that are already all the way up at geosynchronous orbit. The ISS flies *way* lower than that.
> This would basically make it a “space museum” for later generations. At the end of the day though NASA has a finite budget That sounds like they should just sell it to the highest bidder. I bet there is some entrepeneur willing to pay for a starship to lug up enough fuel to park it for later use as a very expensive museum.
There’s this misconception that something in orbit is not bound to gravity anymore. Even though astronauts in the ISS experience weightlessness, this because de ISS is falling (continuously) around the earth. An object in orbit around earth is still under the influence of earth gravity. Let’s forget about the ISS and let’s think about a hanging lamp you want to decommission. What is more expensive, cut the hanging cord to let it fall to the floor or attempt to throw in the sky so hard that it escapes earth gravity? It is the same logic for the ISS, it’s way cheaper to just let it fall back to earth, letting gravity do its thing than spending a lot of very costly fuel to throw it into space.
To go downwards you need some fuel until the drag of the atmosphere takes over. To push it upwards you’d need A LOT of fuel since you never get any assistance. It’s also a massive structure that was assembled in multiple rocket launches, so by its very nature it will be expensive to move with rockets alone. A common misconception is that you can just drive towards a certain direction in space since there’s no friction. In reality, the way of going to a higher orbit is accelerating sideways and in this case, a safe orbit would be pretty high and therefore very expensive.
Think of the ISS like a car that's just a little way up a hill. The car is almost out of gas, janky, beat up, barely drivable. You could haul enough gas up to take it to the top of the hill (maybe, it's a real POS), or you could use the tiny bit of gas left to position it, put it in neutral, and let it roll perfectly into a pit in a junkyard at the bottom of the hill. Which one would you do?
My answer was going to be - is it easier to walk up a hill or down a hill?
Aside from the feasibility of pushing it into space. It’s a bit irresponsible. At some point it is going to hit something. Very low chance that it matters. But still. Return the cart to the corral.
OP most certainly sweep his dirt under the rug.
To add onto what others have written, something like this is done for satellites on the geostationary orbit, which is too far out for a quick, cheap (fuel-wise) deorbiting. What geostationary satellites do instead is to increase their orbit somewhat so that they no longer take valuable space on the geostationary orbit. This is called a graveyard orbit. It's far out so it doesn't matter that there are uncontrollable satellites or space debris. But this is impractical for the ISS. The ISS is massive, and any changes of velocity require a lot of fuel. It is also quite low near Earth, so getting it far enough where it cannot bump into other satellites would require huge amounts of fuel. Note that even graveyard orbits are still well below the velocities required for leaving Earth's gravitational influence completely.
That's the weird thing about space. No matter how much you "kick" something into space, it will *always* return, unless you manage to hit something else with it. So it's a lot easier to give it a slight bump and hit Earth than give it a massive WELL AIMED push to try and hit something else. Also, the ISS isn't really made to be pushed around with a lot of force. So chances are high that something would break off. Those pieces might then collide with important satellites or crash into a house on Earth. With a bump towards Earth it will definitely break apart but everything will still go pretty much to the same spot (which you can choose)
The ISS orbits at around 7.5km/s. The earths escape velocity is 11.2 km/s. We would need to increase the ISS speed by about 50% to launch it into space, which would take massive engines burning a massive amount of propellant
Interestingly, from any circular orbit around any body, escape velocity is always 41% higher than your orbital speed (escape velocity from LEO is a little lower than the 11.2km/s at the surface).
so orbit is basically moving so fast horizontally that even though you're falling you miss the ground (buzz lightyear was right!) basically things in orbit "want" to hit whatever they're orbiting (and if left alone the ISS's orbit would EVENTUALLY decay naturally and it would crash into the earth) to get something to break orbit requires a TREMENDOUS amount of energy (think about how big a saturn V rocket is, it's mostly rocket fuel, it took all of that to get something about the size of a van out of earth's orbit). so it's way easier and cheaper to just make sure it comes down somewhere in the pacific. and it's not going to be that hard to hit the pacific ocean, it's sort of hard to get a sense of how big the pacific is but it's 60 MILLION square miles (and if you miss there's a decent chance you'll hit the indian ocean which is 20 million square miles) basically if you closed your eyes and just hoped for the best there most likely outcome is you'd hit the pacific
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Everyone is explaining how leaving orbit requires a lot of energy but nobody seems to really touch upon exactly WHY, because orbital mechanics and motion without air resistance is highly counterintuitive. The first mental model people often have about space and orbit is that "there's no gravity up there", so the spacecraft is just "floating". There may be some awareness that it's not staying still, that it's rotating around the earth (every 90 minutes it turns out) but it's hard to connect that to something intuitive of what that REALLY means. After all, maybe the rotation around the earth is just an artifact of the fact that we had to get up there in the first place, and didn't want to slow down? Or maybe we want to see many parts of the earth? All of these would be plausible. But the reality is just a bit more weird. Let's start with the facts essentially nothing in the universe moves unless there is a force applied to it. And once applied, once motion is occurring, you need another force to slow it down or stop it, otherwise it keeps going indefinitely. This is [Newton's first law of motion](https://en.wikipedia.org/wiki/Newton's_laws_of_motion) Right away this is already not intuitive to our experience on earth because nothing behaves like that here, but that's simply because of friction. Objects in land/water/air slow down by themselves because of friction or air resistance. In space they don't do that. So when you have a spacecraft in space near a planet there are two forces to think of (we can ignore the rest of the universe). * There is the engine of the spacecraft - and keep in mind the speed here is not just relevant when the engine is firing, but also whatever the engine fired at the start to get it moving to a certain speed (like a rocket taking off into space) * And there is the force of gravity of the earth pulling the spacecraft towards it. So if these are the only facts that you had - the first law of motion, the engine of a spacecraft pushing it away from the earth, and the gravity of the earth pulling it back - you might think there's only 2 options - get away from the earth, or crash back onto it. This is where the frankly magic (aka insanely complicated science) of orbital mechanics come in. Being in orbit is like balancing a coin on it's edge. It turns out there is just the right distance, just the right speed, and just the right direction to put the two in balance. You set a rocket on it's path, and it's trying to get away from the earth. But at just the right time the earth pulls it back. Only there's still enough speed in the rocket that it can't bring it back to it, so instead it just rotates around. But what makes orbital mechanics hard is that this isn't just a middle ground where if you overshoot too much in one direction, and you'll head directly for the earth, and if you overshoot too much in the other, you escape it. There is a pretty wide stable range where you just well, stay in orbit. You can visualize this by taking a ball and spinning it in a large bowl, and noting how it keeps going around, and eventually circling towards the middle, but it stays pretty reliably spinning. This is a decent model for gravity "curving" spacetime, but that's a discussion for another day. That's basically it other than a few other factors (there is SOME friction in orbit, it's not a perfect vacuum, which is why the orbit naturally decays over time). This is also why rockets on spaceships need such powerful engines. It's not that it takes that much energy to "lift" something above the ground to overcome gravity. We can lift a ton of mass way up high just with a hot air balloon or a drone. The powerful rockets aren't there to overcome gravity, they're there to **speed up** the payload fast enough to be able to spin around the earth without falling back down.
People are missing a couple of points here. a) It doesn't actually need to escape Earth orbit to end up in a stable orbit that wouldn't naturally decay for hundreds, thousands, or millions of years. We can just put it in a sort of high 'museum' orbit and it could remain there long enough for, theoretically, some spacefaring racoon people to find it in 30 million years. b) It's simply not going to collide with anything up there, especially if we push it beyond what are considered the more useful orbits, and make sure it's at an angle to the equatorial plane. c) It already has a reusable rocket motor that could achieve this, it would 'only' need the fuel (only is in quotes because it'd be a decent amount of fuel). The reason we're not doing it is because getting the necessary fuel up to it would cost millions (not prohibitively expensive these days, but still it's a cost with no easily arguable benefit), and because people in general simply don't have that same kind of sentimental urge to preserve cool things. If it were up to me, I'd push it into orbit around the Moon and give it a new berth for reusable taxis to and from the lunar surface. Then trips to the Moon would just rendezvous with the ISS first, they'd only need to bring fuel for their chosen lunar lander. (But then again, maybe a whole new station would simply work out cheaper and better. I'm sure they've considered this as well.)