Anyone want an International Space Station? Slightly used NASA expects to spend around $1 billion to deorbit the International Space Station as the orbiting laboratory reaches its end of service in the 2030s. A report [PDF] released this week shows NASA will continue to support projects on the ISS, but is also looking towards building a new space lab and retiring the current model …
Why de-orbit *anything*?
The stuff going around and around the planet is *mass*. It can be cut up, sorted and recycled as bits of newer, more magical and *better* habitats.
It took oodles and oodles of go-juice to get that stuff into orbit. We should be considering *not* wasting all of that effort.
For the short-term, we could just attach a few little engines and boot the ISS into a very high, possibly 24-hour parking orbit where she would be safely stored for ages and ages until we needed the metals, plastics, moulds, fungi and human wastes that she's made from. There's no hurry, ion engines would do. We could save loads of money on not lifting up that which is already there. Which brings up the point about "waste dumps".
If NASA are serious about long-term manned off-world activities, the poops made in the ISS should be saved for that far, far distant time when humans have city-farms in high orbit. True, the ISS crews probably won't make even a ton of waste over the lifespan of the station but that's a ton that would never need to be lifted from [then subsequently dropped back onto] the planet's surface.
NASA are, and always have been, extremely myopic, little-picture guys with poor grasp of long-term economics.
With foresight, even MIR could have been a valuable resource. Not, perhaps, as itself but certainly as scrap.
This one doesn't rotate and it has had all sorts of problems like leaks over the years, and you want to make it more complicated? I don't think we're ready for a 2001 type space station yet, plus one of the reasons we have it is to do stuff in microgravity which rotation would defeat. A rotating crew quarters might be useful to reduce the negative effects of zero g on the human body, but that's something we are interested in studying as well...
I don't see a spinning structure as any more complex than a stationary one, other than the need to rotate any incoming craft at the same rate and dock at the hub. Which may lead to a design for an exit in the side of an incoming craft rather than the nose?
It'll make it heavier, sure, but that's just engineering; it's effectively a suspension bridge, no? Or a bicycle wheel? It needs to be able to support its own weight against whatever value is chosen for effective gravity but that's not difficult.
Hmm, if only they'd carried all those shuttle fuel tanks to orbit and joined them nose to tail.
The downside of a rotating station is you only get to have two docking ports at the axis. The ISS currently has space for 8 at once. At least one is the "lifeboat" so there's pretty much always going to be at least one docking port in use, leaving only one "spare" for cargo and crew missions on a rotating station. To remove that limitation would require a hub and spoke system with bearings, hugely more complex and risky since you then need some way of either spinning up the hub with ships attached or some other clever way of moving from the non-rotating hub to the spinning bit.
On the other hand, if and when Starship flies, the lifting capacity and reusability and therefore vastly lower costs will probably change the game completely.
Mir was tiny compared to the ISS. The ISS is big enough for large chunks of it to make it to the earth's surface, which is a big hazard to anything underneath. Deorbiting the whole thing in one go is out because it would be too unpredictable in its "flight". It has to be dismantled first probably into individual modules and each deorbited separately. Each part will also have to be powered so it can be controlled where it enters the atmosphere and intimately ends up. I don't know if each module is equipped to do that so that might mean missions to fit thrusters to each module.
The deorbit of the last ATV (ESA's Automated Transfer Vehicle) a few years ago was heavily instrumented to gain understanding of how the ISS modules will behave when deorbiting (the ATV was similar in size to an ISS module).
It's not a simple job and I suspect a lot of the costs are the space launches required to go up there and sort it out. It's not a simple case of the last astronaut to leave turning the lights out.
I didn't suggest deorbiting it all in one go.I sad detach each module and push them out of orbit using Canadarm2.
The largest module is Kibō afaik, but that is itself made up of modules, the largest being 15,900kg. Which is smaller than a long list of satellites and stations that have been deorbited without extra expense or danger. Eg. Salyut 1 was larger and burned up over the Pacific.
I just can't see what will cost $1bn. It seems like fairly typical NASA overspend.
I don't think Canadarm would be able to give the modules enough delta-V to de-orbit them. They would just end up in an orbit very near that of the remaining pieces. (Also, it would impart equal and opposite momentum to the bit the arm was attached to.)
The simplest method would be to send up capsules to dock with each piece and use their engines to de-orbit, which sounds like what they're planning. I assume they have a good reason for wanting to come up with a new craft (maybe more taxpayer $$$ for the contractors, or am I too cynical?) rather than using an existing one (the Russians will probably just use Soyuz for their bits).
"I don't think Canadarm would be able to give the modules enough delta-V to de-orbit them."
I believe you are correct about that. Some Googling puts a deorbit figure at about 90 m/sec of delta-v (about 200 mph in freedom units).
And like you pointed out, there's that whole action/reaction thing going on.
Granted, we could separate a module, nudge it away with Canadarm, and continue to boost the ISS orbit on a normal schedule, and the separated module's orbit would eventually decay. That won't result in a controlled deorbit of the module, though.
Would be interesting to see some rough math for what it would take to deorbit the ISS all at once (you'd probably need an extremely steep angle of entry to avoid having the station or parts of it gliding to unpredictable areas, so the change in velocity would need to happen quickly = large acceleration = large forces). I'm guessing that it would take an obscene quantity of fuel, an impractically large rocket, or the resulting forces would rip it apart (or all of the above).
Clearly then, the answer is to fling the modules away one at a time in the "deorbit" direction and use the reaction to push the rest of the station in the "keep in orbit" direction![1]
With luck, we can get a decent lump of the ISS into a transfer to Lunar orbit[2] and have it ready to become part of the Lunar Gateway Orbiter before Artemis II gets there.
[1] this probably won't work.
[2] this almost certainly won't work; not unless they add a lot of bungee card to the Canadarm and turn it into a proper Beano-style catapult[3], modules for the flinging with.
[3] also need to send up a really large pair of shorts, so that the catapult can be properly stowed in the back pocket until it approaches the Moon and needs to use it again for the lunar orbit insertion fling.
If there are any monitoring instruments onboard, then I would love to see it go towards the sun. Instruments function as long as they are able, sending telemetry back. Then the lot melts like hot solder.
How much extra boost is needed to lift it out of Earths gravity? After that, get the right trajectory and not much would need to be done.
"How much extra boost is needed to lift it out of Earths gravity? After that, get the right trajectory and not much would need to be done."
In short, provide something like 30 m/sec change in velocity and it would fall into the sun.
It's more complicated than that, but simply put, you're not going to launch the ISS into the sun with our current technology. Change in velocity is much more important than the direction (well, much harder to deal with, anyway), and that much change would require a fleet of Starships just for the fuel. IIRC it would actually be easier to send it off to deep space.
Being that this is El Reg, there are more than a few people here who can hopefully explain better than I can.
Canadarm isn't really able to "fling", and of course lowering the orbit of one module would raise the orbit of the rest, making each successive module harder to "fling".
I expect disconnection and individual controlled reentry is the plan - but someone might come up with something more interesting.
Basically you can change orbit slightly, and things will de orbit, but not in a controlled manner (not important for small things)
Fling was obviously a hyperbolic choice of words. Nudge or push would work too.
And the rest of the station would still have its own manoeuvring thrusters so it being pushed in any direction shouldn't be an issue.
And I think the "not important for small things" is key here. None of the modules is individually large enough to pose a danger from what I can see - each module is smaller than larger objects that have been deorbited in the past and have burned up just fine.
At which point you don't need to do anything - just split the station up - no need to fling anything anywhere, it will de orbit, and if you're so sure all the pieces are sufficiently small... no harm done.
But if you look at what landed from skylab... it was things like individual oxygen tanks that landed, and whilst we were lucky that that was deposited in a pretty isolated area (albeit less isolated than the deep ocean) you don't want to take that chance with the whole of the ISS.
You want to be very deliberate about where you deorbit each piece.
Skylab was considerably larger than any of the individual modules in ISS.
There is a pretty long list of objects larger than any of the individual modules of ISS that have been deorbited, without extra equipment or expense, and burned up in the atmosphere, or landed in oceans as planned...
I have not said to deorbit the "whole of the ISS", in fact I've repeatedly said to split it up.
Yes skylab was, but it didn't land - components did... and equivalent components exist on the ISS.
I even said split it up, you just don't need to throw it apart, orbital mechanics will separate the modules and they will probably come down across such a long reentry path that it's inevitable that a substantial piece of something will land somewhere populated.
You can deposit them on the planet - but there are very specific locations where things get dropped... you don't just let them fall randomly (unless you're china)
We have quite alot of water, and quite alot of water thats a very long way way away from anywhere we use - that's what we aim for... the risk is then minimal.
And everyone else does spend money to deorbit things in the correct place, but nothing is quite as large and complex as the ISS, which didn't (for reasons that should be obvious) have every module equipped with propulsion systems etc.
"burned up" doesn't mean burned up completely. There are still a lot of bits and pieces that would survive in large enough chunks to cause harm when they hit the ground. Standard procedure is to deorbit such that the debris lands in the ocean, hopefully not hitting anyone on the way.
"Canadarm isn't really able to "fling", and of course lowering the orbit of one module would raise the orbit of the rest"
But the ISS needs orbital adjustments regularly from one of the docked spacecraft to keep it up there otherwise it would come back down anyway. So flinging a module off will push it up a little and natural orbital decay will bring it back to where it started, saving the fuel money normally spent of maintaining orbit :-)
Yes, I know, it's all rubbish...but...ya know...just being a bit nit-picky :-)
Orbital mechanics are weird. You can't just throw stuff at the planet and expect it to hit. 45 minutes later, rather than being on its way to fiery destruction, it'll be *above* you.
Draw planet Earth in the middle of a piece of paper, and draw a big circle around it to represent the ISS's orbit.
Imagine you throw something from your space station when you're to the left of the planet. You're following the circle of the orbit, and whatever you throw out is also following this circle. So you're adding a little rightwards motion to the object, towards the planet. That's good, it'll carry on heading that way, yes?
You're a long way from the planet, so the object won't reenter just yet, and continues on its orbit, just slightly further away from you. Now you're a quarter of the way round your orbit, near the top of the piece of paper. The additional motion you gave the object was to the right, and laws of motion being what they are, is still to the right. So now from your point of view is now moving ahead of you, and not towards Earth.
Another quarter of the way around your orbit, you and the object are now to the right of Earth. The object is still moving to the right relative to your orbit, so now it appears to be in front and moving above you, away from the Earth. As you orbit around, this dance continues.
So chuck something out of the ISS, and it'll move away from you, but stay in pretty much the same orbit.
It's hard to hit the Earth. It's even harder to hit the Sun.
"You're following the circle of the orbit, and whatever you throw out is also following this circle. So you're adding a little rightwards motion to the object, towards the planet."
I'm not saying throwing anything is a workable idea, but theoretically speaking wouldn't it be better to throw it behind you? Then it slows down a bit and the orbit decays a bit.
Excuse my child-like naievety but can't NASA just gaffer tape a couple of Standard fireworks to it and shoot it off into the inky-black beyond? Seems like it would be considerably cheaper, especially if done around late October/early November. Bonus points if it can be filled with some of the human flotsam/jetsam from the planet below before pushing the Goodbye button. I'm sure we could help suggest some names of 'volunteers' that could be putin...
For a 400 tonne object in LEO you would need to increase it’s velocity 3.5 times which is about 5,000 times the kinetic energy it currently has! The S-IVB (third stage of Saturn V booster) needed over 100 tons of fuel to get the 28 ton CSM to the Moon, so for ISS you need to get half a Saturn V into orbit, which might need two Saturn V’s to get it there! That is a big and expensive firework!
Not exactly. There are two ways of doing things in space, short and fast or long and slow
In theory we could fit some ION thrusters on to it or even a large mylar sheet covering a large surface area. Yes it would not be quick, but it would get there eventually.
Methinks a good XKCD question...
Trouble is we are going to be expanding that fuel and more setting up either ISS’s replacement or forwarding modules to build similar facilities further out.
Personally, I suspect the scientists and engineers need to get their hands on ISS so as to better understand space weathering etc. whilst 25 years in space is a relatively long time, we need to building space stations that last significantly longer.
I can imagine it now.
Rocket sends the ISS off into the "inky-black beyond".
Several years later very angry alien arrives with interstellar lawyers and written off "flying saucer" in tow wanting to know who is responsible so he/she/it can sue their asses off. And the thing that pisses him off the most - it's cost him his no-claims bonus.
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Orbital mechanics are complicated, you need engineers to calculate things right.
I think that gaining altitude is a lot more costly in energy than losing altitude, but I am far from being an authority on that question.
I'm pretty sure that, if NASA wants to de-orbit the ISS, it's likely because that will be the least expensive option.
In terms of orbital mechanics it's actually easier to raise an orbit, than lower it (because you're getting further away from the Earth and the effects of it's gravity lessen). The big difference though is that as you reduce your altitude you get more and more drag from the atmosphere which does the work of slowing you down for free.
So to put the ISS (say) 100km further up would take a lot of energy, but to bring it down 100km to the ground, you only really have to get it into the thick part of the atmosphere.
Of course, then you have to work out where it's going to land. Predicting where a uniform shape like an Apollo or Soyuz capsule will land is tricky but possible (within a few miles). Predicting where a big complex shape like the ISS will land is much more difficult. Even aiming for something as big as the Pacific ocean is tricky.
Also tricky is that the bit with the motors on, the bit with the communications system and the bit with the solar power for the motors and communications system are all on different bits that will be become dynamically disassembled as it starts to re-enter.
It's an interesting problem how you program the re-entry with the path becoming unpredictable just as you lose the ability to control it
"Can someone explain why they have to decommission it at all?"
The Russians want to pull out of ISS and make their own new space station. Not sure if they want to de-orbit any Russian modules or just leave them connected and let Uncle Sam sort it out.
And the Americans know that the ISS is wearing out, both internally (after many years of human occupancy and little/no spring cleaning) and externally...so they do not want to leave it unmanned and they do not want anyone inside to be at risk.
"...but it would still need a strap on Saturn 5 to get things in motion."
I'm sure they could use a stage from the SLS and use this to nudge the ISS higher and over time it'll break free.
Or get Tommy Lee Jones/Clint Eastwood to strap some PAMs to it:
https://www.youtube.com/watch?v=uu4tB54Uw5I
Yes and this is the saddest bit. It is going to be difficult to fund a replacement.
Obviously Russia won't be asked anytime soon and China are unlikely to join any future international missions.
That leaves NASA and ESA, but neither really have the funding or political will to do another one, so this could be the end of long term space habitation for a while, unless some of the private space hotels that keep being mooted come to pass
If so it will be a great loss to manned space science and a serious impediment to any manned Mars mission
I think China would be interested in joining - but (in my view) the relationship would be an unhappy and untrustworthy union from both sides - it would just be a microcosm of both sides continually spying on each other ...
The US wouldn't consider one due to China combining their military resources with the rest of their governing infrastructure - although this doesn't explain why the USAF were so quickly able to develop the X37B on their own without the help of NASA .. and my my - doesn't the X37B look like the Space Shuttle?
Recent events on the space station (micro punctures found etc) are evidence to an deteriorating relationship between Russia & the US for example - I just think more of the same would happen
I think what's more likely is the US will establish a space station in collaboration with private industry (American of course) for their own use - the rise of American imperialism as it were
China already has their own Heavenly Palace anyway.
I wonder if it's a coincidence that they gone from "revolutionary" names to mythical-sounding names for their space hardware at the same time Pooh Bear is angling for the position of Emperor-for-life?
It seems a waste to spend another billion when we already have nuclear ICBMs that tragically never get used. Just fire one ahead of the ISS so it gets pushed retrograde and smashed into smaller pieces that will burn up before they hit the ground. Nothing could possibly go wrong and the money has already been spent.
They consider it end-of-life...which means it is no longer considered safe for people by people with wildly excessive safety margins. That's fine. So why not sell it? There are companies out there that will buy the station, refurbish it, and use it as a base to build their own new station.
Or why de-orbit at all? Use some ion thrusters (low thrust, but long term) to increase the orbital velocity, boosting the height of the orbit and taking it out and away from the Earth. Keep those firing for an extended period and you could push it into the Sun or impact it with one of several planets that are out there floating around.
For that matter, why not use it as the base the build a new station rather than just junking it and flying a new station (in pieces) up there? Though if Starship proves itself, lobbing large chunks up is going to become way easier.
And if we stay on the "sell it off" model....sell it by pieces. Those solar panels are still working, are you telling me that someone won't want to buy those to use on their own orbital startup? It just seems like blinkered thinking.
"We MUST de-orbit it! There are no other options!"
There may not be any standard options...but times are changing and space is becoming a place we can actually see more activity in. Things could be very different within the next 10 years.
There have been other options looked at. Some private companies have suggested taking it on, but I don't know where that went. Russia were making noises a few years back about removing their modules and reusing them.
Boosting it up higher isn't really a solution since the issue is the longevity of the structure and parts itself rather than where it is. Boosting it up up and away and into the sun isn't on the cards either for reasons cited elsewhere here, like the amount of fuel required to get out of earth's gravity well in the first place.
Years ago, the ISS was slated for decommissioning early 2020s, so it's already on borrowed time. I'm most sad that when it does eventually go, if we aren't living in cis-lunar space by then, that will the be end of permanent human habitation in space, for a while. The end of one era and a pause before the the start of the next.
"if we aren't living in cis-lunar space by then, that will the be end of permanent human habitation in space, for a while."
If by "we" you mean America and a few others allowed to be guests up there, yeah. If by "we" you mean humanity, China are happy to keep the place warm for the rest of us with their manned station. I suspect for that reason, the US will actually want to replace ISS ASAP, if only to not be seen as in 2nd place to the Chinese. I think we can discount the Russians for a long while now and other countries aren't really up to manned flight yet let alone lofting their own space stations apart from ESA and there doesn't seem to be the budget or political will to go that route alone.
Power: same place as the rest of the ISS gets its power[1], the great big shiny thing over there.
Reaction mass: send up a bottle or two already attached to the thruster, same as always; they work by sending out not all that many ions per second, but sending them out *really* fast.
[1] say 1 kW per ion thruster, with the ISS generating aprox. 80 to 100+ kW; presumably also shutting down as much of the ISS as possible (guessing the place wouldn't have a full crew onboard).
Can't see this happening[1], sadly.
[1] the lovely blue glow notwithstanding.
"will also be responsible for disposing of their own parts safely"
Somehow I very much doubt that Russia will be doing much about the ISS any time soon, it seems to be a bit more preoccupied by Earthly matters at the moment.
NASA is going to have to shoulder that burden, I fear.
MIR was a shithole and a deathtrap by the time the Russians finally decided to burn it up. You can only maintain something for so long before essential bits can no longer support operation. Even swapping out a whole module is nigh on impossible. Most of the interconnecting hatches are strung through with loads of pipes and cabling so just shutting the door between modules would be almost impossible without compromising all sorts of systems.
Given the cost of putting it up there, the least they could do is turn it into a Heinlein style asteroid mining second hand shop. That way when you are in fancy ISS-2 and you need a left handed widget, you can jut pop a jetpack on, scoot over to Sam's discount scrap metal and parts' and save yourself the round trip back to Earth. In fact why not use it as a base for space junk collection missions to clean up all the assorted mess left behind by previous missions.
"why not use it as a base for space junk collection missions to clean up all the assorted mess left behind by previous missions."
The ISS is too big to manouevre so as to change orbits in order to clean up any oribital fragments that are in other orbits (ie higher or lower for instance).
Plus actually grappling any larger parts will be tricky when most things are orbiting at 25,000 MPH. And collecting smaller parts will be almost impossible as they are difficult to find and almost impossible to catch.
"The ISS is too big to manouevre"
To be fair, the other AC did say "use it as a base". It wouldn't be the ISS changing orbit, but some other vehicle ("space tug" as mentioned in another comment).
With the ISS there are limited options. Some of those limitations are of our own choosing, i.e. we are using a hub-and-spoke model of operations. At some point we need to switch models, people advocating for intra-orbit operations are just thinking ahead. No harm in that.
>They binned the shuttle prematurely...
With a 40% fleet attrition rate, some would say it wasn't binned soon enough.
Don't get me wrong, spaceflight is not without risk. The shuttle program was built upon a design that is now 50 years old. NASA never operated it as a completed space system, it was under constant refinement. As with all experimental designs, sometimes the foundation gets so old that it is necessary to extract the lessons learned and return to the drawing board. I think that is the long term phase we are in now.
I read what NASA says about boosting, and I'm not buying it. We don't have to solve this problem, completely, today.
I am quite surprised at the claim that today, with the "no more missions" option, that the ISS will deorbit itself as soon as 1 year from now. If we change that to 100 years, then we can allow technology to advance, and we can solve the problem much more cheaply then. Throw in compound interest of 2% (for 90 years), and we're looking at a 6x cost savings even without technology advancing.
Start by separating anything small enough to come down by itself safely. Converting those solar panels into orbit-boosting sails. This might require an attitude adjustment & the creation & installation of new engines. Then, send up boost missions to get it high enough that by tacking the solar wind, we get to a 100+ year-safe orbit. Profit.
(I am NOT suggesting that we operate the solar panels as solar sails for a century, just get to a century-safe orbit. Then roll them up.)
My understanding is getting approval to send something to orbit includes your plan on how it will be decommissioned at end of life.
Are we sure we didn't already spend a bunch of money for a decommission plan back in the 1980s for this exact purpose?
There are problems with using plans from the 1980s, including (but not limited to[1]):
The ISS was a lot smaller and a different shape back then *but* a number of the plans were way more ambitious than was actually realised, including IIRC a desire to have lifted it further out already. So plans from then wouldn't match the physical reality of now.
The old plans are unlikely to have taken into account the loss of Shuttle without some expected replacement, let alone the long period that the USA had no man-capable lifting at all. No matter whether the plan was to go up or down, in pieces or one big lump, it likely made assumptions about what could be lifted up to help.
Geopolitics have rather shifted again. Imagine if the old plans assumed that lumps of any part of the station could be safely dropped onto a suitably empty part of the Russian Steppes now that we are all friends again...
[1] i.e. there are far less crude representations of the problems than are given here
Unless the orbit of a replacement space station is going to be different, why would we build a new one from scratch?
Launch a module for the new station. Connect it to the old station. Leave enough propellent in the launch vehicle to start a controlled re-entry. Attach it to a used module from the old station. Dispose. Wash, rinse, repeat.
Wouldn't this eventually result in an entirely new station & old station disposal at the same time??
Seems like it has a 75% chance of landing in the Ocean, Antarctica or Australia or Siberia. And a miniscule chance of hitting me personally, and if it does hit someone they get the privilige of being the first person to be killed by falling space debris and all the posthumous fame that goes with it.
Instead of destroying it, equip it with some slow burn boosters and deorbit it out of the solar system in the direction of alpha centauri. That would be fascinating for some future race to discover a million years from now. It if we're lucky it will crash on somebody else's planet.
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