Why would we ever de-orbit the ISS? It took far more money and effort to get it there than it takes to operate it. The long-term value of ISS is unclear, but so is the long-term value of going to the moon or Mars.
Imagine if the people who founded Jamestown said, "hey, we're ready to start moving deeper in the continent, so let's burn Jamestown and push it into the ocean first." Why give up a beach head?
Our reach on single missions is constrained by our rocket size. Therefore to do bigger missions, we will need to assemble and supply spacecraft in space over multiple launches, as we have assembled the ISS. If nothing else, the ISS would be useful for "worker housing" during such assembly projects.
For the same reason that they de-orbited MIR it will eventually outlive it's purpose.
The modules have a life span, the ISS's mission has already been extended beyond it's original scope, eventually it will come to a point where you can not maintain it and it actually becomes a risk to the astronauts (we didn't had major incidents with the ISS, MIR had a few including a fire, but no major casualties, but after nearly 20 years things can start to break down and a catastrophic failure can very likely result in loss of the entire crew).
The ISS is also limited in terms of what you can bring to it, what type of experiments you can run and how can you extend it so in some sense it limits our capabilities.
When something outlives it's purpose sometimes it's best to discard it because having it and investing resources into it prevents you from expanding and building something new.
We'll eventually have to build a bigger station that could be used for bigger experiments like micro gravity sustainable agriculture, industrial manufacturing and more. As well as potentially actually simulating gravity and other things.
Ideally you'll also want a space station quite further away from earth like maybe a 1/3rd of the distance to the moon which can be used as a launch platform and a future space dock.
Projects like that are going to be very expensive and giving up on the ISS could actually release quite a bit of funding as well as drive the need for a new space station because "well we got the ISS do we really need a new one?" is quite often used as an excuse just like orbiter development was hindered due to the shuttle being in operation for so long.
well the idea that is built with modules should imply that we can swap out the pieces as they age and as the mission changes.
if anything the real reason to abandon the ISS is the same reason we needed to abandon the shuttle program. Nostalgic money pits tend to stick around preventing progress and investment in new and better systems.
I still think one of the best things to happen to NASA in the last ten plus years was having the shuttle program shut down. Yeah it lead to years with lack of capability but it was that shuttle which held back such development and others have stepped in.
I would prefer to get to the moon, having a solid surface under you would have some great benefits, let alone being able to dig deep and hide.
You must remember that a space station is not something like an Army fortification or a building which stands by itself or require very little maintenance, which could be done by a stationed unit.
* The ISS is actually falling back to earth and needs to be lifted from time to time. You need fuel for that.
* The personnel must be changed frequently (too much time in microgravity is harmful to the body). You need to take people in and out.
* The station itself is very little compared to a building. You can't store years of supplies there, just 12 months or so. You need to send up supplies.
So, you must send fuel, people and supplies very often to the ISS. This is very very expensive.
So, it comes a time where you should consider shutting it down or keep using it.
Those are general arguments against pretty much any long term space habitat and they are completely wrong.
The ISS is constantly supplied and refueled that's not a reason why not to maintain it, it's an argument why we should not have built it in the first place which is a very silly argument to make.
We need space stations the more the merrier, China and India are getting into the game, Russia wants a new one of their own, and the public sector is also looking at such platforms for everything from micro-gravity manufacturing of drugs to space hotels.
The argument that people in favor of decommissioning the ISS should make is we need a bigger, better, further away one that we could use to go cheaply to the moon, asteroid belt, mars, and the Jovian and Saturnian moons.
> The argument that people in favor of decommissioning the ISS should make is we need a bigger, better, further away one that we could use to go cheaply to the moon, asteroid belt, mars, and the Jovian and Saturnian moons.
That is the answer to my question. Should we sink the ship because it is old and we have no use for it or should we sink it because we need another one and can't bear the cost of maintaining two?
If someone is willing to use it, then they must pay for it's maintenance. For NASA it's mission was accomplished, and it's time to move on.
Replacing all of the modules including the nodes would cost as much as building a new station.
The specifications are limited, there's a limit to the mass of the modules that can be connected to the nodes (torque is quite real ;)) and considering we don't have the space shuttle to assemble new modules easily (with the exception of Zarya, Unity(node 1), and Zvezda all modules and large parts like the Solar Panel arrays were assembled with the use of the STO) so at best you'll end up with an ISS redux with the same limitations to size, mass, power generation and module compatibility as the current one has.
We need to be able to build bigger modules for bigger experiments, we need more power, we need it to be higher to further avoid atmospheric drag and to be used as a launch platform for further experiments.
There are various proposals for both low orbit space stations like the Russian OPSEK which will be recoverable, and various future uses for the ISS* including using Node 4 and some of the ISS modules for the EGP which will be a refueling station parked around E/M L1 (approx half way to the moon).
The EGP could be build on the existing ISS and launched to L1 since it will have a central node and a service module additional modules even a habitat module could be later added.
* Please note that this will not reuse existing ISS modules in orbit but will reuse built/planned unlaunched parts like Node 4 and Zvezda 2.
These are good points. If I could, I'd revise my post above to say that we shouldn't de-orbit the ISS until we've used it to build something better.
MIR did not de-orbit until the ISS was well underway. More importantly, while building the ISS we had the Space Shuttle, which was like a temporary space station in terms of its habitat. The Space Shuttle pressurized volume was about 75 m^3, and it had an airlock and a big robotic arm.
In contrast, every orbiter currently under development is a little capsule without either. The SpaceX dragon is only 10m^3 of pressurized habitat, and every other is within 2x of that. These are ferries, not platforms for long-term construction projects in orbit. The ISS is the only option for the foreseeable future.
So I hope, if we want to build an interplanetary spacecraft or more-permanent space station, that we find a way to leverage the ISS to reduce the cost and effort.
The 'nails' in this case are dollars in a budget. The ISS consumes a very large number of dollars on an annual basis, and 'burning it down' would free those dollars up for other purposes.
The ISS is more Russian than it is western. The West has contributed more money to it, but Russia was an essential partner and contributed most of the core technology due to their experience with Mir.
Regardless of that, while RT has its biases, do you really think they extend to a mundane article about bacteria on Mir & the ISS? It's hardly a discussion about the rightful sovereign of eastern Ukraine.
A better analogy would be if the Jamestown settlers had spent 10 years floating in the English Channel being resupplied by rowing boat rather than actually getting on with the business of crossing the ocean and settling somewhere. The whole programme is frankly a total waste of time and money which is a huge distraction to actually making any progress in manned space exploration.
I'm not saying you're wrong, but every announcement from NASA about the ISS seems to have the tone of "It may be in LEO, but it's an invaluable research platform teaching us lessons that are directly transferable to colonizing the Moon/Mars". Is that an unfair summary of what's happening on the ISS?
Yeah the ISS is where we're learning how to actually run a long term space habitat. Each station has taught us more about tons of things that happen here on Earth by removing the effects of gravity so that other forces with much smaller effects can be examined and harnessed. There are other ways we might have gotten this data but there's a lot to be said for having a person there to repair anything that's gone wrong or to change experimental apparatus instead of having to launch it all again.
"During the advisory council meeting, in response to questions, Gerstenmaier also made it clear that NASA didn’t require a vibrant commercial presence in low-Earth orbit as a staging point for missions deeper into space."
It also sidesteps the partners operating the ISS; NASA isn't the only one (albeit possibly the largest one) on the station.
> If nothing else, the ISS would be useful for "worker housing" during such assembly projects.
Interestingly Russia plans to take some of their part from the ISS to build another space station (https://en.wikipedia.org/wiki/Orbital_Piloted_Assembly_and_E...) that will exactly have this role of an intermediary "gas station" between earth and space exploration
ISS takes up about 15%-18% of NASA's budget. It's slated to cost NASA about $3 billion per year, at least, through the rest of its life.
Is that cheap, as far as hundred billion dollar space stations are concerned? Or is that expensive as far as moving on to new projects is concerned (and having budget drag from a legacy program that will be ~30 years old in 2024)? That's part of the debate. Personally I'd rather Congress give NASA another $3 billion in funding just to keep the ISS until we (hopefully) begin replacing it.
Just keeping the ISS in orbit would require at least one mission every year or so to boost it into a higher orbit and re-stock some of the consumables.
These missions cost something like half a billion each.
I think NASA should capture an asteroid and place it into a stable Lagrange point. The mass of the asteroid could provide resources, radiation shielding, and additional gravitational stability for other facilities/assets at the same Lagrange point.
If suitable engineering is done, stations could undock from the radiation shield and updated stations docked in place, so the investment in delta-v and materiel could be preserved.
Lagrange orbits aren't that great in the long run, and come with their own unique set of challenges (from en.wikipedia.org/wiki/Lagrangian_point#Mathematical_details):
"Although the L1, L2, and L3 points are nominally unstable, it turns out that it is possible to find (unstable) periodic orbits around these points, at least in the restricted three-body problem. These periodic orbits, referred to as "halo" orbits, do not exist in a full n-body dynamical system such as the Solar System. However, quasi-periodic (i.e. bounded but not precisely repeating) orbits following Lissajous-curve trajectories do exist in the n-body system. These quasi-periodic Lissajous orbits are what most of Lagrangian-point missions to date have used. Although they are not perfectly stable, a relatively modest effort at station keeping can allow a spacecraft to stay in a desired Lissajous orbit for an extended period of time. It also turns out that, at least in the case of Sun–Earth-L1 missions, it is actually preferable to place the spacecraft in a large-amplitude (100,000–200,000 km or 62,000–124,000 mi) Lissajous orbit, instead of having it sit at the Lagrangian point, because this keeps the spacecraft off the direct line between Sun and Earth, thereby reducing the impact of solar interference on Earth–spacecraft communications. Similarly, a large-amplitude Lissajous orbit around L2 can keep a probe out of Earth's shadow and therefore ensures a better illumination of its solar panels."
Earth-Moon L4 and L5 is still very unstable due to the Sun (and other planets).
Earth-Sun L4 and L5 is more stable, but almost useless as a waypoint; however there are already naturally captured asteroids (and a lot of dust) already there.
All orbits require station keeping in a dynamic solar system that is circling around a black hole.
If the asteroid has any water, station keeping won't require external fuel. If it doesn't, mass drivers could be used to toss chunks of the asteroid off and correct for instability (though that might create space debris if the velocity isn't enough).
By shielding, do you mean that astronauts could live inside or behind the asteroid, just using its mass between them and the sun? That would be pretty dark and cold. As far as I know, no asteroids have major magnetic fields.
I am totally with you on using the asteroids for materials, but I am not sure that they would provide useful gravity either. Even one of the largest near-earth asteroids, 433 Eros, only has a surface gravity of 0.0059 m/s^2. Is that useful?
By shielding, do you mean that astronauts could live inside or behind the asteroid, just using its mass between them and the sun?
I mean that the habitable modules would be located inside silos embedded within the asteroid, so that the living space would be entirely surrounded by radiation shielding mass.
That would be pretty dark and cold.
The problem in space is generally getting rid of heat. Vacuum is a great insulator, insulation material is effective and relatively cheap, and radiative cooling is fairly slow. The other thermal problem is exposure to direct sunlight. The asteroid as a shell of massive shielding would help in this regard.
The largest thing NASA has moved above low earth orbit since the early '70s is, what, Galileo? How many orders of magnitude are there between G and your asteroid?
Cassini was launched in 1997 and weighed over two and a half times what Galileo did (5712kg vs 2223kg). Still several orders of magnitude less than an asteroid.
Not yet, but perhaps in the near future. The National Space Society has a proposal up for capturing 99942 Apophis via gravitational slingshot, which would be fairly damaging if we managed to crash it.
Lets put it this way. The largest asteroid in the inner Solar system, Ceres has a mass of 1.3% of the moon.
The size of asteroid we are talking about here is likely to be closer to a container ship or maybe a small hill. Perhaps 1 millionth of the size/mass of Ceres at the most.
Why not halfway between us and the moon? It could be an easy-to-reach halfway point for the Moon, a refueling station and very-low-g launchpad other points, internet relay base, and also have commercial, industrial, and housing areas.
This could be an interesting new step in human modification of the environment - "orbitforming" (like terraforming?) a better solar system. It's like razing a hill to make way for farmland or better city building conditions.
An asteroid that's easy for vacationing billionaires, mining companies, and highly-pollutant industry to reach would be a great next step for humankind.
LEO is an orbit around Earth with an altitude between 160 kilometers (99 mi), and 2,000 kilometers (1,200 mi) The moon is on average 384,400 kilometers (238,900 miles) away. The Moon(ish) is where NASA is headed, LEO is what they're leaving behind.
Well, that was a big chunk of ice (comet core) and they stuck a bare fission reactor core in it to make a steam rocket. And they had robot swarms to mine/shape ice. It's a very cool book, though!
I don't know what the grandparent's point was, but I believe that kinetic weapons are exempt from space weapons treaties, hence the "Rods from God" satellite designs.
There are many reasons, but one key reason is solar radiation. The current orbit of the ISS means that is mostly protected from harmful radiation by Earth's magnetic field. If you moved it away from Earth, you would not have that protection and the station would become very dangerous.
Another reason is resupply. The station can only run for a few months or a year without resupply, and the further you move it away the more difficult and expensive resupply becomes.
There are a host of other reasons, but they all stem from the fact that the ISS was engineered to always be close to Earth, and the space environment elsewhere is sufficiently different that the ISS basically can't work in a dramatically different orbit.
Thanks - those make sense. I wonder if there is any opportunity to keep it in use or relevant. We spent $140 billion putting it up there, so if its not viable to spend 2% of that per year keeping it going then I understand the need to deorbit.
Yeah, we can keep B-52s flying for 50 years with insane numbers of launch-land cycles, I'm pretty sure the ISS can fly for a very long time. SpaceX can already resupply it. I don't see why they wouldn't take it over.
B52s can be completely disassembled in a shirt sleeves environment and we've barely explored on orbit construction. The ISS can't be stripped down so far which is actually causing an issue with bacterial growth in places that can be reached on orbit to be cleaned. At a certain point things that are hard/impossible to reach will reach the end of their lifespan and the inhabitants are in too much danger.
How about moving it further up, but making the station completely unmanned, run by robots. They don't even have to be autonomuous, due to the low distance they can be remote-controlled -- fewer resources needed to keep in orbit, fewer resources needed because there aren't any humans. Plus the main inhabitants don't have issues with the vacuum of space, so many experiments could be parked 'outside', maybe on those lattice structures.
Used where and for what? The international space station was originally intended as a low earth orbit base for human space activity, then gradually morphed into a low-gravity laboratory.
The space station can't hold itself together on the moon, it is not built for 1/6g; you might be able to position it in lunar orbit, but that would be quite expensive; higher orbits would preserve the station just as well at much lower cost, but the station would be an unsafe derelict in a few years.
Would it really be all that expensive though. We are going to have to send tons of mass out there eventually. Is there anything fundamentally different about a lunar orbit that would make such a base not as useful. I understand it was not designed to experience large acceleration forces but could we not use this as an opportunity to test ion drives and/or other low impulse drive mechanism? Slowly inch it towards a linear orbit? Then send astronauts to meet it in orbit with a next gen reusable lunar lander? On a SpaceX heavy and or SLS?
Nice idea. But, just to play with the numbers, it would require tons of fuel and, unless ura thinks of a debris field instead of a park, we must break and descent it there.
I suppose that whould cost a lot more than 140 billions.
"'We’re going to get out of ISS as quickly as we can,' said William Gerstenmaier, NASA’s chief of human spaceflight, last week."
If NASA gets out of ISS, it will not longer have a manned spaceflight program. It's not going anywhere without a launch vehicle, which it doesn't currently have.
We need to move on from NASA anyway. As a government organization it is always going to be somewhat capricious and compromised by the needs of politics (eg: part of the reason the Space Shuttle was so expensive is that it was spread out all over the country so each politician could claim jobs from it.)
NASA needs to get out of the way, and congress needs to get out of the way. Yes, some civilians will die in private spacecraft, but that doesn't mean that space tourism is not a valid thing. Civilians have died on cruise ships!
We need sub orbit, then orbit, then hotels, then a base from which trips to the moon can be considered. When all of this is an economically viable industry, then the civilization can consider the possibility of visiting another planet and not having all of our eggheads in one gravity well.
Government will not get us there, and at this point, given the hurdles put in front of Virgin Galactic, they are a hinderance-- at least part of the time.
> As a government organization it is always going to be somewhat capricious and compromised ...
That applies to every large organization. I've never heard of or worked in one that was otherwise.
Contrary to the conservative myth, the U.S. government's large organizations have a pretty good track record of innovation and getting things done. Consider the U.S. military, NASA (did you see those photos of Pluto?), most science funding, my highways are safe and very functional, my water and food supply are clean, prisons effectively hold prisoners, dams don't burst, my lights turn on, etc.
Of course they are very imperfect, like all large organizations, and constant vigilence and improvement is necessary. But I reject the idea that government is somehow innately incompetent and private business is innately superior. It's almost a rejection of the idea that democratic self-government can be effective. Really they are different tools for different jobs.
I don't agree with the GP view that the government does not have a role in the future of space. However as an employee in the government sector I can confirm that the stereotype of an inefficient organization is true. It's more then just being a large organization there is a real lack of competitive pressures that force efficiency. It's not a rejection of the idea that democratic self government is a good form of government it's just a recognition that there are certain downsides of the current implementations of government agencies.
> However as an employee in the government sector I can confirm ...
One person's anecdotal experience doesn't confirm anything. There are probably tens of millions of government employees in the United States alone.
> It's more then just being a large organization there is a real lack of competitive pressures that force efficiency.
That's true in many large organizations. Inefficiencies due to employees' (including managers') lack of exposure with any marketplace consequence are a very common, well-studied problem. See: Dilbert.
The space shuttle was about half as efficient as the Saturn it replaced. And that's only if you count low earth orbit. If you count beyond that, it is infinitely more efficient since the space shuttle couldn't go further.
The Saturn was given to us by basically empowering a dictator to run the program and get things done, a lot like a CEO. The Space Shuttle was given to us by typical bureaucracy, and lies. Lots and lots of lies told with a straight face to the public.
I don't know that private companies can ever compete with NASA on the scale of spending, but given NASA's current relatively tiny budget, it doesn't seem out of the question.
And I like to daydream about a future where the space shuttle never happened and the Saturn XX single stage super rocket takes vacationers to the moon and then lands itself on its landing pad ready for a quick refuel and return trip.
> The Space Shuttle was given to us by typical bureaucracy, and lies.
You forgot the military. They're e.g. the reason it has such big wings, because they wanted a huge single-orbit crossrange capability. Presumably for spying, maybe as a backup in case the Russians shot down a Keyhole or something.
I'd disagree on politics making the space shuttle more expensive - the shuttle would have cost about the same no matter where the factories went to built it - it was a deeply flawed concept from the start, and one borne largely out of politics.
It's really not you had parts built all over due to politics each with a different quality control process which lead to issues of major parts not fitting properly because they were manufactured to slightly different tolerances, about 40% of the tiles have had to be rejects due to this for example, major engine components also have had this issues.
Also due to politics the shuttles have had to be assembled in California and then flown to Florida which was very expensive process.
Government projects are tend to be designed as too big to fail and bring as much work to as many states as possible because that what gets you the vote.
This isn't an argument against NASA, NASA is very much needed there are a few fields you do not want to hand off to the private industry completely (and ideally not at all) and space exploration is one of them.
SpaceX is for the time being more or less a unicorn because it is privately held and for the time being Elon Musk does not have to answer on every decision to shareholders when it will come to that the overall level of innovation will slow down, commercial space flight isn't a bad idea but commercial altruistic space exploration is a pipe dream in the long run.
You will not find many companies that will be willing to take on a 20-30 years Mars project for nothing than their own fame, yes working for NASA on such projects is very lucrative but in the absence of NASA it just wont work because there will be very little financial drive to do so. ULA/LM doesn't want to go to Mars they want NASA to choose Orion and their launcher to go to Mars and pay them heavily to develop and build it even if it never gets used.
When you have different manufacturing facilities you will always have this issues even when you are building to the same spec.
Your manufacturing process will have different tolerance biases that's unavoidable.
The problem happens when you stack tolerances in an additive manner for example when you have a nut which is built to spec in plant one and is 0.005% too big (which is well within the tolerance limit) and you have the bolts built in plant 2 and they come out 0.005% too small (which on their own is still within the spec) you get an overall tolerance shift of 0.01% which all of a sudden is out of spec.
This just happens in manufacturing all the time the parts are in spec individually but the end result just doesn't work.
I actually deal with this all the time in hobby electronics you buy various parts which all of them have a spec with +- certain percent and you when you buy them from a single batch you can be quite out of luck and find out that when you add them all together the tolerances just stack against your initial design.
Speaking as an engineer, you're supposed to design for the worst-case tolerance stack to be viable...
If 0.01% is out of spec then you need tighter tolerance specs on your individual components or otherwise your design does not mathematically make sense.
This sounds like a design and process control issue as much as anything.
It is a process control issue, the problem is that controlling the process when you have 100 of sub contractors manufacturing parts which are pre-assembled in 10 different locations and then sent for final assembly isn't that easy. And even if you add tighter tolerances to the spec you can still end up with things not working properly.
Not to mention that increased tolerances means higher costs and there's a point where you can't adhere to them physically and as far as real world manufacturing goes the tighter your tolerances are the tighter the control and QA needs to be which results only in diminishing returns.
When you end up manufacturing things tolerances can be skewed by a 100 different reasons from a slightly different zero and certification process to different CAD/CNC software which rounds up thing slightly differently.
The ISS development actually learned quite a few things with that and they've both adjusted their process segmented the manufacturing by entire modules rather than individual parts then the only thing you need to really worry about are the tolerances for the actual dock which have quite a bit of wiggle room.
If you had to make the frame for the cupola in Italy, the outer housing in France the Windows in Germany, the Shutters in the Netherlands and assemble them in the UK you would ended up with similar problems.
Saying there's nothing wrong with X you just need a better process can be said for pretty much everything but that argument rarely holds water when you deal with real world applications, there's a reason why there are entire engineering disciplines for manufacturing and process control.
So no as an Engineer you need to design tolerances not for the worse case scenario but for the actual manufacturing process you are using and the controls you can enact on that process.
When that process is then spread out across as many parties as possible it's no longer the process you've started with and quite likely isn't neither and ideal process nor one you could ever really optimize.
There's a good reason why some of the worlds most advanced engineering parts are still quite often hand fitted at the end, and that's when you work with a single manufacturing process in a single factory.
When you spread that out you end up with parts that sometimes can't even be hand fitted anymore.
And the reason it was a deeply flawed concept was...politics. The Shuttle that the politicians would allow NASA to build was not the Shuttle that the NASA engineers originally wanted to build.
Imagine if the people who founded Jamestown said, "hey, we're ready to start moving deeper in the continent, so let's burn Jamestown and push it into the ocean first." Why give up a beach head?
Our reach on single missions is constrained by our rocket size. Therefore to do bigger missions, we will need to assemble and supply spacecraft in space over multiple launches, as we have assembled the ISS. If nothing else, the ISS would be useful for "worker housing" during such assembly projects.