Letting the ISS burn up......Why?

[Nibb31]

3 hours ago, sevenperforce said:

Do we know this for sure?

As far as I know, we have never filmed the reentry of a craft not meant to survive reentry from inside the craft. There is actually quite a bit of good information we could glean. Which modules survive the longest? Do lightweight craft self-stabilize, or do they tumble wildly? How far can the hull breach before it triggers catastrophic unplanned disassembly? Is there just one failure mode, or are there several, possibly complementary ones?

And what would be the purpose of spending millions of dollars to answer those questions? Once a spacecraft is deorbiting it's finished. It's not like there is any purpose in improving the survivability of reentering space station modules.

I'd rather spend that money on developing new technology.

 

Edited April 2, 2016 by Nibb31

[fredinno]

40 minutes ago, Nibb31 said:

And what would be the purpose of spending millions of dollars to answer those questions? Once a spacecraft is deorbiting it's finished. It's not like there is any purpose in improving the survivability of reentering space station modules.

I'd rather spend that money on developing new technology.

 

Millions are not that much in terms of space. I doubt it would cost more than 5 million, TBH, and that's fairly cheap.

[Nibb31]

11 minutes ago, fredinno said:

Millions are not that much in terms of space. I doubt it would cost more than 5 million, TBH, and that's fairly cheap.

Still a waste of money.

[RocketSquid]

6 hours ago, Nibb31 said:

Still a waste of money.

Most of the manned missions so far have been a "waste of money" by that standard. There are exactly two reasons to bring humans into space: Figuring out what living in space does to humans, and PR. The first is useful because sooner or later, we're going to need to start living in space. The second is useful because it helps secure funding for space programs. If NASA wants to make a heat-hardened camera to film the ISS as it reenters, it will cost money ("funds"). But if they release the footage, it will teach us a bit about reentry and how an unshielded object decays, but more importantly, it will create publicity ("reputation"). This in turn will likely help NASA become more popular, which means congress will be more likely to give them a larger budget. It's like a contract in KSP. You have to spend some funds to complete it, but you get funds, rep, and science out of it.

Meanwhile, if we keep the ISS in orbit, we would have to maintain it. This only becomes useful if someone can: a) profit from it remaining there, perhaps if space tourism becomes a bigger bushiness is could be the ultimate space museum/ historical reenactment; or b) find a different reason to keep it there (budget space hotel?).

A more practical option would probably be to take it apart. That thing has habitation space, heavy trusses and large solar panels and radiators, all of which are necessary for space stations, and it would likely be cheaper to move them than to launch new ones.

Also, just a note. According to wikipedia, the ISS had cost $150 billion dollars to construct as of 2010.

[Nibb31]

3 hours ago, RocketSquid said:

Most of the manned missions so far have been a "waste of money" by that standard. There are exactly two reasons to bring humans into space: Figuring out what living in space does to humans, and PR.

PR has never been the main reason for sending people to space. It might have been a corollary, or it might have been a side-effect of demonstrating soft-power.

 

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The first is useful because sooner or later, we're going to need to start living in space. The second is useful because it helps secure funding for space programs. If NASA wants to make a heat-hardened camera to film the ISS as it reenters, it will cost money ("funds"). But if they release the footage, it will teach us a bit about reentry and how an unshielded object decays,

We already know a lot about reentry, and there really isn't much point in learning how a decaying object breaks up because it's going to break up anyway. We already know how stuff burns up. What do you think the applications of such knowledge would be? Designing future space stations so that they burn up prettily ?

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but more importantly, it will create publicity ("reputation"). This in turn will likely help NASA become more popular, which means congress will be more likely to give them a larger budget.

How exactly does a video of a space station burning up convince congress to give NASA more money ?

If anything, the reactions from the general public will be akin to this thread: NASA is wasting taxpayer money by letting it burn up.

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It's like a contract in KSP. You have to spend some funds to complete it, but you get funds, rep, and science out of it.

No. Real life is very little like KSP. Funds are not proportional to reputation and science isn't counted in points.

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A more practical option would probably be to take it apart. That thing has habitation space, heavy trusses and large solar panels and radiators, all of which are necessary for space stations, and it would likely be cheaper to move them than to launch new ones.

No it wouldn't. You can't disassemble the ISS. Disassembly is the reverse of assembly. It would require just as much work to disassemble it as it took to assemble it, including a lot of EVAs, training and writing procedures, studies, etc...

If the ISS is decommissioned, it's precisely because the solar panels will no longer be producing power, the radiators will be all leaky and the habirable volume will be obsolete. 

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Also, just a note. According to wikipedia, the ISS had cost $150 billion dollars to construct as of 2010.

And it would cost a large portion of that to deconstruct it.

Edited April 2, 2016 by Nibb31

[fredinno]

8 minutes ago, Nibb31 said:

We already know a lot about reentry, and there really isn't much point in learning how a decaying object breaks up because it's going to break up anyway. We already know how stuff burns up. What do you think the applications of such knowledge would be? Designing future space stations so that they burn up prettily ?

How something that big will fare on reentry? The only things comparable to the ISS in size that we have good information on reentry is pretty much the Space Shuttle. If we figure out how different materials heat up during atmospheric reentry, that may allow us to aerobrake probes faster, with more confidence on the safety on how those things burn up- or what happens when a large heat shield is punctured. BTW, 5 Million is the cost of 7 Cubesats.

9 minutes ago, Nibb31 said:

If anything, the reactions from the general public will be akin to this thread: NASA is wasting taxpayer money by letting it burn up.

The Skylab burn up on reentry was a pretty big public event :https://en.wikipedia.org/wiki/Skylab

[Motokid600]

I never looked at it in the sense that  good video of the station burning up could be bad PR. And now that I think about Nibb is right on that. The common man is indeed a fool. More so now a days then ever. I guarantee you when the stations time comes it'll be this big story and people will immediately jump to conclusions. "Oh my god the space station is falling out of the sky Nasa is the biggest waste of money ever." .... Despite it having been talked about and planned for eight years. 

 

Not sure on that one. I won't lie I only want video simply because it'd be neat to see. That's not worth 5 million though. Nor is it worth the cries of the ignorant populace. We'll get video... There's no doubt about that. Maybe not from onboard, but from drones and planes no doubt.

[fredinno]

6 hours ago, Motokid600 said:

I never looked at it in the sense that  good video of the station burning up could be bad PR. And now that I think about Nibb is right on that. The common man is indeed a fool. More so now a days then ever. I guarantee you when the stations time comes it'll be this big story and people will immediately jump to conclusions. "Oh my god the space station is falling out of the sky Nasa is the biggest waste of money ever." .... Despite it having been talked about and planned for eight years. 

 

Not sure on that one. I won't lie I only want video simply because it'd be neat to see. That's not worth 5 million though. Nor is it worth the cries of the ignorant populace. We'll get video... There's no doubt about that. Maybe not from onboard, but from drones and planes no doubt.

It's more about the science than the video.

[Rath]

Grab a chunk, boost it to an higher orbit.  Compromise.  

 

I hope we put something big up there again.though.  

 

But the ISS was built to keep the soviet scientists occupied so they wouldn't go build missiles, and much of the science that can be done with <1yr human flights is done.

[todofwar]

Even if it is rather old tech at this point I still think it might be useful to try and repurpose some of the parts for either an interplanetary ship or maybe even a moon base. We're talking tons of material already in orbit, and the most expensive part of space is getting things into orbit. Sure, they would take extensive retrofitting, but you could conceivably launch an inflatable workstation up there just big enough to accommodate one unit at a time, and retrofit/gut each piece individually. Even if only the structural shells can be saved it could easily be worth it. 

[fredinno]

18 hours ago, Rath said:

Grab a chunk, boost it to an higher orbit.  Compromise.  

And the point of that would be...?

18 hours ago, Rath said:

But the ISS was built to keep the soviet scientists occupied so they wouldn't go build missiles, and much of the science that can be done with <1yr human flights is done.

Source?

From what I've read, it has more to do with actually making the work on Mir-2 and Space Station Freedom finally be fruitful, and to give the Shuttle work to do (it was intended to launch to 2030 until Columbia happened.)

And I doubt that much of the science that can be done has been done. Seriously, look at the number of Antarctica research stations. https://en.wikipedia.org/wiki/Research_stations_in_Antarctica

Add artificial G experiments, and you now have a huge amount of stuff to study. Your argument is similar to saying that there is no science to be obtained on Mars or the Moon because we've gotten so much. IRL is not KSP. Answering questions lead to more questions.

5 hours ago, todofwar said:

Even if it is rather old tech at this point I still think it might be useful to try and repurpose some of the parts for either an interplanetary ship or maybe even a moon base. We're talking tons of material already in orbit, and the most expensive part of space is getting things into orbit. Sure, they would take extensive retrofitting, but you could conceivably launch an inflatable workstation up there just big enough to accommodate one unit at a time, and retrofit/gut each piece individually. Even if only the structural shells can be saved it could easily be worth it. 

No it isn't. The expensive part of space is building the satellites.

https://en.wikipedia.org/wiki/Mars_Reconnaissance_Orbiter ($720 Million cost)

https://en.wikipedia.org/wiki/Atlas_V#Cost (LV for MRO: $164 Million cost)

Also, the ISS was not meant to be taken apart. Doing so means making deals with all the other nations involved, since international modules are attached to US modules, and you often can't get rid of one without going the same to another.

[Rath]

Ok, much of the science that can be done with the stuff on the station has been done.

And the group of crotchety old millionaires called congress doesn't want to spend more money.

[fredinno]

35 minutes ago, Rath said:

Ok, much of the science that can be done with the stuff on the station has been done.

And the group of crotchety old millionaires called congress doesn't want to spend more money.

How do you know? Seriously, go back, and look at the Antarctic research stations. There is plenty of science available in Space, and as I said earlier, answering one question in Science usually leads to even more questions. The problem is not lack of science.

[James Kerman]

Let it burn up on re-entry.  Since the Apollo missions humanity has been stuck in orbit.  If the ISS is gone then there is more chance and more funding to send humans further than the moon.

[John JACK]

On 02.04.2016 at 9:20 PM, Nibb31 said:

PR has never been the main reason for sending people to space.

Wasn't it? PR was the main reason to send people (and stuff in general) to space since always. That's the best show of "we CAN do it (and you do not)(so give us moneys)". First Sputnik was just dummy payload for new ICBM that had problems with reentry — hey, satellites do not need to reentry, let's just launch a satellite to show superiors some progress! Public effect of Sputnik was unpredicted, and next Sputniks were cobbled together in much hurry, mostly to keep a show running. USA spend even more money just to get human to the Moon and bring back some rocks, without much hope for profit or even science — mostly to show that we have that money and you do not.

Turned off space stations actually are not dead, they can be revived and used again. Salyut-7 suffered an unplanned power failure and was offline for several months, than rendezvoused, docked, fixed, heated, and working again. With planned conservation stations can be mothballed at least for several years, at high enought orbit. Big composite stations like Mir and ISS may have more problems with structural integrity, but spaceworthiness and internal components should survive and remain serviceable. And "sails" are stowable to reduce drag and degradation — several big solar panels on ISS already are permanently folded to allow for docking new modules.

Reentry, when it comes to it, absolutely must be controlled. Even of mentioned Salyut some pretty heavy parts reached surface intact. Luckyly, there are not many houses near Pacific parking orbit. And reentry camera footage must be not too expensive and very cool. Expensive space station is falling out of space and burning up anyway, why not film it? People just love watch expensive explosions.

[Nibb31]

7 minutes ago, John JACK said:

Wasn't it? PR was the main reason to send people (and stuff in general) to space since always.

You're confusing PR and propaganda/soft power.

Either way, a spending millions to rig GoPro cameras to a dead ISS just to post a YouTube video does nothing to for either PR, propaganda or science. It's pointless, not "cool".

 

7 minutes ago, John JACK said:

Turned off space stations actually are not dead, they can be revived and used again. Salyut-7 suffered an unplanned power failure and was offline for several months, than rendezvoused, docked, fixed, heated, and working again. With planned conservation stations can be mothballed at least for several years, at high enought orbit. Big composite stations like Mir and ISS may have more problems with structural integrity, but spaceworthiness and internal components should survive and remain serviceable. And "sails" are stowable to reduce drag and degradation — several big solar panels on ISS already are permanently folded to allow for docking new modules.

Not when the reason it's turned off is because it's reached the end of its shelf life. Once that happens, it just becomes a hazard. The solar arrays are not stowable (the folding mechanism was designed to unfold, not fold back) but even if they were, they will have degraded to the point where they will no longer be useful. Many parts are not designed to be serviceable, and many of those that are require an EVA and special equipment to do so. EVAs are expensive and require specific procedures and training.

I understand how emotionally attached we can be to our grandparents, but when a family member passes, we dispose of them through cremation or burial, because it's just not healthy to keep them around. Keeping a dead station loitering in LEO is just a hazard.

7 minutes ago, John JACK said:

Reentry, when it comes to it, absolutely must be controlled. Even of mentioned Salyut some pretty heavy parts reached surface intact. Luckyly, there are not many houses near Pacific parking orbit. And reentry camera footage must be not too expensive and very cool. Expensive space station is falling out of space and burning up anyway, why not film it? People just love watch expensive explosions.

You'll get plenty of nice footage from telescopes. NASA is not in the entertainment business.

[John JACK]

10 minutes ago, Nibb31 said:

NASA is not in the entertainment business.

Actually it is. NASA shows pretty much most of the interesting things going on. It may not be a direct PR of NASA, but it surely is a propaganda of science. And more public attention to science means more money to spaceflight. No one insists that NASA should launch missions just for fun (although space tourists), but salvaging great and unique footage is not that costly and gives more profit than not salvaging anything. Watching SPACE STATION BURN!!! up close worth incomparably more than blurry video of some fireball. And retrieving footage is not impossible, there are different sample return capsules, that can be rigged to separate after reentry.

17 minutes ago, Nibb31 said:

Not when the reason it's turned off is because it's reached the end of its shelf life.

Shelf life is some arbitrary point when manufacturer does not want to give any guaranties, not when stuff stops working forever. Hundred years old canned goods are edible, fifty years old planes fly, thirty years old cars are sometimes better than new. Malfunctioned space station could be brought online again, conservated station surely would be.
Solar panels of Zarya module are folded right now. Don't sure about main panels, but anything that was made surely can be broken.
And there at least one "family member" who is kept as a museum piece. Even producing some science by the way

I insist not that ISS must stay in orbit by any means possible. But it really should stay in orbit all the time it is useable, and at least until someone launch new stations. Even then it may be refurbished and rearranged to use some parts even longer. But conservation is an option too, not impossible one.

[Buster Charlie]

I feel documenting the reentry might be useful insofar comparing projected failure of parts vs real life. Not that we expect to survive reentry,  but how our material modeling stacks up to real life.

 

Kinda like how they model new aircraft performance in a computer, but they still load a real physical one with strain gauges and bend the wings and other strains to verify it. Except on the ISS, you can't do destructive testing,  until  you're ready to destroy it.

 

Why is this useful? Because if something lasts longer, or not as long. It gives us an extra data point to check our assumptions.

[Nibb31]

4 minutes ago, John JACK said:

Watching SPACE STATION BURN!!!

...is not worth the expense. Astronauts have better things to do.

If you want entertainment, ask Hollywood.

4 minutes ago, John JACK said:

Shelf life is some arbitrary point when manufacturer does not want to give any guaranties, not when stuff stops working forever. Hundred years old canned goods are edible, fifty years old planes fly, thirty years old cars are sometimes better than new. Malfunctioned space station could be brought online again, conservated station surely would be.

Luckily for astronauts, that is not how human-rated space missions work.

Hardware is certified for a specific set of requirements. When you exceed those requirements, bad stuff happens (see Challenger, or closer to us, CRS-7). You don't want to have a toxic leak, a major power failure, or a module depressurize with a crew on board.

 

[fredinno]

1 hour ago, John JACK said:

And there at least one "family member" who is kept as a museum piece. Even producing some science by the way

Hmm, the ISS HAB module? Skylab B? Almaz?

1 hour ago, Nibb31 said:

 

Hardware is certified for a specific set of requirements. When you exceed those requirements, bad stuff happens (see Challenger, or closer to us, CRS-7). You don't want to have a toxic leak, a major power failure, or a module depressurize with a crew on board.

Mir managed to stay afloat for longer than its service life. But either way, taking the Space station into the 2030s is definitely possible. Just when it becomes too expensive to maintain, and unsafe should we deorbit it.

10 hours ago, James Kerman said:

Let it burn up on re-entry.  Since the Apollo missions humanity has been stuck in orbit.  If the ISS is gone then there is more chance and more funding to send humans further than the moon.

I think the ISS should stay for as long as it is safe, besides, NASA funding is not really "if we get rid of something, it'll free money for something else". Congress makes things 90% more complex on the budget side.

[Nibb31]

2 hours ago, Buster Charlie said:

Why is this useful? Because if something lasts longer, or not as long. It gives us an extra data point to check our assumptions.

We don't do assumptions on how a vehicle survives when it's outside of its safety envelope. The whole point of vehicle design is to ensure that the vehicle remains safe and controllable.

Once it's on a deorbit trajectory, it's going to burn up whatever you do. Why would engineers waste precious time calculating reentry simulations for stuff that is destroyed?

 

[GDJ]

3 minutes ago, Nibb31 said:

We don't do assumptions on how a vehicle survives when it's outside of its safety envelope. The whole point of vehicle design is to ensure that the vehicle remains safe and controllable.

Once it's on a deorbit trajectory, it's going to burn up whatever you do. Why would engineers waste precious time calculating reentry simulations for stuff that is destroyed?

 

Well, the ISS is pretty darn big, and a good chunk of it is going to hit the Earth. It's good to do the simulations to know where and how much is going to land on Aunt Bessie's sunflower patch in the back 40, eh?

[sevenperforce]

9 minutes ago, Nibb31 said:

We don't do assumptions on how a vehicle survives when it's outside of its safety envelope. The whole point of vehicle design is to ensure that the vehicle remains safe and controllable.

Once it's on a deorbit trajectory, it's going to burn up whatever you do. Why would engineers waste precious time calculating reentry simulations for stuff that is destroyed?

Are you really suggesting that there's absolutely no way we could glean useful data from a better understanding of how modules intended for on-orbit endurance handle unprotected re-entry? After all, it's not like space flight ever involves unplanned emergencies.

Bare minimum, using a video feed from the deorbit of the ISS would provide useful data for determining how aggressively we could aerobrake an unprotected orbital module in an emergency situation.

But it's bigger than that. We can model a lot of stuff, but we also need to be able to test our simulations. Having real data from the breakup of multiple ISS modules would provide a huge resource for testing our modeling software. If our software gives predictions which diverge wildly from the actual sequence, then that's something worth knowing. We may never need to exactly predict the breakup altitude of something the exact size of the ISS again, but that doesn't mean we won't be simulating breakups for other purposes.

For example, what if ten years passes and we find ourselves with a need to controllably return sturdy payloads from orbit to Earth? Is it inconceivable that spent tanks or disposable modules, with their low mass and high surface area, might be used to "bleed off" the first few km/s of orbital speed, allowing the heat shield to be that much smaller?

There are so many reasons why this sort of data might be useful.

 

[fredinno]

14 minutes ago, sevenperforce said:

Are you really suggesting that there's absolutely no way we could glean useful data from a better understanding of how modules intended for on-orbit endurance handle unprotected re-entry? After all, it's not like space flight ever involves unplanned emergencies.

Bare minimum, using a video feed from the deorbit of the ISS would provide useful data for determining how aggressively we could aerobrake an unprotected orbital module in an emergency situation.

But it's bigger than that. We can model a lot of stuff, but we also need to be able to test our simulations. Having real data from the breakup of multiple ISS modules would provide a huge resource for testing our modeling software. If our software gives predictions which diverge wildly from the actual sequence, then that's something worth knowing. We may never need to exactly predict the breakup altitude of something the exact size of the ISS again, but that doesn't mean we won't be simulating breakups for other purposes.

For example, what if ten years passes and we find ourselves with a need to controllably return sturdy payloads from orbit to Earth? Is it inconceivable that spent tanks or disposable modules, with their low mass and high surface area, might be used to "bleed off" the first few km/s of orbital speed, allowing the heat shield to be that much smaller?

There are so many reasons why this sort of data might be useful.

 

Well, spent tanks for aerobraking sounds risky. You want to carry ballutes if you're planning to do that. But ballutes could probably benefit from ISS reentry data too to glean extra data to make them go deeper into the atmosphere.

[sevenperforce]

2 minutes ago, fredinno said:

Well, spent tanks for aerobraking sounds risky. You want to carry ballutes if you're planning to do that. But ballutes could probably benefit from ISS reentry data too to glean extra data to make them go deeper into the atmosphere.

Any sort of ablative or single-use or otherwise expendable re-entry system can benefit from the data that would be gleaned when the ISS burns up.