NASA pushes back timing of ISS deorbit vehicle contract NASA has tweaked the contract and shuffled the dates for its procurement notice covering a vehicle to deorbit the International Space Station (ISS.) While the agency should probably have carefully considered and planned how disposal would happen more than a quarter of a century ago, when construction began, NASA only put out a …
That's hoping that it won't be late which, given Humanity's track record on getting space right the first time, is far from guaranteed.
But one thing is certain : the ISS will be coming down. The challenge is making that happen in a controlled manner. Right now, that challenge is on the funding. We'll see how Round 1 goes down. That'll give insight on how Round 2, getting ready to de-orbit, might pan out.
> the ISS will be coming down
It could be boosted using existing ion tug technology but the bigger problem isn't its orbit
It's suffering the same space fungus problem that MIR had, meaning that reusing segments of it (as has been repeatedly proposed) may potentially cause that fungus problem to develop faster on newly attached modules
Rather than 'safely de-orbit', which is a polite euphemism for crash into the earth with a degree of probability for where it will hit, why not push the orbit further out to a point where it has an acceptably low probability of coming back?
Yes, I know this is rocket science but boosting to a higher orbit is a fairly well studied area so maybe?
It would take a lot more energy to get it to that higher orbit than to re-enter, it would put a large amount of mass into a position where a single impact would generate debris over a huge orbital range* and, with a controlled re-entry, it's reasonably easy to ensure that anything large enough to reach the ground goes into the ocean; the issues come when effective control is lost.
*in a low orbit, almost all impacts result in at least half the debris re-entering faster than on an undisturbed orbit while, in a graveyard orbit, that could potentially mess up the extremely valuable GEO patch and put debris deep down into low orbit with a much higher velocity. In both cases, re-circularising at lower/higher orbits than the impact altitude is impossible from a single impact but they cross over more readily. With the ISS where it is, debris from an impact will still always suffer from some appreciable drag and, with smaller particles, the drag/mass ratio becomes much higher than the original station.
"Rather than 'safely de-orbit', which is a polite euphemism for crash into the earth with a degree of probability for where it will hit, why not push the orbit further out to a point where it has an acceptably low probability of coming back?"
There's a spot in the ocean designated as a place to splash spacecraft. It's away from shipping lanes, fisheries and not even private yachts go there. There is the technology and math to hit that spot with a good degree of accuracy, not just a "maybe if we're lucky".
Boosting it to a higher orbit is a short term solution and it would remain a problem for decades or even hundreds of years afterwards with little chance of reversing that decision in the future. I expect it would be easiest to delete modules rather than the whole thing in one go.
From my naive perspective it does appear simpler to disassemble the thing and deorbit those smaller sections, separately, rather than the entire thing all in one go. Easier to calculate the deorbit trajectory for a simpler shape. Not that disassembly would be simple.
Perhaps "simple" is the wrong term. "More controllable"...?
It's possible that parts may have ultimately locked/seized, or even cold-welded together. Ultimately it might have been considered a benefit if two mated parts welded together back when assembly and making it airtight were the big concerns.
Plus it took a lot of manhours and flight time with a fair amount of risk to assemble it, and the craft that facilitated that process is now gone. Disassembly could be a bit of a nightmare, and every nut and bolt that slips out of the astronauts' hands is another space hazard.
""...set the controls for the heart of the sun"?"
Going inward towards the sun is actually more energy intensive. It wouldn't be a problem to miss Venus and Mercury, but sending valuable metals to burn up in the sun is a waste. I'm not sure how deep the ocean spacecraft graveyard is, but it's going to be mineable for some amount of money should it be needed.
4000m, roughly.
There's also not that much there, the largest pieces are generally under 1m across and maybe 200kg after impact.
(IIRC, the biggest bit of Skylab that hit Australia was much larger, but exploded on impact)
So absolutely big enough to really ruin your day on the way down, but too small to be worth trying to recover from the deep.
While the agency should probably have carefully considered and planned how disposal would happen more than a quarter of a century ago, when construction began, NASA only put out a request for proposals for a deorbit vehicle in September 2023.
Would you rather order a 16GB memory module in 1998 or 2023?
It is still early for a complete plan to de-orbit ISS. Several new launch vehicles are being developed with at least two likely to be functional next year.
The EMP alone would cover basically everything inside the Van Allen belts. The intense heat pulse would probably disrupt or destroy outright anything within a hundred kilometers or so with stuff further away affected by radiation, heat and possibly a shockwave (doesn't take much material to form a shockwave in a vacuum and it doesn't take much to destroy a craft designed to "float" at 0g in a vacuum.)
Would it vapourise it? Or would it vapourise some of it, melt some of it, fragment whatever's not been vapourised and push it all in random directions at very high speed? Never mind the effects on other stuff in LEO... the EMP could fry a lot of nearby stuff. I don't know if there'd be a blast wave in space, intuition says not, but all the energy from the blast has to go somewhere and that somewhere is the immediate vicinity.
The ISS is only 110m long. I don;t think you need much of a nuke to vapourize everything within 55m. This picture shows some rebar surviving at one of the Trinity test foundations, 100 feet from The Bomb, but perhaps the ground shielded it.
Anyway, maybe it's time we tried it, if only for the shits and giggles.
"This picture shows some rebar surviving at one of the Trinity test foundations, 100 feet from The Bomb, but perhaps the ground shielded it."
I've visited there and have photos of the rebar. I thought the site had been excavated in the blast, but they explain how the boundary effect works to prevent that to some extent. A big enough bomb will make a crater.
Nothing (other than the bomb core) got disassembled at Trinity, merely disassembled rapidly. Most of the tower was collected a few years later with only some fragments unaccounted for
There are a bunch of followup experiments on how close things needed to be to be melted or vaporised and the answer turned out to be "Extremely close indeed"
It was this discovery and subsequent tests at Bikini atoll with carbon coated steel balls (which were found a couple of miles away, missing a fraction of a millimetre of their coating) which convinced Freeman Dyson that Stanislaw Ulam's crazy Project Orion proposal would work
https://newatlas.com/orion-project-atom-bomb-spaceship/49454/
The Register 
Biting the hand that feeds IT
Copyright. All rights reserved © 1998–2025
