from the are-those-African-or-European-elephants? dept.
[...] Drift into the wrong part of the Pacific Ocean in eight years, and you might be in for a shock. Tearing through the sky will be some 400 tonnes (880,000lbs) of metal, set aglow by its re-entry through the atmosphere. This raging inferno will crash into the ocean, across an area maybe thousands of kilometres in length, signalling the end of one of humanity's greatest projects – the International Space Station (ISS).
The ISS has been orbiting the Earth since construction on it began in 1998. It has hosted more than 250 visitors from 20 countries since its first crew arrived in November 2000. "The space station has been a huge success," says Josef Aschbacher, the head of the European Space Agency (Esa), one of the more than a dozen partners in the programme. It has been a boon for international collaboration, not least between the US and Russia, who partnered shortly after the fall of the Soviet Union. "It is really one of the big international victories," says Thomas Zurbuchen, Nasa's former head of science.
But much of its hardware is decades old, which could eventually see the station become dangerous or even uncontrollable in orbit – a fate that befell the Soviet Union's Salyut 7 space station in 1985, requiring two cosmonauts to revive the tumbling station. "We really don't want to go through that again," says Cathy Lewis, a space historian from the National Air and Space Museum in the US.
To prevent such a catastrophe in space from happening once more, the space station will be deorbited in 2031, bringing it through the atmosphere to safely splash down in the Pacific Ocean. This will be the largest re-entry in history and, in March, Nasa asked Congress for funding to start development of a "space tug" that might be needed to perform the task – a spacecraft that can push the station back into the atmosphere. Kathy Leuders, head of Nasa's human spaceflight programme, later revealed it was estimated the tug vehicle would cost just shy of $1bn (£800m).
Working out how exactly to deorbit the station is a mammoth undertaking. Many large objects have burned up in the Earth's atmosphere, most notably Russia's Mir space station in 2001 and Nasa's Skylab space station in 1979. The ISS represents a whole new problem, however, being more than three times the size of Mir. "It is a significant challenge," says Jonathan McDowell, an astronomer at the Harvard–Smithsonian Center for Astrophysics in the US. "A 400-tonne object falling out of the sky is not great."
Beginning as the single Russian-built Zarya module in 1998, the station today is enormous, boasting 16 modules, vast solar panels mounted on a metallic truss, and radiators to expel heat. At 109m (356ft) in length it is the size of a football field, the largest human structure ever assembled in space. "It's like the pyramids of Giza," says Laura Forczyk, a space analyst at the US consulting firm Astralytical. A rotating crew of seven inhabit the station today.
[...] Events will begin in 2026, when the orbit of the ISS will be allowed to naturally decay under atmospheric drag, dropping from 400km (250 miles) to about 320km (200 miles) in mid-2030. At this point a final crew will be sent to the station, likely ensuring any remaining equipment or items of historical significance that have yet to be removed are done so, also reducing the weight of the station. "That is still in discussion," says Aschbacher.
Once the final crew has left, the station's altitude will drop further to 280km (175 miles), deemed the point of no return – where the station could no longer be boosted back above the drag caused by our planet's thickening atmosphere – a process that will take several months. Here, Russian Progress spacecraft are earmarked to then give the station a final push back into the planet's atmosphere.
[...] Whatever spacecraft is used, after this final push, the station will reach an altitude of 120km (75 miles), where it will hit the Earth's thicker atmosphere at some 29,000km/h (18,000 mph), beginning re-entry in earnest. First, the solar panels will be torn from the structure. "The headwind will be so much," says McDowell. Based on studies of the Mir re-entry, this might be expected to occur at an altitude of about 100km (62 miles) and take just minutes before they are all ripped away. Then at around 80km (50 miles) above the Earth's surface, the modules themselves start to be ripped apart from each other before they are set ablaze by the re-entry temperatures of thousands of degrees, causing them to melt and disintegrate. Several sonic booms will be heard as the wreckage streaks across the sky.
(Score: 1, Interesting) by Anonymous Coward on Sunday May 07, @12:36PM (1 child)
I wonder if Elon will bid on this job?
(Score: 2) by legont on Monday May 08, @06:07AM
Well, so far the only way to change ISS orbit is and ever was Soviet's Progress modules - the fact all articles like this try to mum. Progress takes cargo out there and uses fuel leftovers to steer the thing.
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 4, Funny) by Rosco P. Coltrane on Sunday May 07, @01:50PM (3 children)
200 elephants, 400 tons, 880,000lbs...
I'll tell you one comparison unit what would be very accurate and evoke the immense weight of this structure quite well: 1 ISS.
(Score: 2, Funny) by Anonymous Coward on Sunday May 07, @05:24PM (2 children)
But that doesn't evoke the visual of a meteor storm of 200 elephants raining down on us.
(Score: 2) by turgid on Sunday May 07, @09:13PM (1 child)
They'd be nicely barbecued by the time they hit the ground. Get the burger buns ready.
I refuse to engage in a battle of wits with an unarmed opponent [wikipedia.org].
(Score: 1, Funny) by Anonymous Coward on Sunday May 07, @10:18PM
How many football fields' worth of burger buns???
(Score: 1) by khallow on Monday May 08, @12:22AM
when I read:
Maybe they should see what SpaceX can offer? I don't think we'll see an order of magnitude drop in price for a one time project, but maybe a factor of four or five drop is reasonable.
(Score: 2, Insightful) by iconnor on Monday May 08, @01:55AM (4 children)
Please just push it farther out... leave it for future use if needed...
(Score: 3, Insightful) by corey on Monday May 08, @02:56AM (3 children)
I’m with you on that. When I read “400 tonnes of metal”, I thought, why can’t we reuse it? How much money and greenhouse gas emissions did it take to get all that up there?
Why can’t they rip out all the obsolete electronics and tow the shell over into a moon orbit for use there?
It’s insane to burn it all up.
(Score: 1, Interesting) by Anonymous Coward on Monday May 08, @03:12AM (2 children)
Anyone here know how to calculate the fuel required to move the ISS into lunar orbit? Seems likely that it's more than required to de-orbit it, but maybe not that much more??
(Score: 3, Insightful) by takyon on Monday May 08, @04:46AM
It would be a lot more. ISS is in low Earth orbit, which is nowhere near lunar orbit. The orbit is decaying constantly, so if you left it alone for decades it would crash land.
Pushing it into deep space with no plans to actively repair it would just serve to allow it to get destroyed by micrometeorites.
The good move would be to bring it down piece by piece with Starship. "Can't be done", supposedly? There's at least 8 more years to figure it out, more if it gets another boost in altitude.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 3, Interesting) by VLM on Monday May 08, @01:26PM
You've got a three parter.
The first part is the delta V for "anything" in low earth orbit to the moon is somewhat over 6 KM/s. Depends on how you define your altitudes for "orbit" and how long you're willing to wait for EXACTLY perfect alignment before leaving vs "Fuck it we'll burn an extra 50 m/s to leave today instead of next year".
The second part is remarkably hard to find stats of KG fuel vs delta V. The average reboost seems to boost the ISS about "a hundred" m/s so you'd need about sixty cargo rockets worth of fuel; not actually all that much, and a typical payload is "a thousand kilos of fuel" so back of the envelope time is "sixty thousand kilos of fuel". Of course that'll require a tank and so forth. Is Russian Progress ship fuel shelf stable long enough for lunar orbital injection? But, yeah, sounds like more than 50 thousand kilos and less than 100 thousand kilos
The third part is almost all equipment would have to be ripped out. The electrical system is designed for "most exactly ish" 45 minutes of darkness at a time, unsure if they'd be happy with that lunar orbit LOL. The cooling system is designed to pump against or radiate towards "room temp" ocean and would likely be VERY unhappy with rando moon temps ranging from pretty damn hot to pretty damn cold. Also see the thermal system which again was designed to radiate towards/against half the ISS facing the comfy-ish earth surface. Also see the commo system there is no TDRSS or similar equipment on the moon and all directional antennas would have to be relocated to the opposite side of the station (outward). Link budgets were likely never so high that it would work from the moon, maybe, but probably not, although I suppose its simpler/cheaper to put bigger antennas on the earths surface than on the ISS. You could replace pretty much everything except the structural trusses, but at that point send out a dedicated station to the moon. The biggest problem is some design choices are based on the idea that there's always a lifeboat that can land on the earth in a couple hours at worst, so requirements ranging from water supply to medical gear depend on worst case scenario you're on the surface of the earth in a couple hours at worst but from the moon it might be a couple days. Suddenly a burst appendix goes from "F it, just land and take care of it at an ER on the surface" to "you gonna do lunar surgery or die". Also this could be done but it'll probably be heavier so add an additional 10% mass and 10% required fuel.
(Score: 3, Interesting) by richtopia on Monday May 08, @02:25AM
It is a bit early, but I'm thinking I may have a Pacific vacation in 2031. If it is orbited at night and crosses someplace nice like Fiji, I would make a vacation out of the largest deorbit in history.