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Satellite Debris Forces ISS Crew Into Rescue Craft
Muad'Dave writes "CNN is reporting that the crew of the International Space Station was forced to take refuge from a possible collision of the ISS with a piece of space debris Thursday. From the article: 'Floating debris from a satellite forced the crew of the international space station to retreat to a safety capsule Thursday, according to a NASA news release. .. The debris was too close for the space station to move out of the way, so the station's three crew members were temporarily evacuated to a the station's Soyuz TMA-13 capsule, NASA said.'" Update: 03/12 18:42 GMT by T : The original story incorrectly said the ISS had 18 crew members. Luckily for the three in the Soyuz, that was a mistake.
Umm...since when does the ISS have 18 crew members? Last I'd heard it was 3 and going to be doubled to 6 in the next few months.
There are 3 individuals on board: 2 Americans and 1 Russian.
The current expedition is Expedition 18. See http://en.wikipedia.org/wiki/Expedition_18 . This likely got garbled at some point from something like "Expedition 18 Crew" to "18 crew."
Timothy strikes again!
One of our competitors trademarked the term "hypothesis". From now on, we will call them "boneheaded ideas".
If it hits the Soyuz, you just exit the module and seal the airlock. On the other hand, if you're on the far side of the station and it puts a hole in that much larger target, you're in a somewhat more precarious predicament.
Additionally, as the Soyuz is intended to return to earth, with all the stresses and such involved in that, it can probably withstand an impact better than the much less robust station.
Here's a picture of a PAM-D motor.
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
FTFA The space station is orbiting at 17,500mph. The debris is moving at 19,800mph. Assuming they are an precisely the same orbit, the debris is still moving at least 2,300mph relative to the station. (And worst case some 35,000mph...)
You might want to rethink trying to hit it with a golf club.
Harder than you'd think. To deorbit a fragment like this you need to:
So that's three major orbital manoeuvres, per fragment. And that sort of stuff is really expensive: in order to move from a circular orbit around the equator to a circular orbit around the pole, you need twice the delta-V that you used to get into orbit in the first place!
So it would probably be cheaper to use a single disposable vehicle that you launch to a specific debris cloud, and then it collects as much crap as it can and then deorbits. But even that's going to be a major project --- and much of the debris up there right now is on the order of paint flecks, which are damn hard to pick up (or even find).
So this sort of thing isn't nearly as simple as it first sounds...
So that's three major orbital manoeuvres, per fragment.
You make it too complicated. You don't have to pick up the fragment, move yourself, then drop the fragment. You just have to exchange velocity with the fragment during a very brief interaction, flinging you every-so-slightly outside your orbit,and flinging it every-so-slightly inside it's orbit. Gravity takes care of the rest.
much of the debris up there right now is on the order of paint flecks, which are damn hard to pick up (or even find).
Again, too complicated. What you need is something large, light weight, and sticky. A simple cylinder filled with an aero-gel just needs to fly through the debris cloud, letting the pieces impact the gel and get stuck there. The added mass, plus decreased speed, would automatically deorbit the collector.
http://www.mhall119.com
I believe the relative velocity was 2,300mph, not that it would matter much either way if it hit.
You make it too complicated. You don't have to pick up the fragment, move yourself, then drop the fragment. You just have to exchange velocity with the fragment during a very brief interaction, flinging you every-so-slightly outside your orbit,and flinging it every-so-slightly inside it's orbit. Gravity takes care of the rest.
Unfortunately all gravity is going to take care off is steering both objects around the earth in perfectly normal orbits. Remember, there's no such thing as an unstable orbit (excluding certain complicated interactions with other bodies) --- all orbits are stable unless they hit something (like the atmosphere). Any debris low enough to be easy to deorbit is most likely going to do so soon of its own accord anyway. To deorbit the rest, you're going to have to change its velocity by a lot. Otherwise you achieved nothing.
The only way of changing the velocity of such an object is either rapidly, which means a collision, or slowly, which means your vehicle's going to have to grab the target object and do an engine burn. A collision is going to produce secondary debris, and will most likely kill your vehicle. Grabbing the object is a horribly complex engineering problem.
Again, too complicated. What you need is something large, light weight, and sticky. A simple cylinder filled with an aero-gel just needs to fly through the debris cloud, letting the pieces impact the gel and get stuck there. The added mass, plus decreased speed, would automatically deorbit the collector.
No, not really --- if you're going slowly enough to let the particles stick, rather than just vaporise (causing secondary debris), you're not going to transfer enough momentum to do anything useful. Attaching your aerogel to a vehicle which you can use to deorbit the whole lot might be potentially useful, though, but you'll still need a hell of a lot of it. Debris clouds are huge. China's 2007 antisatellite test filled everything on a particular orbital plane from about 200km up to about 4000km up.
What's more, aerogel's only good against stuff small enough and light enough to capture --- that debris cloud contains an estimated 35,000 objects bigger than 1cm. These are likely to punch straight through your aerogel, causing yet more secondary debris...
You mean some sort of Inter-Agency Space Debris Coordination Committee? They could meet every year to discuss topics and hand out assignments for the next year, and they could make reports to the UN, and stuff. Trouble is, no one else would ever know they existed.
Yeah, for a 2002 model it's doing pretty good isn't it? (If you disregard the multiple times it has suffered systems failure on re-entry.)
Seriously - though people refer to the craft as generically as 'Soyuz', that is like referring to all Ford Thunderbird's as a 'Thunderbird' without regards to model year. The current mark of Soyuz is the Soyuz-TMA, which had it's first flight in 2002 and has only flown 12 complete missions with the 13th currently on orbit. It's had significant failures on three of those missions - including two of the last three.
The Soyuz has evolved significantly along its journey from a free flying general purpose orbiter to a dedicated station taxi. The internals of a current mark Soyuz bear little resemblance to the original.