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Discovery-Alpha dodge astronaut's space junk.
March 14, 2001 12:43 PM   Subscribe

Discovery-Alpha dodge astronaut's space junk. Do we as a people know how to pollute, or what? A 1999 study estimated there are some 4 million pounds of space junk in low-Earth orbit. I just watched a program on The Learning Channel that also showed how the Cosmonaunts on Mir would simply jettison their waste into space...traveling 18,000 MPH!!! And I thought flipping a cigarette butt out the car window was bad....
posted by Sal Amander (11 comments total)

 
This could eventually lead to a cascade effect that would make getting into orbit impossible for the forseeable future.
posted by thatwhichfalls at 12:51 PM on March 14, 2001


We have been really bad about polluting up there, but the real problems are the objects too small to track. The paint flecks and fuel droplets that can hit with the same force of a car at 100 MPH.

Luckily there is a lot of space up there, so if we start paying attention now we should be OK.
posted by Nothing at 12:57 PM on March 14, 2001


I'm very surprised to hear that about Mir, Sal. My understanding was that space junk is taken very seriously (at least by the US). When they did that 9-hour spacewalk the other day, I remember hearing that two small items were dropped. One they recovered, but the other they will monitor until it burns up some months from now. If the Russians are just dumping stuff left and right, what's the point of our diligence?
posted by jpoulos at 1:01 PM on March 14, 2001


I can't believe they let an opportunity like that slip by. The astronaut drops a tool and it comes back to them, and they don't send him out to retrieve it? The wastrels.

Besides, everyone knows what a pain it is to lose your
"12-by-6-inch viselike tool" in space. "Sir, requesting permission to use the shuttlecraft to stop by Home Depot, sir."

It seems to me that I heard something years back about Lloyd's of London offering insurance for deaths caused by pieces of Skylab falling. Around the same time, I saw a report on TV that said there was only one documented case of a person being hit by space junk. I think it was a woman who got hit by something that crashed through her roof. She survived. Of course, my recollection could be faulty.

I'm wondering how the amount of space junk falling to earth compares to meteors, over a given time period. I'm guessing that it's not something I have to lose sleep over.

posted by anapestic at 1:26 PM on March 14, 2001


I am an ass who comments before reading the link. Please beat me now. :-)
posted by jpoulos at 1:57 PM on March 14, 2001


This is one of my arguments about populating other planets. Let's clean up the one we have before we go and screw up another one. Or pollute space for that matter.
posted by terrapin at 2:17 PM on March 14, 2001


anapestic: Lloyd's, of course, is a group of insurers with a sense of humor. Nevertheless, the Outer Space Treaty requires countries to compensate any injury or damage due to space junk, so Russia has reportedly taken out a $200 million insurance policy against Mir's demise.

That lady wasn't hurt by space junk; it was a meteorite, and it bruised her leg pretty badly.

As for the clamp, this should be taken in stride. The tool would contact the space station/shuttle orbit with approximately the same velocity with which it left -- in other words, a heavy nudge. Still, you don't want to take any risks on orbit. (The greater danger is something moving at a perpendicular angle -- then you get the full force of the 17500mph angular momentum.) It's a fairly large piece of equipment (as such things go, about the size and shape (and purpose) of a large metal clamp. The orbit it has will decay, and it's estimated it will burn up in the atmosphere in about a month. The ISS, meanwhile, will be reboosted by the shuttle before it leaves, putting it several miles higher up.

Most Mir trash went into a Progress cargo ship, which then automatically deorbited itself, burning up on re-entry. They did eject some things, like human waste, especially when the Progress ships became overloaded (in later years they didn't replace them often enough), but again this stuff mostly decays fairly quickly from that initial altitude. And of course they lost things on spacewalks, too.

MOST of this stuff decays quickly. It's the stuff in higher, or chiefly parabolic, orbits that stick around a long time (like Vanguard 1 -- going strong since 1957!). And the worst of it is that it happens even when you have the best of intentions. Even so, the risk seems to be fairly low, thankfully: only a handful of shuttle flights have returned with serious damage to a window.
posted by dhartung at 3:05 PM on March 14, 2001


You know, if I went out for a spacewalk and was hit by someone else's 15 year-old digested and ejected breakfast flying at 17,500mph, I would have to go straight back to bed because it obviously isn't going to be my day. That is, if I was able...
posted by fooljay at 3:11 PM on March 14, 2001


Actually, someone has been hit by falling spacecraft debris. I read once (I think it was in Arthur C. Clarke somewhere) that at the rate we're going, we're going to have rings like Saturn comprised solely of crap we've left in orbit.
posted by OneBallJay at 3:22 PM on March 14, 2001


Fooljay, you funny.
posted by acridrabbit at 5:27 PM on March 14, 2001


As mentioned, the stuff in LEO will fall out of the sky in fairly short order. And they won't hit the earth; most of it is much too small to survive reentry. When Skylab came down, which was the single largest thing to ever reenter and be destroyed before Mir, only a few pieces hit the ground.

Satellites in geosynchronous orbits have a lifespan which is a function of the amount of maneuvering fuel they carry. It's necessary to use fuel constantly to maintain orbit; and after a few years they run low. At that point, the remaining fuel is used to put the satellite into an eliptical parking orbit which has been designated for that use. All the old dead geosynchronous satellites are in it.

But they'll be up there for a long time (hundreds of years, maybe). Orbits that high don't decay very rapidly. And there isn't enough fuel to change their orbits enough to make them hit the earth and burn up.
posted by Steven Den Beste at 10:21 PM on March 14, 2001


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