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The NY Times has a good story about a push for international action, via the UN, on the growing problem of space debris. Includes a pretty picture of a space shuttle window that got nailed by a fleck of paint.
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http://www.nytimes.com/2003/02/18/science/space/18 TRAF.html?ex=1046149200&en=f39397b7a99dc415&ei=506 2&partner=GOOGLE
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Tuus crepidae innexilis sunt.
This is pretty old news but it's got better pics. Norad has been tracking space trash for decades. Fact of the matter is, there is trash up there, yes it can hurt you or the shuttle, or the hubble, etc. But the odds are very slim for most orbits. The hubble got hit with a little piece once, but the odds are pretty slim anything we send up will get hit by debris.
what? what I thought we were in the trust tree in the nest, were we not?
This is the "critical mass" problem, where at a certain point all the junk colliding with itself creates a self-propagating chain reaction. This has two effects - more smaller bits are harder to track, of course (particularly because there's a resolution limit that determines the smallest size per distance that ground radar can track), but also a spreading of the material into wilder orbits and outside the two bands where it's currently still concentrated. The shuttle & ISS altitude, for instance, is relatively clear right now. Once the chain reaction starts (and some people think it already is in the chaotic early stages) this will no longer be true, and all space travel will become a lot more difficult.
The NYT article only slightly alludes to this with the "10 or 20 years" bit, but it is the real problem. As you note it's a question of linear vs. exponential growth - manageable or unmanageable. There is a tipping point, and regardless of where it is, it's folly to keep approaching it without SOME sort of cleanup scheme. So save your chewing gum; it's going to come in handy one day for the great space sweepup.
I hate to appear snide ( when I don't mean to that is), but go out on some dark night. Look up.
You'll see stuff.
Ok, let's make it a little more interesting. Go out on a night that isn't so dark, because there's a half moon out. Bring a pair of binoculars with you.
Look at the moon. Notice that it's all coverd with holes. Those holes were caused by things in "empty" space hitting the moon. Amazingly big holes can be made by surprisingly small bits of stuff if they hit with enough energy.
The weight of the earth actually increases by tons every day from all the stuff in "empty" space falling on it. That's not counting the manmade stuff that's out there circling around waiting for its time to return to earth.
Space isn't empty, it's just drawn that way.
KFG
One would HOPE that
that posters have a vague familiarity with the UN before launching such a broadside.
foldplay your photos won't know what hit them.
Am I the only person that's noticed all you have to do is slap ?partner=GOOGLE on the end of a NewYork Times URL and it won't force you to register? Point in case for this article:
8 TRAF.html?...&partner=GOOGLE
http://www.nytimes.com/2003/02/18/science/space/1
Here is the NASA site with impact photos of the Mir, the space shuttle and another satellite called the LDEF: http://hitf.jsc.nasa.gov/hitfpub/problem/actualimp acts.html.
::.. check out some Cell Phone Reviews
In order for a space garbage collector to work, it would have to go chasing after a large number of peices of junk moving in different orbits. In order to catch a particular piece of space junk, it would have to both match the junk's velocity and possition, then fire up its engines again and go after some other peice of space junk. Even if one could come up with a very efficient algorythm for chasing down the junk, the garbage collector would have to have its engines on nearly all the time. If it used a traditional rocket, it would run out of fuel in at best a couple of days. If it used the microwave heated xeon type it would be collecting garbage for centuries if not millenia.
Galium Arsenide is the material of the future, and always will be.
screw sized projectiles at maybe 1500 miles an hour
Actually, I had read somewhere that manmade space junk orbits at around 22,000 miles per hour, while natural space junk orbits at around twice that speed. So depending on the direction of your orbit, and the space junk's orbit, you could theoretically be coming up against some space junk at around 88,000 miles per hour.
Kinetic Energy = 1/2 * mass * velocity ^ 2
um, its a bit more dramatic than that. You should recheck your calculations. 60 mph is about 26 m/s, orbital speed is approximately 7600 m/s for a bolt mass of 50 g (.05 kg or about .11 lbs) the kinetic energy is roughly equivalent to 4000 kg at 60 mph or about 8 tons ( in lbs tons) so imagine getting hit by an 8 ton truck that has the cross section of a bee. It would go right through a space shuttle or anything inbetween.
As previously stated, the problem is when that pellet is going 20,000mph in the opposite direction of the space craft. 40,000mph whammo.
On a related note, anyone here ever play RIFTS? I remember getting the expansion book describing whole space colonies which hadn't contacted the surface of the Earth for hundreds of years due to massive interweaving clouds of space crap that destroyed any ship attempting to land (or presumably move within communication distance).
Green-voting, republican-registered, socialist-libertarian.
Sending into the sun, you have to apply lots of horizontal thrust to reduce the angular momentum imparted from earth to put the garbage into a collision course with sun, instead of orbiting around it.
Evicting from sun's gravity involves adding lots of kinetic energy to give the garbage escape velocity (no cheating and using slingshot effects).
Even with no cheating, it still requires less energy to kick something out of the solar system than send it into the sun. Interesting little problem, we solved it in my classical mechanics class many moons ago.
But, a highly elliptical orbit will have an object moving SIGNIFICANTLY faster at it's perigee (closest point to sun) than a corresponding circular orbit at the radius of the perigee. Kepler's 2nd law (equal areas swept out in equal times).
Just for completeness, Kepler's 1st law says bound gravitional systems move in elliptical orbits, with the gravitational source at one of the focii.
So, yes, it is quite possible that at any point one can encounter an object moving significantly faster.
This is addressed to all the posters who posted varients of "Why don't we just catch all the junk?"
Since you don't understand the problem, allow me to offer to help you understand it.
Come to my house. We'll go into the back yard, and I'll shoot at you with my AR-15. You catch the bullets. That's MUCH easier than catching orbital debris - the bullets are much larger (40 grains is roughly 2 grams) and MUCH slower (3600 feet per second is roughly 1 km/sec). Also, you will know ahead of time where the bullet will be - I'll make it easy and aim right at you.
Now, when you can catch those bullets, you can move up to orbital debris - much smaller, much faster, and moving on unknown trajectories.
"But we'll just use a big Kevlar net! We won't have to know where the bullets are heading!"
Fine. Here's your Kelvar net, about 1km on a side. It will only take about 1000 years to catch most of the debris, since "Space is big. Really really big. You can't believe just how mind-bogglingly huge space it".
To simulate the launch, let's go to Colorado Springs. I'll pay your way into Pike's Peak. Go to the top of Pike's Peak with the net - it's only a couple of tons. No, you cannot drive - you have to walk. I'll wait. That will help you understand the COST of putting your big net into space.
DON'T take what you see on Star Dreck as reality - space is HUGE, junk is SMALL. This is not a simple problem.
www.eFax.com are spammers
Getting a heavy object to sink, and yet still stay bouyant enough to surface is a whole hell of a lot less an engineering challenge than getting a big-ass and extremely robust space vehicle to 200-500 miles ASL. You'll notice that an old Los Angeles class attack submarine, with VERY heavy nuclear power plant ran about $600 million in 1970's dollars, and yet the Shuttle runs about $2-$2.5 billion in 1980's dollars. Hell, even the new Virginia class submarine only costs $2billion in fy2000 dollars and it weighs a LOT more than the Shuttle's 100 someodd tons.
But most submarines don't have to worry about 20,000mph paint flecks and broken satellites flying at them at high speed. The worst external threats they have to worry about are running into ships, other submarines, getting hit with exploding torpedos, and running into terrain.
But that's why we need space elevators. Unfortunately, to have space elevators, we need lightweight chemical/nuclear launchers. And those will ALWAYS be fragile.