Wednesday, July 09, 2008

Space Junk

From IEEE Spectrum Magazine:

source: IEEE Spectrum

Instead of floating inside an orb, these flakes, some of the solar system's newest ornaments, dance around it. The ­dusting comprises active satellites and tens of thousands of space scrap--including wrenches left behind after extra­terrestrial home-repair projects, bits of long-abandoned satellites, and actual trash bags stuffed with the detritus of manned space flight. The number of pieces of junk in this orbiting garbage dump, which circles Earth at speeds up to 7800 meters per second, is ­multiplying; when the particles collide, they break into smaller pieces that some believe could eventually make it too risky to put ­satellites into orbit or even to explore outer space.

(via reader David H.)


OBloodyHell said...

This has been a concern for decades. I personally suspect that, if a Skylab can't sit up there indefinitely, then it's highly improbable that space junk has an indefinite lifespan, either. There are a lot of forces that make orbits unstable, and there is a lot more drag than people realize at 300-500 miles.

I'm sure this problem isn't utterly trivial, but it's more a longer-term question we have to decide about just tossing stuff overboard, too.

First off, we probably ought to be armoring longer-term structures better than we do, but that involves adding mass which we don't have a good source for at the moment (thanks to Clinton, who shifted every dime of the "Peace Dividend" into HRW programs rather than spreading it around and/or returning a good chunk of it to us all in lowered taxes) -- we need to put a mass driver on the moon and get some real manufacturing going. Apparently we've decided to abandon space to the Chinese, however.

Second, this whole "space should be safe" crap needs to go. As RAH put it, "Pioneering involves finding newer and ever more horrific ways to die". It's not going to be "safe" for a long time. We have to have a much better baseline of what can go wrong before we can cover all the bases on adequate safety and design features. People are gonna die. The surviviors are going to just live with it. If you don't want to accept the risk, then you should stay a groundpounder.

Robin said...

What a coincidence - I'm currently watching a Japanese anime series called Planetes. The premise is that in the year 2075, space junk has become enough of a danger that massive resources are devoted to cleaning it up. It's hard sci-fi -- no magical tech, gravity is generated by spinning sections of the space station, and when there's no spin, people are seen maneuvering in microgravity (a.k.a. "zero-G"). Really rather good.

And then I stumble across this blog post. Can't help but be amused at the coincidence.

likwidshoe said...

The concern is an Ablation cascade.

OBloodyHell said...

> The concern is an Ablation cascade.

Actually, the solution for this is obvious, but ass-backwards from that suggested in the wiki piece:

One technology for the bigger fragments that can be tracked is the laser broom, a multimegawatt land-based laser that could be used to target fragments. When the laser light hits a fragment, one side of the fragment would ablate, creating a thrust that would change the eccentricity of the remains of the fragment until it would re-enter harmlessly.

This tech could be used against pretty much anything, at every side (the ablation thing can slow down everything if it hits at the proper angle in the first place -- and if it doesn't, then you just have to hit the same thing, again, for longer, from the correct angle), and this doesn't really require a laser if you started from space in the first place. You only need a laser if you need to punch through the atmosphere.

I.E. -- this would be stupid.

Put a good set of solar mirrors up there, with proper aiming/targetting measures and just use the sun to power the "broom". Since energy isn't a real problem in this regard, you can do it as much as needed to hit stuff at the angles required to degrade their orbits, and this will work on anything large enough to actually worry about.

The mirrors can be made on the moon or in space from lunar materials -- no need to ship up much more than a basic manufacturing plant (can be small, the mirrors in question can be mylar-thin) and a railgun to boost the lunar materials into orbit.

In short, this is itself a good idea since one of the underlying sideprojects is something we should have done 25 years ago.

I suspect the Chinese will do it as soon as they decide they need to put money into a major national prestige project -- which space is going to be the most likely target of.

That we have conquered space and yet gone no further is the worst checkmark against this nation's future. It's as though the Louis & Clark expedition happened, but there was no Westward Expansion, much less any declaration of Manifest Destiny.