Could space debris destroy all hope for human space travel?

General Questions
#1

Just saw a CBS report on the possibility that space debris could potentially have punched a fatal hole in Columbia, though of course they have no idea if this was the case.

But it does raise a rather scary question. Currently, there are millions of bits of debris in orbit, and many of them are large enough to cause serious damage. Of course, that’s still low enough that we can avoid the larger bits (though several shuttle missions have been hit and damaged). Yet because they travel at speeds of something like 20,000 miles an hour, if they are large enough, there is litterally no way for us to sheild against an impact with modern materials. At some point, it must get to be impossible to navigate: the peices move too fast to steer around, and too hard to predict or track them all.

So I’m thinking about two possible scenarios.

One is simply that over a long time, we build up so much debris that space above earth becomes unavigable. The second would be a major space disaster or two (say, a nuclear rocket on its way to Mars blowing up) that would leave tons and tons of debris at once.

In either case, are such scenarios imaginable to the point where humanity’s safe access to orbit would be ruined: where any craft going up would face a high risk of being ripped to shreds by debris? I suppose it would take knowing how long this debris generally stays up, and of course the absolutely unimaginable amount of space to be filled (of which I’m not sure how to calculate, not knowing the altitudes for normal orbits or the size of the band where most orbits take place).

And could someone deliberately destroy our access to space by launching unmanned rockets filled with debris and blowing them up in space? How far along would the space program of a nation need to be to do this on a large enough scale?

#2

Some info on space junk from space.com, as well as another interesting article here.

The “build up over a period of time” would surely be counteracted, to an extent, by the Earth’s gravity and orbit degradation of the debris back into the atmosphere, falling as meteors do.

#3

But Geostationary orbits could be comprimised for centuries by a deliberate attempt, no?

From the second article, we find: “Each decade that it is in orbit, according to a recent study, the station will have about a 20 percent chance of undergoing a “critical penetration” that could kill a crew member or destroy the station – and the chances will increase as more objects are launched into space.”

And that’s just with the current level of debris.

The article also notes that two orbits may already have enough mass to put the potential risk of collision at a point where it could happen every few years to something in those orbits: and it takes about a hundred years to clear out.

I guess then my real question requires me looking at: what orbits are most important for human space exploration, how much mass would need to get in orbit in them for a normal cascade, and how much to make those orbits too dangerous to attempt at all, and finally whether it would be plausible for a country to be able to put that much mass into space quick enough.

#4

Anyone interested in inventing a way to speed the process of cleaning up this stuff instead of waiting for it to just degrade into man made meteorites?

#5

I believe there have been proposals for doing just that. IIRC, some of the SDI proponents suggested ideas involving putting up foam balls and the like to “absorb” such microjunk. Arthur C. Clarke talked about the necessity of doing something like this before trying to erect a “space elevator” in The Fountains of Paradise. There have been some SF writings on the topic (including one book with a wonderfully graphic picture of Saturn-like rings – of garbage – in orbit). and one program on this on one of the cable channels – TLC or Discovery. Certainly people have discussed the problems of man-made debris in orbit, how to clean it up, and the possibility of deliberartely using it as a weapon to keep people out of space. (See the late Danial Graham’s novel of a couple of years ago).

#6

A third possibility is that someone chooses to deliberately muck up low earth orbits in order to limit surveillance by unfriendly nations. There’s a discussion of the possibilities scattered throughout these threads:
Astronauts and space debris
satellite defense (or is it offense?)

#7

One scientist has proposed a robotic satellite which would move around in orbit, cutting up debris and using it to repair itself and build replicas of itself. Any debris that it couldn’t use, it would collect and then send into Earth’s atmosphere to burn up. No idea if he did any more than just the casual sketched idea I’ve mentioned.

#8

This ‘problem’ is exagerated by the media. Space, even just the volume of the orbital paths around the Earth, is extremely vast compared to the volume of stuff we’ve put into orbit. There is not really a lot to worry about.

#9

I know this may sound stupid, but how about launching magnets into orbit to catch the metallic debris into large balls whcih would be more easy to avoid? Is such a thing even remotely feasible?

#10

Most of the debris is non-magnetic: aluminum, titanium, stainless steel, carbon fiber, ceramic, mylar foil… Plus a magnet that large would be more of a danger than the debris, if it got near something you didn’t want it to stick to.

#11

I should think that most of it is non-magnetic. Light metals such as aluminum, magnesium, titanium where needed and, of course, plastics of all sorts. I suspect that every effort is made to use something besides iron, or cobalt or other such material.

#12

Well, AndrewL, great minds eh?

#13

Hail Ants is right. There is a huge amount of space up there and relatively little debris.

The risk of a piece hitting a spacecraft (eg satellite) has been assessed by satellite companies. It is very low.

#14

Isn’t it possible that all space stations and space shuttles could be mounted with a laser and a good radar, capable of tracking and deflecting any dangerous debris?

Couldn’t space debris be destroyed by laser, one by one? Or would this lead to more debris?

#15

You have to remember the immense vastness of what we are talking about. Think about the entire surface of the Earth, only thousands of miles thick, and even larger in area because it’s got a diameter hundreds of miles bigger. Saying you could just build a satellite to sweep it up is kind of like saying you’ll just build a big truck and sieve out the Sahara to find your wedding ring. Except 100,000 times bigger.