From: Anders Sandberg (asa@nada.kth.se)
Date: Thu Apr 29 1999 - 04:59:40 MDT
Karsten Bänder <Karsten.Baender@ivm.de> writes:
> > > ...This now-junk could be recycled to biuld up something new. This junk
> > > travels around at highspeed, but anyway, a space vehicle
> > orbiting our planet
> > > would do this, too...
> >
> > Yes, but the problem is, the space junk is in *different* orbits, each of
> > which have enormous velocity relative to each other.
>
> Well, a space vehicle is able to change orbits, so this poses no problem. As
> there is only a finite number of orbits, you could, one by one, skim these
> orbits.
Unfortunately, things are not that simple. The number of possible
orbits are infinite, although only some are of real interest (such as
the geostationary orbit). But changing orbits for a spacecraft costs
energy and propellant, so skimming them all is extremely hard.
> > > ...but as most of this junk is magnetic...
> >
> > Almost none of it is. There may be a *little* iron, but it is
> > mostly aluminum.
>
> As far as I know, every satellite contains at least some iron. I do not know
> if this would be enough to attract it. I am not an engineer, but I know
> that, though planes are built of lightweight materiels, they, too, contain
> enough iron.
Yes, but most of the space junk is not entire satelites, it is
everything from pieces of wreckage over dropped spanners down to paint
fragments. I'm quite sceptical to the claim that all of it would
contain magnetic materials, and that they could be easily caught with
a magnetic field (what is the range of an effective magnetic field in
this case? I get the impression that matching orbits with junk can be
rather expensive and dangerous, and you have to go fairly close to it
to catch it. A field would be better than a boom, but still getting
too close with a valuable spacecraft.
> We'll see. But the problem is getting urgent, though, as some orbits are
> nearly full by now and we cannnot afford to wait another 50 years 'till we
> have a technical solution for it. Worst-case we'll do it the old style:
> Replace tractor beam with robotic arm, and you'll have a system which could
> be ready for service in a short term.
Yes, but only for larger junk. Still, it is a serious problem and we
need a solution.
-- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! asa@nada.kth.se http://www.nada.kth.se/~asa/ GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y
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