Really? That seems like about the most inefficient possible way of doing it. Considering the hundreds of thousands of bits of orbiting junk, and the miniscule size of most of them, I’d have thought that some sort of sweeper would work best. Something with a wide magnetic field, or a physical blanket that can stretch over a wide area to catch things, then drop them into a decaying orbit while the sweeper remains to continue it’s job. Am I missing something?
I think you might be missing something, though I’m far from an expert on this.
An object in orbit ts moving at a great speed. To change its altitude or direction requires a great deal of energy. Also, the junk is all moving as well. Sweeping it up would be like sweeping leaves out of your open garage during a hurricane … Sort of.
Which is why I thought this was inefficient. How much energy does it take for this thing to match orbits with something, and then take it down? One sattelite for one piece of junk doesn’t seem like it could ever be economically viable. I know that if you slow something down, it falls into a lower orbit. If there was some way to rob even a little energy from some of the junk, that could cause it to descend & burn up.
Maybe this thread should get referred to Phil Plait- I bet he could illuminate the issue.
I think the point is to get at (and remove) the larger pieces of junk before they hit something and become smaller bits of junk. Thus, it is trying to be efficient by PREVENTING a worse situation. Dead hardware that is physically intact but out of control can be removed this way.
I’m with Artor on this one… Seems like a very stupid approach. If we had a space-elevator/cannon/whatever and could get the cleaner modules into orbit easily, OK. But we don’t. And it does nothing about the small debris.
S. Williams’s point about needing to de-orbit the larger stuff is valid. But I would think that attaching a very small booster (solar powered ion would be cool) would do the trick. The main craft could carry a number of such little boosters and attachment isn’t all that difficult since the booster could be on the end of a cable.
A real sweeper is a much more interesting prospect. Lots of cool ideas around how to tackle that and no clear “winner” (which would definitely actually work) yet. That is the sort of thing EPFL should be having their students working on instead… Knowing just a little bit about the institution, my bet is that the potentially useful or at least cool part of this CleanSpace One idea is software making it autonomous (just a guess though).
The main craft could carry a number of such little boosters and attachment isn’t all that difficult since the booster could be on the end of a cable.
Again, I’m not an expert on this, but here’s my question: You can launch this main craft to meet up with a given large piece of junk, and attach the rocket thingie that makes it deorbit. But then, how do you get to your next target? Unless it is in a very similar orbit, that will require considerable energy. It would seem that a space-junk-catcher would never be able to manage space junk orbiting in the opposite direction or even at an angle of more than a few degrees off the main craft’s original orbit, or junk that is going at a speed any faster or slower.(speed and altitude are linked, so sed/speed/altitude/g)
I don’t know how this cleanspace one thing would work exactly, but it may be that shooting small grappler/deorbiters at the big pieces one at a time (or a few in one lauch with slightly different tertiary launchers giving them different altitudes) might work better.
These things look like they are floating around in space all nice and calm-like but they are actually going as fast as bullets but are much bigger.
To me, the most interesting aspect of all of this is the fact that the version of humanity that is the most enlightened and self aware (one would think) has committed as bad a “tragedy of the commons” move as anyone ever has.
Thanks, big brain!
Uh, guys, this is not real. This is a gag.
Just burn the shit with lasers. Done. Crack a beer.
Nuke near space, and let orbital mechanics sort it out. (Assuming we can get those mechanics into orbit.)
Re: Greg’s #6 post…
You are certainly correct that moving from one orbit to another takes a lot of energy. But most old satellites (the ones which weren’t designed to de-orbit themselves) are in very similar orbits. The class of orbits which take the least amount of energy to achieve is what I’m talking about (nothing will be going the “opposite direction” since it would be prohibitively costly to put it there in the first place.) But again, you’re right that it takes a lot of energy to adjust even a few degrees… that is still a lot less than getting into orbit in the first place though.
The idea I was floating was for the cleaner craft to use low impulse (aka slow but very efficient) engines and take it’s sweet time to de-orbit a number of pre-defined junk objects. There is some big junk which isn’t suitable to this approach (very different orbits) of course.
A bunch of very small craft with grapples each going off to de-orbit it’s own target probably does makes more sense than a single craft visiting each target. They would probably be launched in clusters. The key is that these would be VERY SMALL craft. This appears to be what the CleanSpace One design is actually about now that I read a bit more about it. The grapple system seems like it could be simpler though… these targets are rotating in all sorts of ways and a rigid grapple seems ill-advised.
Anyway, small debris, which requires some sort of sweeper, is a much more interesting problem IMO.
Well, there s still the giant magnet idea.
Hmmm… Just brainstorming here, but I wonder if a main sattelite “mothership” with a number of smaller robotic rockets could be useful? The main sattelite could casually cruise around in it’s designated orbit, close to a crowded lane of junk, and fire off a small rocket towards a target. The smaller rocket would be easier for matching velocities, and it could grapple & drag the junk down to a fiery death while the mothership continues to look for more targets..
The thing is the larger objects aren’t as big a problem as the many small objects. That means spending a lot to deorbit very small things.
One idea I had was a satellite in a retrograde orbit that uses an air cannon to blast clouds of ice crystals into the path of oncoming objects. An impact from even a tiny crystal would likely deorbit the target.
It is correct that this cannot solve the entire space debris problem, but it’s not actually meant to. One major omission from the clip is that this is intended for a very specific sort of space debris: dead nanosatellites, and particularly CubeSats. In fact, this would itself be a CubeSat, or at least very close to that in scale. Right now, operators of CubeSats rarely have any means of deorbiting their spacecraft; these things don’t generally have any propulsion (though one of the recent Vega maiden flight payloads carries a solar sail, which they intended to use to demonstrate CubeSat self-disposal). The idea is that CubeSats are relatively cheap to launch, since they basically hitchhike on other launches, so this trash collector would also be cheap to launch (in theory). A CubeSat operator could buy one and launch it to remove their spacecraft at the end of its mission.
It still remains to be seen whether the universities which currently operate the vast majority of CubeSats would be interested or able to do such a thing to tidy up after themselves, but it could prove viable for this specific application. I do not think it would be viable for larger targets, such as dead payload fairings, spent rocket stages, and large defunct satellites. At least, not yet. The deorbit spacecraft would have to be a nanosatellite to be financially viable, and I’m not convinced any of those would have the performance needed to clean up large debris.
A cubic kilometer fine-fibre cloud could soak up the small stuff. A one-ton payload could could expand to HUGE. It would be designed to ablate to dust within a few months of UV exposure. The very thin trace of air up there would very slowly reduce its altitude, bringing nuts, bolts, spanners and other shrapnel with it.
The thing is the larger objects aren’t as big a problem as the many small objects. That means spending a lot to deorbit very small things. One idea I had was a satellite in a retrograde orbit that uses an air cannon to blast clouds of ice crystals into the path of oncoming objects. An impact from even a tiny crystal would likely deorbit the target.
@ ^ Satellite Receiver | April 17, 2012 2:01 AM
But wouldn’t those clouds of ice cyrstals be a menace to other functuional satellites and spacecraft in themselves? Isn’t that just adding to the problem?
Or would the ice ctyrstals melt / sublimate away rapidly enough for this not to be an issue?
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