Don't get it.
Why not just de-orbit space junk and be done with it?
Move space junk with laser shots
More than a decade's work could be closer to payoff for Canberra company EOS Space Systems, which last week told the Sixth European Conference on Space Debris that its laser systems could help move space junk out of the “danger zone”. Before you start imagining orbiting satellites bristling with enough weaponry to knock out …
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Monday 29th April 2013 04:31 GMT Martin Budden
Re: Don't get it.
De-orbiting is an active process which involves applying force to slow an object enough for it to drop into a low enough orbit that atmospheric drag takes over and finishes the job. Items of space junk do not carry their own propulsion systems to apply the necessary slowing force (new satellites do, it's in the rules these days). Pushing an object with a laser from below isn't going to slow it.
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Monday 29th April 2013 06:54 GMT imanidiot
Re: Don't get it.
Actually, it IS possible to deorbit by pushing away from the surface of the earth. This action changes the excentricity of the orbit, and if done at the right places can lower the periapsis and raise the apoapsis. Decenter an orbit enough and the periapsis will be at a point where atmospheric drag can take over. (It is however far less efficient than a dead on retrograde burn at apoapsis.)
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Monday 29th April 2013 12:53 GMT No, I will not fix your computer
Re: Don't get it.
>>Actually, it IS possible to deorbit by pushing away from the surface of the earth.
It's very unlikely that what you are suggesting could be practically applied for several reasons, there's little atmosphere above 100km, whereas the LEO junk is a problem around 900Km+ so you'd need top create a very eccentric orbit for periapsis to dip into the atmosphere, even if possible (and the article talks about, tiny nudges, 100m movements) this would make the debris itself harder to track and would potentially create a significanlty faster (during periapsis) object covering more danger zones, your laser would also have to be (coincidentially) at (or create a stable) apoapsis or you'll just create a circular orbit.
Nice idea, just not for the distances we are looking at.
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Monday 29th April 2013 15:15 GMT Anonymous Coward
Re: Don't get it.@Martin Budden
"Pushing an object with a laser from below isn't going to slow it."
OK, so what if you fire the beam at a non-vertical angle? Obviously you'd be losing power through a longer atmospheric path, and then you've got both vertical and orbital components. The vertical will push the debris up, but could the slowing down of the debris and resultant gravitational pull be sufficient to offset that vertical component?
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Monday 29th April 2013 03:29 GMT Don Jefe
Disintegrators
We've got these Electro Arc metal disintegrators in our prototyping shop & I've often wondered why those couldn't be used to eliminate space garbage. Most satellites and space program remnants are built of fairly flimsy materials so even small disintegrators could destroy or destabilize stuff.
I know it isn't really feasible (for a lot of reasons) but the disintegrators are super cool in both function & appearance & it would be neat to have them repurposed and flying around dealing with orbiting junk.
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Monday 29th April 2013 10:19 GMT BristolBachelor
Re: Disintegrators
I assume that what you call "disintegrators" are what I know as plasma cutters, which just melt the metal where you point the torch, allowing you to cut things out (and of very think metal too!) If so, yes, cool.
However, if you melt the metal in space, it's still there, just as molten metal, still travelling in the same direction with the same speed. Then it re-solidifies, so it's still there. Maybe instead on a big piece (that you can esily track), it becomes a rain-shower of thousands of smaller pieces. Think about a system that turns 1 ton of car into 1 ton of little bullets to protect pedestrians...
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Monday 29th April 2013 10:30 GMT Ru
Re: Disintegrators
We've got these Electro Arc metal disintegrators in our prototyping shop & I've often wondered why those couldn't be used to eliminate space garbage
Cos you've got to be ablto put your disintegrator in close proximity to each piece of junk. This requires getting a spacecraft up into a fairly close orbit and giving it some quite precise manouvering capabilities and a big delta-v reserve. This is what is known in the trade as "very, very expensive".
If you can get that close to litter, you'd be better off bagging it and then throwing the bag, or yourself, down into the atmosphere when you're finished. There are other projects in existence which are trying to do exactly this.
assume that what you call "disintegrators" are what I know as plasma cutters,
I was thinking more along the lines of plunge EDM machining (you can get simple ones for destroying broken taps and bits in expensive workpieces), but perhaps you're right. In either case, stuff might be 'disintegrated', but it ain't annihilated.
Anyway, plasma cutters in space are more correctly known as "rocket engines", so they'd be a jolly inconvenient tool to use. EDM needs a dieletric fluid to work, too... not an easy thing to handle when you're squirting it out into a vacuum under microgravity!
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Monday 29th April 2013 11:29 GMT Don Jefe
Re: Disintegrators
They are EDM plunge type devices. Like you say, we use them for removing broken tooling (mostly taps). They make a hole down the center of the broken tool and allow what remains to be easily removed.
Like I said, I know why they wouldn't work, it just sounded cool: "Deploy the disintegrator" in a space setting just sounds like fun.
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Monday 29th April 2013 04:49 GMT Martin Budden
A constellation of mirrors!
I've said it before and I'll say it again...
Several thousand lightweight mirror satellites spread out in orbits around earth, so that reflected sunlight from several hundred at a time can be directed onto one side of a piece of junk. This is basically Archimedes' Death Ray IN SPAAACE!
Because each mirror satellite is lightweight (less than 1kg) and compact when folded, several thousand can be sent up with a single launch, making the project affordable (in space terms anyway).
Each satellite consists of the following:
- A triangular foldable foil mirror a few metres across (think of those survival blankets, they are even called space blankets!)
- three long carbon fibre tent poles, one to each corner of the mirror, and joined with springs in the centre so the mirror is unfolded and stretched taut when the poles are released
- small solar panel & battery (not much juice needed)
- three small motors set at right angles to each other to change the orientation of the satellite
- control microchip
- radio receiver
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Monday 29th April 2013 05:49 GMT Kugutsu
Re: A constellation of mirrors!
You would also need a motor and enough fuel to keep your mirrors on-station. Otherwise the sunlight they are reflecting will pretty quickly push them off-course far more than the (I assume) much heavier satellites they are trying to shift. Also, surely sending up several thousand new bits of stuff is a bit counter-productive...
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Monday 29th April 2013 07:31 GMT Rustident Spaceniak
Re: Lasers, check.
The sharks are too scared. That's because the Brits are already sharpening their space harpoons:
http://www.flightglobal.com/news/articles/in-focus-astrium-engineers-take-a-shot-at-space-debris-385004/
We gotta figure out a way to mind-meld with the sharks first, take their anxiety away. So we're starting with small fish, working out way up.
http://www.nasa.gov/mission_pages/station/research/news/aquatic.html
Mine's the one with the shark tooth buttons.
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Monday 29th April 2013 14:57 GMT Rustident Spaceniak
Re: Re: What happens when a pigeon flies through the beam of a 10kW laser?
Ideally nothing happens to the plane, because the ranging&tracking station had just switched the beam off a minute to a microsecond before contact.
Now, if that was a stealth plane with no radio communications, no published flight plan, no TCAS equipment (that the laser ranging system could listen to) or ADS-B, and no clue about the location of the frikkin' laser (which I guess would be protected by a no-fly zone), at night...
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... it would get the 10kW through some 10km or so of atmosphere, passing over its structure at a rate of about 250m/s, and probably warm up a bit.
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