Using Lasers and Water Guns To Clean Space Debris

WSJdpatton writes "The collision between two satellites last month has renewed interest in some ideas for cleaning up the cloud of debris circling the earth. Some of the plans being considered: Using aging rockets loaded with water to dislodge the debris from orbit so it will burn up in the atmosphere; junk-zapping lasers; and garbage-collecting rockets."

Comments

Re:Water....

[smooth wombat]

One cubic foot of water is around 60 lbs.

I thought that number sounded a bit high as a gallon only weighs about 7 pounds, but sure enough, a cubic foot of water DOES weigh around 60 lbs. 62.42796 pounds to be exact. And a gallon is actually just over 8 pounds.

Re:Huh?

[Colonel Korn]

Since space is a "near" vacuum wouldn't the water flash to steam instantly and be useless?

The enthalpy of vaporization for water is very large. On exposure to vacuum, immediately the water will begin to boil. This will very rapidly cool the water so that most of it ends up freezing (the enthalpy of fusion is comparatively much lower). Not only does this make mathematical sense, but it's witnessed daily on vacuum lines in labs.

Re:Water????

[Colonel Korn]

Not only would lofting water into space be a colossal waste of energy and water, it would only exacerbate the problem!

IMHO the only 'clean' way to deorbit debris is to add energy to the debris in the retrograde direction without using additional mass, which means photons. Laser pulses could do it either by radiation pressure directly (huge laser), or by pulses that ablate the debris slightly (creates tiny beads of additional debris).

Electron/proton beams would work as well, as would alpha particles, but they'd pose a risk to humans in space. In fact, using charged particles might induce a charge on the debris that would then help direct the debris toward it's doom (debris vector, Earth's magnetic field, right hand rule....whatever).

You do know that electrons/protons/alpha particles have mass, right?

Re:Space Quest

[oneiros27]

Unfortunately, most of the folks on here are probably too young to get the reference, so, here's some text from the original boxes:

(Space Quest) Star date: A long, long time ago (sounds familiar, huh?) in a galaxy just around the corner... You are the janitor on the Spaceship Arcada. Your mission! To scrub dirty floors, to replace burned-out light bulbs and to clean out latrines. To boldly go where no man has swept the floor!

(Space Quest 2) Once again, you, Roger Wilco, sanitation engineer and involuntary hero, must don your sanitary space mittens and prepare for the onslaught of evil that Vohal has prepared. A chose not for the queasy or fainthearted. And if you can stomach that... Get ready for the Granddaddy of Gross. The Emperor of Evil. The First Name in Nastiness, Sludge Vohaul himself! With nothing to protect you but your wits and your wet mop, you haven't got a chance!

(Space Quest 4) May the farce be with you! Get ready for a trek through time with everybody's favorite intergalactic sanitation engineer and freelance here, Roger Wilco!

(Space Quest 5) He's lean, he's mean and he's out to clean. Roger Wilcon, the universe's favorite janitor, has bamboozled his way through the StarCon Space Academy and taken command of his own starship. Granted she's only a beat-up garbage scow, but hey, it beats sleeping in the broom closet. ... It's up to Roger to save the universe from the mutant menace, hart his nemesis Captain Quirk, and woo the woman of his dreams or he'll be - Gone with the Trash!

(Space Quest 6) In space, no one can hear you clean! Fight grime and battle evil adversaries with Roger Wilco, janitor turned space adventurer, as he joins forces with video games, TV and sci-fi movies, past and present

Re:Something doesn't seem to add up

[Kjella]

Your imagined point of equilibrium is the point where there's nothing but space garbage, and if you shoot up more there'll be more garbage even though some of it falls back. I'm sure you remember Newton's law of conservation of momentum, now apply it to two oribiting satellites on almost similar trajectories crashing into each other, breaking into many pieces. Basicly, they'd become a spray of junk, some going up, some down, some faster, some slower. They'll spread out as if you fired a shotgun, catching up to some satellites while slowing down covering a greater and greater area to collide with others which will again behave the same way. It doesn't matter if 90 of 100 bits fall to earth if they take out >1,1 satellite each on average. It'll just escalate exponentially like a nuke going off, leaving a fine layer of bullets all over the stable orbit.