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The Space Garbage Scow, ala Cringely
An anonymous reader writes "Robert X. Cringely once again educates and amuses with his take on how we could clean up the garbage that's in orbit around Earth. I cannot vouch for his math, but it makes sense to me. Quoting: 'We’d start in a high orbit, above the space junk, because we could trade that altitude for speed as needed, simply by flying lower, trading potential energy for kinetic. Dragging the net behind a little unmanned spacecraft, my idea would be to go past each piece of junk in such a way that it not only lodges permanently in the net, but that doing so adds kinetic energy (hitting at shallow angles to essentially tack like a sailboat off the debris). But wait, there’s more! You not only have to try to get energy from each encounter, it helps if — like in a game of billiards or pool — each encounter results in an effective ricochet sending the net in the proper trajectory for its next encounter. Rinse and repeat 18,000 times.'"
That this doesn't break up any debris into more parts - or cause the "net" to break and provide additional pieces of junk circling the earth.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
I thought they were just in the early stages of establishing a ring-world, in terrestrial orbit. Oh well...
There will of course, be no such mission, headed by NASA, or any other fraction of the Federal United States. That banana republic operates on such a scale, only when there is substantial room for contractor and supplier rip-off. If Cringeley can figure a way for DynaCor to pocket a billion on the side, instead of increasing fuel efficiency in spaceflight? It'd happen next year.
"Speaking the Truth in times of universal deceit is a revolutionary act." -- George Orwell
Perhaps Cringely doesn't have a clear idea what sort of debris we are dealing with here
There are, certainly, some big chunks out there; but unpleasant enough(and far more numerous) are the little flecks of paint, bolts, and general fragments of this and that zipping around at bulletesque velocities.
Either this "net" will be made of very close-woven unobtanium, of the sort that we don't yet have, despite decades of interest in the personnel armor industry, or it will have to be a vast spongy particle trap, of the sort whose volume would be completely prohibitive for any available launch mechanism.
Soulskill, why are you posting this crap from Cringely? Any article attached to that name is automatically shit.
I wish Roland Piquepaille had never died. At least his articles had some scientific basis to them, even if he was hated by many people here. Cringley articles, on the other hand, are bunk from top to bottom.
Only the timescale. "Sooner or later" can be in the decades to centuries range, which is minimally useful for most of us now living.
Does Cringely have some kind of seedy business relationship with Slashdot's parent company?
Software piracy is victimless theft.
That's not a bad idea. The real questions would be how much of a drag force could you create at a given distance? The junk is distributed in a cloud around the planet so encounters with junk could be hundreds of meters? Kilometers? Getting closer would require propellant. The field strength is limited by the amount of power you can generate, which ain't much from solar cells. The end effect is it may be completely infeasible because of scale. I wouldn't know how to work the numbers, but maybe someone else does.
AccountKiller
I'd mod you up if I had points. Apparently Cringely hasn't thought about how valuable a few hundred metric tons of refined materials would be in orbit. Instead he says "Nope, we have to gather the stuff and bring it back to Earth." He fails to realize that _someone_ would certainly pay for access to all of that material. He also fails to realize that a polar orbit intersecting an equatorial orbit will result in a relative velocity of about 10 kilometers per second, which equates to 50 megajoules per kilogram. Carbon nanotubes or not, nothing is going to withstand such a large amount of energy in such a small area, repeatedly, along with whatever centripetal forces are acquired from off-center hits from debris.
A visionary he might be, but a practical engineer he is definitely not.
Though I completely agree with your overall point, I'm curious if you have a citation for this sentence. The plate and pencil are in relative motion, yet apparently the impact drills a hole through the plate without even dulling the pencil? I tried googling for an experiment like this with no luck. Now I'm just trying to figure out what insane combination of high-speed photography and a hypersonic wind tunnel with a "pencil of death" feature would be required for proof...
The notion of capturing energy from objects already in orbit is intriguing - but I doubt that "tacking" is sufficient to explain how this works. Tacking occurs when two fluids are connected by airfoils; moreover, the essence of tacking requires the deflection, or bouncing, of the fluids - not the collection of same.
So, in what way could you approach an object and steal its energy. But before that question, what does it mean to steal energy from these captured items? If the trash ends up a part of the garbage scow's orbital dynamics, then "stealing" energy is moot - unless the trash is ejected into a less energetic orbit, the scow cannot end up with a more energetic orbit - which of course defined the solution. The desired "net" may be an electromagnet on a long wire. The intercept is made with a near miss, such that trash and the scow end up like a double-star, tumbling around a common axis - then the electromagnet is released in a moment when the trash is tumbling counter-orbital, leaving the trash in an inferior (and hopefully terminal) orbit - and the scow in a new trajectory of choice - based largely on the intercept angle (to establish the tumble plane) and the release timing to select the angular acceleration.