Space Sails Could Bring Used Rockets Back To Earth 76
GordonCopestake writes "An article from New Scientist proposes that all new spacecraft have sails attached to bring them back to earth — a measure that would reduce the amount of garbage in space. From the article: 'The risk to spacecraft from a collision with space debris could be reduced by equipping launchers with a gossamer-thin "sail." The idea is to deploy the sail after the rocket has released its payload to amplify the drag of the last vestiges of the atmosphere, and so force the rocket out of orbit.'"
Wired has a related story about the risks faced by the space shuttles as they share orbits with tons of drifting space debris. "... in the 54 missions from STS-50 through STS-114, space junk and meteoroids hit shuttle windows 1,634 times necessitating 92 window replacements. In addition, the shuttle's radiator was hit 317 times, actually causing holes in the radiator's facesheet 53 times."
Comment removed (Score:3, Informative)
Re:And the old junk? (Score:5, Informative)
The debris in low orbits where the Shuttle operates will return within just a few years. Higher than that means it stays up longer.
If an object is orbiting twice as high as the shuttle, about 500 miles, it'll stay up roughly a couple centuries. Just a bit higher than that and you're measuring orbital lifetimes in millennia.
Re:Woah (Score:3, Informative)
Re:Moon or obiting junkyard (Score:5, Informative)
Space is not earth.
Moving things in space and keeping them from crashing into the atmosphere requires energy. Energy means fuel and fuel means you need to pay to send it up. Docking objects in space requires complex electronics which means even more mass to send up.
Recycling requires a highly advanced and complex industrial base which doesn't exist in space. If it did then you wouldn't need the junk since you can mine your own raw materials.
Re:And the old junk? (Score:3, Informative)
The debris in low orbits where the Shuttle operates will return within just a few years. Higher than that means it stays up longer.
Do you know how much of a difference the size of the debris makes? The wikipedia orbital debris entry [wikipedia.org] doesn't say.
---
Don't be a programmer-bureaucrat; someone who substitutes marketing buzzwords and software bloat for verifiable improvements.
Re:Shoot em up? (Score:3, Informative)
Re:And the old junk? (Score:5, Informative)
Densities of materials vary widely, but as a rule of thumb, mass increases with the cube of an object's size, but drag only increases with the square.
Re:Getting bombarded by our own crap (Score:2, Informative)
We are the tubgirl of Sol system.
Re:And the old junk? (Score:3, Informative)
It depends tremendously on the orbit and the object. Some 'objects', like dumped urine or water, submlimate. They're still deadly if they hit you from even a slightly different orbit, since we're talking about base speeds of roughly 18,000 mph in low earth orbit: it's the difference between the orbits that determines their relative velocity, and that's easily as much as 10%. (Head-on collisions are basically unheard of: one object would have to be orbiting the other way entirely, and no one does that due to the launch costs of orbiting against the Earth's spin.)
Small objects in low orbits are also subject to normal orbital decay, from the extremely thin atmosphere and very slight gaseous content of ordinary space, which is very thin but very real. Even solar wind can help decay orbits, by providing a consistent though slight thrust in a direction at an angle to that orbit, and depleting the orbit of its angular components. (Tidal effects are not noticeable factors on an object _that_ small.)
Geosynchronous orbits are a whole separate problem: they last much, much, much longer, and that orbital space is getting crowded by junk.