Space Sails Could Bring Used Rockets Back To Earth

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."

Comments

And the old junk?

[JorDan Clock]

This might be helpful for rockets launched in 4 or 5 years (Which I think is a very generous estimate on how long something like this would take to be adopted even close to universally.) it doesn't address the issue of all the stuff already up there. How long will the majority of the debris in orbit remain? How effective are these sails when they themselves are punctured by debris? It's a great plan for keeping things from getting worse, but as I understand, a lot of things up there that are in danger of causing damage will be up for quite some time.

Re:And the old junk?

[Profane MuthaFucka]

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:And the old junk?

[rcw-home]

Do you know how much of a difference the size of the debris makes?

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.

Hit or Miss or Hit

[DynaSoar]

"For the final stage of an Ariane 5 launcher, the conical sail would need to have an area of about 350 square metres and be supported by an inflatable mast 12 metres long."

And the expected time to reentry is 25 years.

Good luck on keeping something inflated in space for 25 years. And that's not even considering the probability that the the mast, and the much higher probability that the large sail, will be hit by orbiting debris during that time and torn to shreds

Re:Moon or obiting junkyard

[Rakishi]

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.

Bad idea

[bigsteve@dstc]

If you blow up an old booster ... or satellite ... you only make the space junk problem worse. Instead of 1 large lump of junk that is easy to track and (with luck) avoid, you end up with thousands of smaller lumps, each of which would damage or destroy a satellite.

Making solar sails

[Kim0]

Here is my idea for making an extra light solar sail:

http://kim.oyhus.no/Solar_sail.html

Kim0