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."
When we've got countries blowing up satellites in orbit, that's far worse than a big booster plodding along in a decaying orbit.
I swear to God...I swear to God! That is NOT how you treat your human!
The universe is mocking us for not thinking ahead. Again.
And our reaction? "Let's make those pieces bigger!"
I wonder if we could operate a remote-controlled Mass Catcher? The one designed for the 1975 Stanford Summer Study would do if you left off the intake grid of cables. It would be a rotating Kevlar cone. Centrifugal force would hold loose regolith in place, which would act to absorb the impact of the intercepted debris. The same rotation would also act as artificial gravity to prevent the escape of secondary splash debris. Using a pellet launcher as a thruster would be safe, since the pellets would be traveling at far above Earth escape velocity.
"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
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
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.
This is not a solar sail, this is aero-braking.