Why does the shuttle have to pick up the station's garbage?

[CalliArcale]

Maybe he means an inflatable ballute? That concept has certainly been floating for aerobraking. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[chriscdc]

That's why I said foil not mylar. It has some structural rigidity.<br />You make it into a pretty shape before you let it go.<br />My brain can occasionally (very occasionally) work.

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>Shuttle_guy, question for you: could the Shuttle decrease its speed and reenter with a lower heat loading if it skips in and out of the atmosphere in a succession of parabolas?<p><hr /></p></p></blockquote><br /><br />Actually, you can reduce heat loading this way, but it's very very very very risky. The Soviets attempted it several times with their Zond spacecraft. The Zonds were basically stripped-down Soyuz spacecraft; if successful, they would've been used to put Soviet cosmonauts on circumlunar trajectories, using Proton rockets for the initial boost, and leaving behind the bulky orbital module to save weight. There is a problem with this strategy, however: Soyuz doesn't have a thick enough heat shield to endure an Apollo-like reentry. It had to reenter faster (so the duration of heating was shorter), but this would subject the crew to hazardous or even lethal G-forces. So what they did was they attempted a tricky double-skip reentry to bleed off speed without burning all the way through the heat shield. It wasn't a 100% success. Most didn't even make it to orbit, but of those that attempted the double-skip, one failed and was self-destructed, one failed to make the second skip but was still recovered after a 20G ballistic reentry (unacceptable for humans), and then Zond 6 managed to acheive the double-skip correctly. The mission was not a complete success; the spacecraft had depressurized. Zond 7 later achieved complete mission success in August 1969, followed by Zond 8 14 months later. So three Zonds acheived a double-skip reentry, although one of those would've killed its crew due to an unrelated failure.<br /><br />For trash, though, I think it kinda defeats the purpose to do a multiple-skip entry. You want to get the stuff firmly out of orbit promptly enough that you don't have to worry about something failing and the junk staying where it can do some harm.<br /><br />BTW, a major reason why the Shuttle <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[halman]

chriscdc,<br /><br />A great deal of trouble is gone to putting things in orbit, because that means getting the object moving at 5 miles per second relative to the surface of the planet. That energy has to be dissapated in some way to leave orbit, which is usually done by changing the orbit enough that the object enters the upper atmosphere at an angle which will result in the object slowing down gradually. Canceling the entire 5 mps of velocity would take the same amount of propellant needed to acheive orbit. Merely slowing an object down relative to the International Space Station would not neccessarily result in it entering the atmosphere, which means that the object is at risk of hitting another object in a different orbit.<br /><br />Only by using a velocity change which is carefully calculated to result in intercepting the atmosphere can an object be de-orbited, and the velocity change needs to result in a rapid interception of the atmosphere to avoid turning it into a dangerous projectile.<br /><br />By the way, recycling water is a very difficult proposition, without a living organism to remove the wastes. The ISS uses waste water to produce oxygen, with the Elektron system. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>