Recovering the Hubble Telescope? (Earth, light, spacecraft, Apollo)
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It'd be great if the Hubble could be recovered for placement in the Smithsonian. I mean, how cool would it be to see the actual telescope and not a mock-up or a twin which is presumably used to practice repairs?
I realize that the Hubble is huge (but only twice as massive as the Command Module from Apollo) and that this would be very expensive and would risk human lives just for the sake of a museum display, but still, this is the very first space-based telescope and seems to deserve a better fate than crashing into our planet or becoming space junk.
While drafting this post, I checked Wikipedia to verify some facts and found that NASA had actually considered this very notion. They proposed and then nixed loading it back into the Shuttle whereas attaching an external propulsion unit for a controlled de-orbiting is still a possibility.
I was wondering if it would be possible to attach a giant chute/sail or balloons to float the Hubble down to a splashdown recovery? This would be to avoid a fiery re-entry.
Why do space objects always go white hot when falling to Earth?
Do the objects reach a terminal velocity so high that by the time it encounters our atmosphere, no matter how thin, the friction causes heating?
If there is enough atmospheric density to cause heating, isn't there enough for manageable drag or lift?
The "hot re-entry" seems to be a very dangerous part of space travel (we lost Columbia this way). Isn't there a way to avoid this and its attendant heat shields and ceramic tiles? Other than using retro rockets, of course, which have their own problems of weight and complexity.
It's a noble idea but I'm sure the expense would be quite bit, better off spent on something that is productive. Perhaps they could just leave it there for a future generation to retrieve.
Quote:
Originally Posted by drunk on kool aid
Why do space objects always go white hot when falling to Earth?
Do the objects reach a terminal velocity so high that by the time it encounters our atmosphere, no matter how thin, the friction causes heating? .
It's the friction and it effects high speed aircraft too. The SR-71 when sitting on the ground leaks fuel, imagine being one of the first guys getting in that plane.. hear is your 2000mph plane, don't mind that big puddle of jet fuel on the ground. LOL
The reason it leaks fuel is because it generates so much heat during flight that the skin of the aircraft expands up to a foot. The panels of the aircraft were loosely fitted together and would seal during flight hence the leaking on the ground. Must have been a technological issue they couldn't overcome back in the 60's. None the less it still remains the fastest manned aircraft to date, at least known publicly. Not bad for 60's technology eh?
The hubble, like all orbiting objects, is travelling at at least 17,500 mph to stay in orbit. It is the speed they are travelling that keeps them in orbit in a type of perpetual freefall. If it were possible to slow the speed of the hubble to zero and a multi step retro rocket/ parachute system was used it would be theoretically possible to bring the hubble back to earth quite gently. It is the slowing down part that costs a lot of money and fuel. When the shuttle wants to return they fire the main engine and slow the craft enough so that gravity overcomes the perpetual freefall of 17,500 mph and the craft simply drops out of orbit, It's still going 15,000 mph which is why when it hits the atmosphere friction heats up the heat shield tiles to over 5000 degrees F. That's why all reentering objects heat up to "white hot", the friction. At temperatures reaching 5000 degrees only tungsten steel will remain solid, all other metals will melt. They can't use tungsten as a material for building a spacecraft as it is far too heavy and brittle to have structural integrity.Even if they did use tungsten as an outer shell the 5000 degree heat would still melt everything else inside the craft. So short answer ....yes it's technically possible to soft land the Hubble. Will they do it?? No way! It would be far too cost prohibitive and not worth the effort for a museum piece!
It'd be great if the Hubble could be recovered for placement in the Smithsonian. I mean, how cool would it be to see the actual telescope and not a mock-up or a twin which is presumably used to practice repairs?
I realize that the Hubble is huge (but only twice as massive as the Command Module from Apollo) and that this would be very expensive and would risk human lives just for the sake of a museum display, but still, this is the very first space-based telescope and seems to deserve a better fate than crashing into our planet or becoming space junk.
While drafting this post, I checked Wikipedia to verify some facts and found that NASA had actually considered this very notion. They proposed and then nixed loading it back into the Shuttle whereas attaching an external propulsion unit for a controlled de-orbiting is still a possibility.
I was wondering if it would be possible to attach a giant chute/sail or balloons to float the Hubble down to a splashdown recovery? This would be to avoid a fiery re-entry.
Why do space objects always go white hot when falling to Earth?
Do the objects reach a terminal velocity so high that by the time it encounters our atmosphere, no matter how thin, the friction causes heating?
If there is enough atmospheric density to cause heating, isn't there enough for manageable drag or lift?
The "hot re-entry" seems to be a very dangerous part of space travel (we lost Columbia this way). Isn't there a way to avoid this and its attendant heat shields and ceramic tiles? Other than using retro rockets, of course, which have their own problems of weight and complexity.
You could try the SpaceShipOne trick and give it some wings and try to redesign it for a feathered reentry. Maybe a lot more difficult but might be able to justify the expense as a type of experiment. In general most folks think the technique will not work at much higher orbits. Depending on how long you could make the reentry last would probably be the key. And then it has to fly at least sort of once in the atmosphere, at least glide like a rock and figure out where to land.
This snip shows how it works.
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Feathered reentry SpaceShipOne in flight
In 2004, aircraft designer Burt Rutan demonstrated the feasibility of a shape changing airfoil for reentry with the suborbital SpaceShipOne. The wings on this craft rotate to provide a shuttlecock effect. Notably, SpaceShipOne does not experience significant thermal loads on reentry.
This increases drag, as the craft is now less streamlined. This results in more atmospheric gas particles hitting the spacecraft at higher altitudes than otherwise. The aircraft thus slows down more in higher atmospheric layers (which is the very key to efficient reentry, see above).
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Demo'ing the ability to return large objects from space would have some value. Returning Hubble might have value in that sense via the shuttle as a learning exercise. Also might have some value to study what happens to a larger object exposed to long periods in space, nothing beats hands on causal access in some hanger. We waste money in so many ways, the shuttle is going there anyway, learn to bring something big back if it is possible within the Shuttle flight envelope.
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Give it wings, try to fly it down.............
