Returning space dust to Earth
Discussion
http://news.bbc.co.uk/1/hi/sci/tech/4467676.stm
I have a question.
The yanks a couple of years ago collected some material and then sent it back to the earth where the parachutes failed and it slammed into the earth at 500mph, and were left sifting cosmic material from sand.
The japs are now doing something simliar but with asteroid dust.
But why not just deliver the payload to the International Space Station and bring it down with say the next shuttle (or at least a manned flight)?
I mean - you go to all this trouble and expense - so why not deliver the final package via a safe method for the final leg?
I have a question.
The yanks a couple of years ago collected some material and then sent it back to the earth where the parachutes failed and it slammed into the earth at 500mph, and were left sifting cosmic material from sand.
The japs are now doing something simliar but with asteroid dust.
But why not just deliver the payload to the International Space Station and bring it down with say the next shuttle (or at least a manned flight)?
I mean - you go to all this trouble and expense - so why not deliver the final package via a safe method for the final leg?
Having the sample vehicle re-enter the atmosphere,
deploy a parachute and then recovering the whole
thing mid-air would be a walk in the park compared
to trying to have the thing return from deep space
and try and precisely match orbit, speed and location
with the ISS - it would require an *astounding* amount
of manouevering fuel.
deploy a parachute and then recovering the whole
thing mid-air would be a walk in the park compared
to trying to have the thing return from deep space
and try and precisely match orbit, speed and location
with the ISS - it would require an *astounding* amount
of manouevering fuel.
eharding said:
Having the sample vehicle re-enter the atmosphere,
deploy a parachute and then recovering the whole
thing mid-air would be a walk in the park compared
to trying to have the thing return from deep space
and try and precisely match orbit, speed and location
with the ISS - it would require an *astounding* amount
of manouevering fuel.
Exactly. To re-enter the earth's atmosphere the capsule uses the atmosphere as a brake. To enter orbit with the Space Station the capsule would need to use retro rockets in space to brake from thirty or forty thousand miles and hour, and then manouver to dock. The capsule would need to have a huge amount of fuel on board.
Edited for some appalling typos.
>> Edited by alexkp on Monday 28th November 08:10
ultimasimon said:
Ever so slightly off topic..
Does anyone remember 'Space Dust' the sweet? You know the one in a packet which you used to pour in your mouth and then it explodes like mini-popcorn. I liked that
Wonder if you can still buy it now
theres the 'spaceships' or 'saucers' I think, but not sure,
I'm an after eight man myself, and so's my wife!
...and the later uprated weapons-grade version of Space Dust, 'Pop Rocks'. Same idea, bigger chunks of pressurised CO2-filled sweetie. Exploded in your gob with such violence that it bloody hurt at times. Aforementioned coke-assisted in-gob detonation once demonstrated on the Adam & Joe Show...
Previous posters are correct with the returning-to-Earth-and-slowing-down problem. Returning Apollo spacecraft boosted out of lunar orbit and then coasted towards Earth. When they reached the point when the gravitational pull of the Earth and Moon were equal (La Grange point? Can't remember...) the spacecraft was down to 'only' 3000 mph. Accelerated once the Earth's pull took over and reached 25000 mph at entry interface through nothing other than gravitational acceleration. Some of these blokes hold the World absolute human speed record on returning lunar flights. The fact that the command module went from 25000 mph to zero floating on the ocean in something like 20 minutes I still find astounding.
ST
Previous posters are correct with the returning-to-Earth-and-slowing-down problem. Returning Apollo spacecraft boosted out of lunar orbit and then coasted towards Earth. When they reached the point when the gravitational pull of the Earth and Moon were equal (La Grange point? Can't remember...) the spacecraft was down to 'only' 3000 mph. Accelerated once the Earth's pull took over and reached 25000 mph at entry interface through nothing other than gravitational acceleration. Some of these blokes hold the World absolute human speed record on returning lunar flights. The fact that the command module went from 25000 mph to zero floating on the ocean in something like 20 minutes I still find astounding.
ST
I think there might be a problem with docking with the ISS because of its orbit, synchronising to that orbit would require a lot of energy if your travelling at thousands of miles per hour (would require an heavier/more expensive to launch satellite because of extra fuel). It could also endanger the station should anything go wrong, maybe the people on board the ISS would need to have control of the satellite to make sure it doesnt crash into them 
In other words it would be more expensive and dangerous to dock with the ISS.
>> Edited by scorp on Monday 28th November 09:07
In other words it would be more expensive and dangerous to dock with the ISS.
>> Edited by scorp on Monday 28th November 09:07
It depends on where the "collecting" space probe was "parked" in space whilst doing its collecting. If it was already in an orbit compatible with the ISS, then it might be technically feasible to rendevous and retrieve the probe using the ISS. However, even that would place a load of weight, complexity and cost onto the probe - it would have to carry manoeuvering rockets and fuel plus rendevous equipment (transponders, radar) plus control systems to allow it to be operated by remote control from earth plus extra manpower to do all these things. Most pure scientific missions of this sort struggle to raise funds and control their costs. Trying to incorporate all this extra "stuff" to perhaps facilitate retrievel would make the project prohibitively expensive.
All the above factors would be multiplied by a huge amount if the probe had been in a solar orbit (say) rather than an earth orbit.
All the above factors would be multiplied by a huge amount if the probe had been in a solar orbit (say) rather than an earth orbit.
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