Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Szabo on 07/05/2009 03:30:03
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Szabo asked the Naked Scientists:
Hi
I'm quite new at "The Naked Scientist". I like your web side and enjoy especially the podcast (http://www.thenakedscientists.com/HTML/podcasts/), since in Switzerland the terrestrial radio reception of BBC broadcast is not really working.
My Question:
Why do we use rocket to leave the planet?
Using rockets does not look like easy nor is it cheap. And it is not that secure and reliable like aviation. On internet I only find things like "Rockwell X-30" or "Scramjet" but no real alternative solutions. Do you know more about it?
Kind Regards
Gyuri
What do you think?
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Aeroplanes burn a fuel-air mixture; the air comes from the atmosphere; in space there is no atmosphere. So to get propulsion in space, we must carry both components of the combustion reaction with the vehicle. Rockets are the present most simple way to do that.
Burt Rutan has developed a method that uses a combination (http://www.msnbc.msn.com/id/6115258/) where a rocket is carried to a high altitude then released to carry a payload into space. It does not yet achieve orbital velocity.
LONDON - British entrepreneur Richard Branson said Monday that his company plans to launch commercial space flights over the next few years.
Branson’s Virgin transport, entertainment and communications group has signed an agreement with pioneering aviation designer Burt Rutan to build an aircraft based on Rutan’s SpaceShipOne vessel, Branson said.
SpaceShipOne cracked the barrier to manned commercial space flight in June by flying 328,491 feet, or about 62 miles, above Earth — about 400 feet above the distance scientists widely consider to be the boundary of space. The flight lasted 90 minutes.
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Aircraft also use the atmosphere to produce lift as it flows over the surface of the wing. The higher you go the thinner the atmosphere gets so the faster you need to travel. However sooner or later if you want to get higher still, you have no choice but to use a rocket.
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Have a look at:
http://en.wikipedia.org/wiki/Space_elevator (http://en.wikipedia.org/wiki/Space_elevator)
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If not how could we launch the satellite.... It is difficuilt to send like that
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You can also get into space by accelerating your vehicle with a magnetic rail gun but the problem with this is that you have to pass thru the lower atmosphere at escape velocity which wastes a great deal of energy but it would work well on planets that have little or no atmosphere.
See http://en.wikipedia.org/wiki/Railgun
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Hi Naked Scientists!
this is my first post here. i was reading about space elivaters and came across this thread. ;)
i have a question about why we need rockets to get to space. part of it has been answered already on NSF.
http://www.thenakedscientists.com/HTML/content/latest-questions/question/2030/ (http://www.thenakedscientists.com/HTML/content/latest-questions/question/2030/)
So ... would it be possible to attach multiple balloons to a payload or rocket? so it floats as high as it could go and then blasts off.....
or perhaps a new kind of balloon is invented that can withstand the pressure of space and float into space....
or invent a 360 degree donut shaped balloon that has a rocket device inside the balloon.... (imagine a vacuumed rapped rocket) so that when eventually the balloon bursts the rocket ship blasts the short distance left...or blasts though the balloon and beyond.....
have i been watching too much sci-fi? (way too much) but does anyone think this is remotely possible... you would need a very big strong balloon....
well i hope i get some response to my thoughts. ;) its a little outlandish...
cheers
lazykite [;D]
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Lazykite
Kinda like this?
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Google 'Rockoon' - it's a portmanteau of rocket and balloon. Or look here (http://en.wikipedia.org/wiki/Rockoon)
Matthew
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"The first balloon rose properly to 70,000 ft., but the rocket hanging under it did not fire. The second Rockoon behaved in the same maddening way. On the theory that extreme cold at high altitude might have stopped the clockwork supposed to ignite the rockets, Van Allen heated cans of orange juice, snuggled them into the third Rockoon's gondola, and wrapped the whole business in insulation. The rocket fired."
well...there we are.....
but its pretty old and forgotten about...
bring back the "manned Rockoon" i say! would save a ton of $$$$$ to get people into space.
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THE ROCKAIRE!!
If balloons were so useful in stretching rocket performance, why not try high-altitude aircraft? Thus, the "rockaire" concept was born. Actually the rockaire concept was first suggested by Hermann Oberth in his 1929 classic Wege zur Raumschiffahrt. The Air Force studied the idea on and off from 1947 on. The Navy did the same and finally tried the idea out on August 16, 1955, using a Navy F2H2 aircraft off Wallops Island. An altitude of 54 864 m (180 000 ft) was reached with a 69.9-mm (2.75-in.) folded-fin aerial rocket (FFAR) of Korean vintage.42 The Air Force launched theirs in 1956.43 In general, however, the rockaire concept never achieved the popularity of the rockoon. Apparently no important scientific rocket [28] research was carried out with rockaires, in contrast to the hundreds of rockoons fired during the 1950s.
the answer lies hidden in nasa history, long forgotten about!! surely this would save fuel and would mean small rockets could get the same or more people into space or another space station....
(warning, i am not a trained scientist)
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The purpose of a rocket is to provide a self-contained unit which produces a force. And to accelerate a body one requires a force. The rocket engine does not require air from external sources because it sources are internal. Some systems use a first stage which uses a jet propoelled engine whereupon the jet sectgion is ejected and the rocket engine kicks in.
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Why not -
build a rather large "ski-jump" instead?
We could accelerate a spacecraft in a horizontal tube (significantly evacuated of course) by a linear induction motor, then run it up the side of a large mountain to get as high as possible before it exited the tube.
Could this reduce the amount of fuel the rocket needs to carry?
(I'm assuming the speed on exit from the tube would be several thousand MPH.)
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Why not -
build a rather large "ski-jump" instead?
We could accelerate a spacecraft in a horizontal tube (significantly evacuated of course) by a linear induction motor, then run it up the side of a large mountain to get as high as possible before it exited the tube.
Could this reduce the amount of fuel the rocket needs to carry?
(I'm assuming the speed on exit from the tube would be several thousand MPH.)
There are lots of ways to get itno space. Rockets seem to be the most efficient means by modern technology to day. I have a paper on different methods of interstellar travel. I'll fig it up and report its findings.
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...why not try high-altitude aircraft?
Hmm... thought I'd already posted this, but have a read about the Pegasus rocket at:
http://en.wikipedia.org/wiki/Pegasus_(rocket) (http://en.wikipedia.org/wiki/Pegasus_(rocket))