Laser driven acceleration of fuel

Today in Physorg.web
http://www.physorg.com/news10433.html
it was reported that laser driven accleration of carbon achieved 3.6
MeV/nucleon in an amazing 10 micron distance and that they could
achieve fairly high beam currents. They accelerated C atoms to 36 MeV.
This could be used to acclerate fuel beams to long distance space craft
so that the spacecraft did not have to carry its fuel. The energy to
accelerate the fuel could be produced in a close solar orbit beaming
the fuel beam to the craft that would catch it and then use it as
reaction mass. This would mean the spacecraft would not have to carry
its fuel so the engines would need less thrust. Of course, the fuel
beam velocity would have to be matched reasonably well to the speed of
the spacecraft at any time but that should not be very difficult. With
this system, an ion driven craft could have fairly small engines and
still achieve a significant fraction of the speed of light.

sounds interesting, but not too feasible. at longer distances the aiming
system for such a thing will go into fits, and efficiency goes down the
tubes.

I'm not saying you shouldn't try to build a prototype of it, which would be
more progress than posting someone else's article about it


wrote in message
ups.com...
Today in Physorg.web
http://www.physorg.com/news10433.html
it was reported that laser driven accleration of carbon achieved 3.6
MeV/nucleon in an amazing 10 micron distance and that they could
achieve fairly high beam currents. They accelerated C atoms to 36 MeV.
This could be used to acclerate fuel beams to long distance space craft
so that the spacecraft did not have to carry its fuel. The energy to
accelerate the fuel could be produced in a close solar orbit beaming
the fuel beam to the craft that would catch it and then use it as
reaction mass. This would mean the spacecraft would not have to carry
its fuel so the engines would need less thrust. Of course, the fuel
beam velocity would have to be matched reasonably well to the speed of
the spacecraft at any time but that should not be very difficult. With
this system, an ion driven craft could have fairly small engines and
still achieve a significant fraction of the speed of light.

Sorry about that post, I wasnt thinking. If you could make such a
beam, it would be better simply to use the beam directly to accelerate
the spacecraft.

wrote:
Sorry about that post, I wasnt thinking. If you could make such a
beam, it would be better simply to use the beam directly to accelerate
the spacecraft.

There was a proposal to use a laser to flash convert the surface of a
block of ice to steam to power a rocket. The ice would contain "dirt"
so that it would be dark coloured. This means that it would absorb the
laser light. I am not sure what kind of ISP were achievable. However,
it means that chemical energy of the fuel is no longer the limiting
factor.