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Fusion Thrusters For Space Travel
kgeiger writes "John J. Chapman, a physicist and electronics engineer at NASA's Langley Research Center, envisions a laser-pumped fusion drive. Chapman estimates the drive can produce thrust 40 times more efficiently than existing ion engines such as those on the Dawn mission now exploring the asteroid belt."
The reaction is
1H + 11B -> 12C -> 4He + 8Be -> 4He + 4He + 4He
so there are more output nuclei than input.
However, I suppose it is true that all of the energy is coming from fusion, as 12C -> 4He + 4He + 4He is exothermic. (The reverse reaction is an energy source for stars under some circumstances.)
12C is normally stable, so for this reaction to go as stated the nucleus must be created in some suitable excited state.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
1. Spacex's rockets were based on a concept engine called Fastrac, killed in 2001. Spacex have scaled up the thrust by a factor of four and the ISP from 260 seconds to 300.
2. Spacex's aluminium-lithium friction stir welded tanks were developed by LockMart for the SLWT first flown by the space shuttle in 1998. X-33 used experimental composite tanks and ignored the lighter FSW technology because it wasn't "Space Age" enough. This is why X-33 failed.
3. Transhab was not killed by the 1996 congress. Transhab didn't exist in 1996. Transhab was killed by House Resolution 1654 in 2000 to prevent NASA from even thinking about Mars. If NASA had called it an Orbhab instead of a Transhab then it wouldn't have been killed.
4. Nope.
5. VASIMR barely existed on paper in 1996. It didn't exist as a national program and there was nothing for congress to kill.