Antimatter rocket v. black hole starship

[Rasalhague]

In http://arxiv.org/abs/0908.1803v1" , 2003, Robert Frisbee offers some ideas on the design of an antimatter rocket. Crane and Westmoreland concentrate more on the possibility of a black hole starship, rather than the size or shape of the craft. I'm wondering, how many of the constraints that influence Frisbee's design would carry over to a black hole starship? In particular, Frisbee's design calls for a long, needle-like craft, much of its length being taken up with a radiation shield (5.15*10⁵ metres) and refrigerator (7.6*10⁴ metres), p. 27. Would a ship powered by Hawking radiation from a subatomic black hole be likely to have have similar requirements?

 

[qraal]

In http://arxiv.org/abs/0908.1803v1" , 2003, Robert Frisbee offers some ideas on the design of an antimatter rocket. Crane and Westmoreland concentrate more on the possibility of a black hole starship, rather than the size or shape of the craft. I'm wondering, how many of the constraints that influence Frisbee's design would carry over to a black hole starship? In particular, Frisbee's design calls for a long, needle-like craft, much of its length being taken up with a radiation shield (5.15*10⁵ metres) and refrigerator (7.6*10⁴ metres), p. 27. Would a ship powered by Hawking radiation from a subatomic black hole be likely to have have similar requirements?

The radiation from a decaying black-hole is likely to be very high energy gamma-rays in the temperature range suggested for the black-hole starship. Thus long and thin is not a bad idea for a starship powered by such an extreme energy source. Crane & Westmoreland's design isn't as developed as Frisbee's (sketchy) antimatter starship designs, but I can make a rough sketch of what it would need. For example a 200,000 ton black hole radiates 9E+15 W - which is an incredible amount of energy to radiate. Oddly enough it's not as impossible as it sounds, just very hard. My best guess is to surround the black hole in a dense plasma of uranium 238, to thermalise the gamma-rays. We want an equilibrium temperature of about 25,000 K, thus a plasma sphere around ~180 metres in radius surrounded by a very high efficiency reflector to direct the resulting UV output. That power output is mind-boggling, but that's "photon rockets" for you.

 

[twofish-quant]

Also one big difference between black hole starships and anti-matter ones is that anti-matter star ships are merely an "engineering problem." We know all of the pieces for an anti-matter starship exist, it's just a matter of putting them together. The trouble with mini-black holes is that we don't know if they exist at all, nor do we know how to make them if they don't exist.