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- Path: sparky!uunet!igor!yosemite!rmartin
- From: rmartin@yosemite.Rational.COM (Bob Martin)
- Newsgroups: sci.space
- Subject: Re: Propulsion questions
- Message-ID: <rmartin.711737055@yosemite>
- Date: 21 Jul 92 16:44:15 GMT
- References: <1992Jul16.154632.15534@wpi.WPI.EDU> <BrHtC3.29y@zoo.toronto.edu> <BrKIJJ.CKH@watdragon.waterloo.edu> <rmartin.711643766@thor> <NICKH.92Jul20115850@VOILA.VENARI.CS.CMU.EDU>
- Sender: news@Rational.COM
- Lines: 50
-
- nickh@CS.CMU.EDU (Nick Haines) writes:
-
- >In article <rmartin.711643766@thor> rmartin@thor.Rational.COM (Bob Martin) writes:
-
- > What about Arthur C. Clarke's A-Drive. Blow a small stream of
- > reaction mass past a mini-black hole (A few tons??, the size of a
- > proton??) Some of the stream is accellerated into the singularity.
- > The frictional heating of its accelleration and accreation is absorbed
- > by the rest of the matter in the stream which then roars out the
- > exhaust nozzle and supplies thrust.
-
- >Problems:
-
- >- if the black hole is small enough to be light (you have to carry it
- > along, you don't want too much mass) it's also small enough to
- > evaporate in a burst of extreme gammas.
-
- clearly you want to make sure that the singularity is massive enough
- such that its evaporation rate is slower than its accretion rate.
- Does anybody know what the relationships of mass to evaporation rate
- is? I was under the impression that explosive evaporation only took
- place when the singularity was very very small, i.e. < 1e6g or so.
-
- >- you still need lots of reaction mass.
-
- You need reaction mass, yes. The amound depends on the delta V you
- need. For short hops, you only need a little. For long hauls, you
- need more. And, if you are thinking about interstellar hops, you can
- still use the bussard ramscoop to collect hydrogen and blow it past
- the singularity.
-
- Can anybody tell us the efficiency of this with respect to a fusion
- drive?
-
- >- it's probably at least as tricky to control as a bottle full of
- > anti-hydrogen.
-
- Maybe. Remember you can control the charge of a singularity just by
- forcing it to swallow some ions. Also, its mass will give it a
- certain amount of inertial stability, i.e. it's not likely to be
- bouncing around its container at a decent fraction of C. Thus, the
- control system will have time to marshal it forces and keep the
- singularity at bey.
-
-
- --
- +---Robert C. Martin---+-RRR---CCC-M-----M-| R.C.M. Consulting |
- | rmartin@rational.com |-R--R-C----M-M-M-M-| C++/C/Unix Engineering |
- | (Uncle Bob.) |-RRR--C----M--M--M-| OOA/OOD/OOP Training |
- +----------------------+-R--R--CCC-M-----M-| Product Design & Devel. |
-