[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: starship-design: Genuine STR question



Use mass as a flywheel. Spin it up to store energy, brake to extract. Using
micro-G to your advantage, axles and couplings will not be necessary except
during actual spin-up or spin-down operations. Hence, no losses from
friction during "storage".
Energy to compensate for micro-gravitational or vapor-pressure damping  will
be so low as to be suppliable from "compact" sources. A few units of
non-critical thorium heaters could take care of that,. and maybe other
energy necessities. Such heaters already exist and are quite compact, coming
in mettalic tubular units about 7 feet high and 2 feet wide. The heat output
is used to drive turbines. From there on...

Antonio C T Rocha

-----Mensagem original-----
De: Steve VanDevender <stevev@efn.org>
Para: starship-design <starship-design@lists.uoregon.edu>
Data: Domingo, 28 de Fevereiro de 1999 02:14
Assunto: Re: starship-design: Genuine STR question


>Johnny Thunderbird writes:
> > right --- you didn't speak to the issue of decoupling the drive system
> > from the energy production system. I went to some length to stick a
> > battery in the ship with the potential to power the entire journey,
> > just to point up you can make an interstellar journey on stored energy
> > alone. No fusion reaction, no antimatter reaction, no coal, just passive
> > reaction mass which is not fuel, pushed out by stored energy. I don't
> > like a drive without a reaction, but it makes the point a feline can be
> > flayed more than one way, to widen perspective on the way things
> > have to be.
>
>Just how would you store all that energy?  The best way to store
>energy using the least excess mass that I know of is to store it
>as equal parts of matter and antimatter.  Energy in a battery
>_is_ mass.

Use mass as a flywheel. Spin it up to store energy, brake to extract. Using
micro-G to your advantage, axles and couplings will not be necessary except
during actual spin-up or spin-down operations. Hence, no losses from
friction during "storage".
Energy to compensate for micro-gravitational damping  will be so low as to
be suppliable from "compact" sources. A few units of non-critical thorium
heaters could take care of that,. and maybe other energy necessities. Such
heaters already exist and are quite compact, coming in mettalic tubular
units about 7 feet high and 2 feet wide. The heat output is used to drive
turbines. From there on...

>
>And remember, to get something up to something like 80-90% of c
>with an acceleration that passengers and other normal matter can
>stand requires approximately _4 times_ as much fuel mass as
>payload in the ideal case of using antimatter fuel; it goes
>rapidly downhill from there.  That's a tremendous amount of
>energy.  If you didn't have to worry about gradual acceleration
>then you'd need only the mass-equivalent of excess kinetic
>energy.
>
>This does change significantly if you can send energy to the
>payload for propulsion rather than have it carry its own fuel.
>However, if you can beam power to the ship then you may as well
>just deploy a lightsail to reflect that beam during the boost
>phase, as that turns out to be the most efficient way to use
>those photons to accelerate the ship.  Then you don't even have
>to carry excess reaction mass (and any collector that you use to
>pick up the energy would likely weigh as much as the sail).  Then
>you only have to carry fuel/reaction mass for the deceleration
>phase, although I'm of the opinion that finding a way to harness
>the drag of the interstellar medium would probably save you a lot
>of that work.