"Ross A. Finlayson" wrote:
> Adrian Tymes wrote:
> > "Ross A. Finlayson" wrote:
> > > How about a rocket that you can carry around and set on the ground,
> > > where it will then launch itself into space. Here I am talking about a
> > > rocket that weighs less than fifty pounds. It would have a
> > > self-contained levelling stand so it could point in the good direction
> > > to achieve orbit. I am thinking it would have a propellant or ion
> > > exhaust. If it was fusion powered, it could escape the plasma into the
> > > launch vesicle, and power itself from the via ramscoop once it hit
> > > velocity. You would have to stand fifty or a hundred meters away.
> > Alternate approach: give it wings sufficient to take off from a
> > commercial airport. Much easier integration into existing aerospace
> > infrastructure that way, even if the wings aren't that useful once in
> > orbit. Even non-fusion-powered plasma might be doable to achieve
> > orbit, since you'd only have to supply a few minutes of power from
> > batteries or capacitors.
> > The challenge here would be making the engine light but powerful enough
> > to deliver > 1 G of thrust. Existing similar engines are designed for,
> > at most, .05 G, though that's mainly because they're envisioned only
> > for use after launch, for hours or days of constant thrust, with an
> > onboard power plant which would be inordinately heavy if providing
> > power for 1 G. I suspect one could get some useful economies of scale
> > as the engine gets more powerful; at worst, though, if one engine gives
> > X newtons of thrust above what it needs to thrust itself (including
> > power source, reaction mass, and structure to hold the engine) at 1 G
> > (or whatever launch acceleration is desired) for the launch period
> > (that is, however long it takes to achieve orbital velocity), and one
> > needs Y newtons of thrust to give the same acceleration over the same
> > period to the rest of the rocket, then one simply needs to mount Y/X
> > engines.
> I was thinking along these lines as well. For example, it could be
> multi-stage rocket or missile, with the lift stage components used as
> reaction mass as its functional apparatus is outmoded. So, the booster to
> low orbit could direction the launch stage component towards the planet.
> The only practical application of this I have is making those cardboard
> rockets with the chemical engines with electric starters, for examples the
> Estes rocket, that launch and have a parachute or glider to return the
> nacelle and body to Earth.
My application: single stage spaceplane, to get people and cargoes to
orbit and back.
> This might be at a technology level different than ours.
If it were, then we would never use it. I'd rather make it with our
technology level - pushing said level if necessary.
> Then after that, maybe, you could have a PC terminal that you could tell to
> follow you and it would float through the air carrying your other stuff.
NASA's already making personal satellites for just this application.
They might be able to have them on the space station within a decade.
> > If this launcher could recharge in orbit (electricity via solar
> > panels, and reaction mass via ramscoop - though this latter one might
> > be too slow for practical use), it could launch with just enough power
> > to get to orbit plus maneuvering, then at the end of its mission,
> > reverse thrust and drop to near 0 velocity relative to Earth, dropping
> > back into the atmosphere without resorting to aerobraking (and thus,
> > without needing the thermal protection that aerobraking to remove
> > orbital velocity requires) except to bleed off the last few hundred
> > kmph once it gets to its landing area (just like airplanes do). Then
> > again, it might be better just to launch it with enough charge and
> > reaction mass to get to orbit and return, thus allowing mission abort
> > at any time (better known as "safety margin").
> There could be wings of sufficiently tensile material that could deploy at
> the point of aerobraking. There could be ornithopters with quite complex and
> liquid surfaces. Some designs of planes that use canards and other exotic
> enhancements, not to mention vectored thrust, are highly manueverable, but to
> have a bird, that is small enough that it could have complex and very close
> analogs of the actual bird's structure. What that leads to is the
> development of systems that model organic behavior accurately.
True, true. But *there* we're getting far beyond our current tech
level, such that we'd have to push it quite a ways. Plasma engines, on
the other hand, are tried and tested technology, just not tested at
very high power yet. Using what already exists is cheaper - and at the
moment, access to space happens to be very expensive; one must get that
to be *much* cheaper before one can stop worrying about cost of space
> I think that's one place where computer simulation offers a lot of
> opportunity. For example, if we wrote just now as we did, and the program
> gave us the design to build it, then we have built a good program.
But how can you know if a newly developed simulation's not overlooking
some critical aspect of reality before you actually do what is
This archive was generated by hypermail 2b30 : Mon May 28 2001 - 09:56:21 MDT