Ground-powered Rocket? Conductive Contrail?
sanman
Another silly idea I'd like to ask about -- could a channel of ionized
gas be used to feed electric current from a ground station to power a
rocket ascending to orbit?
I've read about femtosecond-pulse lasers being used to create
persistent conductive channels through the air. They have been used to
make instant "virtual lightning rods" to divert lightning bolts away
from skyscrapers or airports, when a storm appears.
If the tremendous electrical power of a lightning bolt can be conveyed
down such
an ionized channel from the sky to the ground, then why can't
electricity be conveyed up it to reach a rocket travelling upwards?
As we just covered before, the atmosphere only extends up a couple of
dozen miles, but could one perhaps use a rocket's exhaust contrail to
create a conductive/ionized channel along it? You could then feed
current from your ground-based power station up that conductive
channel. (LOL, would sort of give new meaning to the phrase
"Fly-by-wire"!)
You'd need to keep your conductive exhaust contrail from
dispersing/dissipating, so you'd be hostage to
wind/weather/localized-turbulence on the way up. Perhaps you'd use
Doppler Radar to help you pick the right time and place for good
launch conditions. But if it only takes about 8 minutes for the
Shuttle to reach orbit, then using that as a guide, perhaps that's a
reasonable window for the exhaust contrail to remain cohesive. And if
it's not a manned payload, perhaps you'd have higher acceleration and
even quicker travel time to orbit.
(Hmm, I guess they don't have many hydroelectric dams in the Mojave
Desert, so you'd have to build a nuclear reactor out there. Or perhaps
a mobile rolling nuclear reactor? Or a ship-borne one, if you're
launching out at sea?)
Would you absolutely need the laser to make the exhaust contrail
conductive? It would help, but then you're going to need the exhaust
contrail to be in a straight line. Perhaps one could select exhaust
gas(es) that would facilitate the conductivity and also favor staying
cohesive? If your conductive contrail could work all by itself without
any ionizing laser to aim, the nice thing about it is that your
current would just "follow the trail" and always make it to the
target.
We know that exhaust contrails are often so visible in the sky because
the exhaust gases condense into little ice crystals in the cold of the
upper atmosphere. I don't know if this would be a good thing or a bad
thing. The frozen crystals might fall more quickly, but they'd only
appear in the atmospheric portion of the contrail, which is vertical
anyway, so hopefully falling wouldn't distort the contrail shape too
much. Maybe the passage of enough current would keep the contrail hot,
and prevent condensation/freezing.
What about a particle beam of accelerated ions? Could that be used as
a channel for electric current to travel up, instead of the exhaust
contrail? I know people have suggested microwave beaming, but they
would be a lot more dangerous to a crew/cargo than electric current,
IMHO.
So what do you think of these approaches? Has anybody ever suggested
any of this
before? What are the shortcomings and difficulties?
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Don Kelly
"sanman" <mano...@yahoo.com> wrote in message
news:cmr1r7$9k4r$1...@saturn.cs.uml.edu...
Where is the return path for the current? Secondly, if you have this, what
power can be handled for long enough to do any good.? What energy is lost
in the conductive channel?
Note that while the peak power in a lightning stroke is large, it is mainly
dissipated in the conductive channel. If that occurred- not much energy
would be left to power the rocket. (note a lightning stroke transfers a lot
less energy than most think- maybe enough to run a 100 watt bulb for
100hours -worked it out once and came out with an even lower figure)
--
Don Kelly
dh...@peeshaw.ca
remove the urine to answer
Damon Hill
mano...@yahoo.com (sanman) wrote in
news:cmr1r7$9k4r$1...@saturn.cs.uml.edu:
>
> Another silly idea I'd like to ask about -- could a channel of ionized
> gas be used to feed electric current from a ground station to power a
> rocket ascending to orbit?
What's the return path going to be? Electricity flows in a
circle. What's the electricity going to power?
I think it'd be a lot simpler to use the laser to heat a
reaction mass carried by the rocket; it's been experimentally
demonstrated.
--Damon
Fred McGalliard
> gas be used to feed electric current from a ground station to power a
> rocket ascending to orbit?
Yes, and no. You can open a channel, at some considerable energy
expenditure, but if you pass a current up it, the magnetic field and plasma
pressure tend to kink the path. This looks like the classic linear
discharges, THX I think is one of the fusion experiments using this. The
current produces a field and pinches the plasma. The increasing plasma
pressure tries to stretch it out along the path. Like pushing on a string it
ropes up and twists over itself in fractions of a millisecond. I have never
seen a process that would maintain a steady balanced current, even like the
stellerator where you get to control the magnetic field around the
discharge.
I did like the laser driven air ram. It was designed to focus a received
beam from the rear into a ring style ram jet, heating the air and driving
the ship upward. Neat stunt, and I think demonstrated in the few KW level.
This ship would take several hundred megawatts I think. Big big laser
system, pointed to a small and rapidly retreating object through a badly
distorted air. A related idea would use a space born beam to provide the
energy for a steam rocket operated above most of the atmosphere. Some of
this stuff might work very well for things like material resupply and the
like.