Robin van Spaandonk wrote:
I have two questions:
1) How are they going to control direction of flight, and prevent off axis
thrust from spinning the craft?
I always wondered how that would work with the
original Orion concept, but Dyson and others said
they had that under control. With this gadget it
should be easier because the explosive charges
held in place with tape before it is exploded, so
it should hit the center of the target. With the
original Orian, they toss the bomb out and have
it go off at just the right moment, which seems
highly problematic, to say the least. At least
with this thing they hold it in place.
2) Where is the Cf coming from to power it? (I
presume they mean Cf, and not Cu
as indicated on page 12.)
Dunno. This is kind of like all those rockets
people want to make with helium-3.
Personally, I think anyone would have to be insane to sit that close to a
nuclear explosion, let alone a whole series of them.
The simulations and tests show that this would
not be a problem, believe it or not. However, I
would not want to be the first to ride in one.
I think these gadgets would be better for deep
space applications than Earth to orbit. First,
because we do not want to pollution on earth.
Second, because lift off from Earth, if the
explosion misfires, or something goes wrong with
the bomb ejector machine designed by the people
who make Coca-Cola machines (really!) for the
original Orion, you are toast. Whereas if
something goes wrong in deep space, you coast
along for a while, fix the problem and then restart.
I wonder if you could have a sort of hybrid or
half-hot fusion machine, where you position a
standard inertial confinement pellet with strips
of plastic, and then zap it with laser beams
driven by CF. as far as I know, this kind of hot
fusion has not produced more energy out than in,
but if it produced a small explosion with very
rapid ejecta it might be a way to convert CF
electricity into thrust. When I discussed lasers
previously, I had in mind that ordinary water
would be heated to about 1000°C with ordinary CF,
and then heated to around 10,000°C with lasers to
increase momentum per unit mass of propellant
(specific impulse, or ISP -- I believe it is called).
Maybe you could even use the same CF engine for
high thrust takeoff and low thrust, high ISP,
deep space operation. Imagine a CF version of the
Phoebus 2, with 5,000 megawatts output, 250,000
lb thrust. On takeoff it consumes ~200 kg of
water per second, probably along with booster
engines that stay behind on earth. An auxiliary
laser system adds another 100 MW to the output
steam, raising the temperature somewhat. Once it
escapes earth's gravity the main engine throttles
way down, and only 0.2 kg per second passes
through it (10 kg per minute; 14 tons per day),
but the lasers raise the temperature to 10,000°C
which gives it a lot more umph. The generator and
laser gadgets together might weight as much as
the Phoebus 2, producing far less thrust overall, of course.
I realize that other approaches are theoretically
far more efficient, but I do not think any of
them are practical -- or close to practical.
Whereas high temperature CF might be close to
reality, and generators and lasers exist.
Perhaps microwaves or some other method could be
used to heat the steam far beyond the melting
point of the CF device. Whatever device is lightest would be best.
- Jed
