shuttle to the moon?

[cjameshuff]

Another major issue with NSWRs is propellant storage. This isn't stuff you want puddling up under a leaking tank. Especially when you consider that you're a walking neutron reflector.

A while back I came up with a potential way to use fusion in a NSWR...the Antimatter-Catalyzed Fusion-Boosted Nuclear Saltwater Rocket, or ACFBNSWR. Not only would the fusion contribute directly, with fusion as a source of neutrons your fissile saltwater doesn't need to be as highly enriched, and in fact needn't be capable of sustaining a reaction on its own...better safety through antimatter!

As for fission fragment engines, they would only spend a small fraction of their operational lifetimes in Earth's vicinity even if not initially boosted away from Earth on chemical rockets to avoid a slow outward spiral. Away from Earth, apart from being diluted to the point where you'd be lucky to ever encounter a single fragment, I don't see why they would stick around when the charged particles of the solar wind don't. In a perfect vacuum they might be trapped by the sun's magnetic field (the gyroradius is around 47000 km in the area of Earth's solar orbit, if I crunched the numbers right), but I suspect they'd instead flow outward with the solar wind, possibly with their trajectories curling around approximately that radius until they're headed outward with the wind. I'm no plasma physicist though.

[ka9q]

You're probably right that they would join the solar wind. They would probably eventually run into the heliopause being explored by Voyager 1 right now. I do wonder where those particles go when they're stopped by the interstellar magnetic field.

The earth (and other planets with magnetic fields) have magnetospheres compressed into teardrop shapes by the solar wind, so I suppose the magnetosphere of the sun is shaped similarly by the interstellar wind. Maybe charged particles do eventually escape the solar system by moving into the tail.

[ipearse]

Here's a film of Orion subscale tests done in the late '50s.  If you want to cut to the chase, go to the 9-minute mark.

Amazing. I'd heard about Project Orion before but not see those videos. The shape of that test article makes me think of From the Earth to the Moon and the capsule being fired out of an enormous cannon. I remember the BIS and their Project Deadalus as a development of that (Project Orion) idea.

Edited for typo.

[raven]

Project Longshot was a similar idea to Daedalus, only it was intended to go into orbit as opposed to a flyby and used a separate reactor for power.
How close would antimatter catalysed nuclear pulse propulsion be?

[cjameshuff]

How close would antimatter catalysed nuclear pulse propulsion be?

I don't think we can really say. It could mass considerably less than a reactor, pulsed power supplies, and particle beam or laser arrays to initiate fusion...or it could conceivably mass more in ultra-failsafe magnetic suspension systems. It might influence the design in other ways...a continuous fusion system might be better, since you don't need to charge up pulsed power systems for discrete shots...inject antimatter beams into a continuous stream of fusion fuel/propellant.

[Glom]

How does antimatter catalyse the reaction?

[cjameshuff]

How does antimatter catalyse the reaction?

It's technically a misnomer. A small amount of antimatter is used to provide the heating needed to ignite fusion in a fuel pellet.