Advanced Deuterium Fusion Rocket

[Diogenes]

For those of you who haven't seen it, this is pretty cool. It's video of the original tests of "Hotrod" the explosive powered prototype experiment for the Orion project.



http://www.youtube.com/watch?v=uQCrPNEsQaY

[MSimon]

You don't get criticality by adding neutrons.

[djolds1]

You don't get criticality by adding neutrons.

The point of Winterberg's concepts is to get rid of the primary; critical mass need not apply.

[parallel]

Here's another propulsion scheme. Next Big Future mentions the Polywell device being modified to produce thrust... http://nextbigfuture.com/2009/10/combin ... n-and.html
Wouldn't Bussard have been delighted if this came to pass?

[kurt9]

Brian Wang has pointed out two possibilities for space, depending on physics breakthroughs or not.

The first is the VASIMR plasma drive coupled with a solid-core fission reactor such as that being made by Hyperion. This is the option if we do not get any compact fusion power or anything like the Mach drive. This is the conservative option that does not require any new science. Only engineering work is necessary. This option still requires we come up with a separate Earth to LEO transportation method.

The second option is if we get both the polywell (or some other compact fusion source) and the Mach drive. If we get a Heim FTL, thats icing on the cake. This is the option we want. However, it is reassuring to know that we still have the solar system available to us (O'neill style) with the first option if all of this comes to naught.

[Diogenes]

Here's another propulsion scheme. Next Big Future mentions the Polywell device being modified to produce thrust... http://nextbigfuture.com/2009/10/combin ... n-and.html
Wouldn't Bussard have been delighted if this came to pass?

At one time I was constantly trying to start a discussion about using a polywell for propulsion. Specifically, I was speculating as to what a design would look like that could use the high speed alphas (from pb11 fusion) directly as reaction mass. For some reason, no one seemed to think the idea was worthy of discussion, though Tom Ligon did comment that Dr. Bussard had never envisioned using the alphas in this way.

Dr. Bussard had always planned to use the polywell to generate electricity to power some other propulsion engine, but it seemed to me that a lot of effort could be saved if the reactor itself could simply divert all the alphas into one direction.

Still think it is a worthy topic of discussion.

[djolds1]

At one time I was constantly trying to start a discussion about using a polywell for propulsion. Specifically, I was speculating as to what a design would look like that could use the high speed alphas (from pb11 fusion) directly as reaction mass. For some reason, no one seemed to think the idea was worthy of discussion, though Tom Ligon did comment that Dr. Bussard had never envisioned using the alphas in this way.

Dr. Bussard had always planned to use the polywell to generate electricity to power some other propulsion engine, but it seemed to me that a lot of effort could be saved if the reactor itself could simply divert all the alphas into one direction.

Still think it is a worthy topic of discussion.

Sounds a lot like Dr. Bussard's proposed "DFP" variant of Polywell-powered fusion rocket. Huge Isps, minuscule thrust, suitable for out-system exploration.

[D Tibbets]

Here's another propulsion scheme. Next Big Future mentions the Polywell device being modified to produce thrust... http://nextbigfuture.com/2009/10/combin ... n-and.html
Wouldn't Bussard have been delighted if this came to pass?

At one time I was constantly trying to start a discussion about using a polywell for propulsion. Specifically, I was speculating as to what a design would look like that could use the high speed alphas (from pb11 fusion) directly as reaction mass. For some reason, no one seemed to think the idea was worthy of discussion, though Tom Ligon did comment that Dr. Bussard had never envisioned using the alphas in this way.

Dr. Bussard had always planned to use the polywell to generate electricity to power some other propulsion engine, but it seemed to me that a lot of effort could be saved if the reactor itself could simply divert all the alphas into one direction.

Still think it is a worthy topic of discussion.

I believe Bussard's schemes included both a direct fusion product thrust and secondary accelerated fluid thrust depending on the ISP versus thrust power priorities.

http://www.ibiblio.org/lunar/school/Int ... stems.HTML

Dan Tibbets

[Mindblast]

At one time I was constantly trying to start a discussion about using a polywell for propulsion. Specifically, I was speculating as to what a design would look like that could use the high speed alphas (from pb11 fusion) directly as reaction mass. For some reason, no one seemed to think the idea was worthy of discussion, though Tom Ligon did comment that Dr. Bussard had never envisioned using the alphas in this way.

Dr. Bussard had always planned to use the polywell to generate electricity to power some other propulsion engine, but it seemed to me that a lot of effort could be saved if the reactor itself could simply divert all the alphas into one direction.

Still think it is a worthy topic of discussion.

Yes thats the DFP engine. See for instance here http://www.askmar.com/Fusion_files/QED% ... tation.pdf
On page 8 and 9 he describes the DFP engine.

Edit: This paper seems to have a more detailed description: http://www.askmar.com/Fusion_files/The% ... Engine.pdf
This is not quite what you proposed though, as it doesn't really direct the alphas into one direction but confines them to heat a propellant again. But the mixing ratios are really low here yielding extremely high ISPs.