Talk-Polywell.org

MSimon wrote: http://www.popularmechanics.com/science ... =pm_latest

Initially going to that link I got an ad for a propane grill...but then I continued on to the article. While the idea has been around for a long time and could work, I'm curious about the power source to do the pulsed fusion. We're still just an energy source away.

ScottL wrote:

MSimon wrote:http://www.popularmechanics.com/science ... =pm_latest

Initially going to that link I got an ad for a propane grill...but then I continued on to the article. While the idea has been around for a long time and could work, I'm curious about the power source to do the pulsed fusion. We're still just an energy source away.

Are we? Seems to me a good old-fashioned fission plant would work nicely.

JoeP wrote:

ScottL wrote:

MSimon wrote:http://www.popularmechanics.com/science ... =pm_latest

Initially going to that link I got an ad for a propane grill...but then I continued on to the article. While the idea has been around for a long time and could work, I'm curious about the power source to do the pulsed fusion. We're still just an energy source away.

Are we? Seems to me a good old-fashioned fission plant would work nicely.

Unless I'm mistaken, there are still regulations prohibiting fissionable materials powering spacecraft.

Unless I'm mistaken, there are still regulations prohibiting fissionable materials powering spacecraft.

No, there are not.
There are treaties prohibiting nuclear weapons in space. Nobody prevents you from using nuclear reactors (other some green nutbag protesters). Nuclear batteries are used quite often for deep space missions to jupiter and beyond as well as for spy satellites...
The article proposes the use of a SP 100 reactor.

Right. Almost all of our deep space probes use small thermoelectric generators powered by decaying fissionable products.

Even if there were or will be regulations making it legally impossible to put a big fission power plant on a spacecraft, that doesn't mean we do not have the requisite power source, it only means that we are unwilling to implement it as such.

Reminds me of this speculative plan: http://en.wikipedia.org/wiki/Project_Longshot

Skipjack wrote:

Unless I'm mistaken, there are still regulations prohibiting fissionable materials powering spacecraft.

No, there are not.
There are treaties prohibiting nuclear weapons in space. Nobody prevents you from using nuclear reactors (other some green nutbag protesters). Nuclear batteries are used quite often for deep space missions to jupiter and beyond as well as for spy satellites...
The article proposes the use of a SP 100 reactor.

Why haven't we started putting fission reactors on spacecraft? If there's no regulatory problems, then why not use larger reactors?

IIRC, we did put one or two fission reactors in space and the Soviets launched about thirty. In addition we've launched quite a few radioisotope thermoelectric generators which are very low power, something like 50 watts IIRC.

The problem with fission reactors in space has always been the fear they'll fall back to Earth with all the fission products. Whether that fear was understood or not, the way it has worked out has been with protests and anti-nuke propaganda basically reducing the space nuke program to nothing. This is why we have no nuclear rockets. The cause is primarily political, just as why we don't drill for oil on and around the continental US.

It's good to note though, that the greenies have so maligned the use of coal, gas and oil that nukes are getting more popular support, and if someone at NASA or the White House wanted to develop SP-100 or TRITON they could likely do it now. Note too that JIMO was cancelled not for political reasons but for budgetary ones. It included development of a space fission reactor and that work was moved to US Navy to continue. If anyone had a project where they needed something like SP-100, the US Navy would be able to jump to the rescue. We won't see that kind of expense for something like JIMO though.

I highly recommend the analysis of whether NASA's big budget flagship programs will endure through the current budget cuts found in this month's Space Quarterly. Basically, without a well defined mission, we can't expect to see space fission in the future. the only justification I can see for space fission in the near term would be something like if NASA decides to support the Mars One program:

http://www.youtube.com/watch?v=6QoEEGySGm4

This fusion thing at Marshall isn't a real development program. It's just another jobs program. The encouraging thing about it is Cassibry did his doctoral thesis on this work, so he's the instigator. It's not like the reactor was just given to Marshall because they had nothing better to do with it.

http://www.uah.edu/eng/departments/mae/ ... e-cassibry

The Idaho National Laboratory conducted three destructive tests of SNAP nuclear reactors at Test Area North prior to the launch of SNAP-10A.[11][12]The SNAPTRAN-3 destructive experiment, on April 1, 1964, simulated a rocket crash into the ocean, purposely creating a fireball and sending radioactive debris across the Idaho desert.

I really did love working out at INEL...I think the 16inch Battleship gun testing site was the coolest thing...


http://en.wikipedia.org/wiki/SNAP-10A

Why haven't we started putting fission reactors on spacecraft? If there's no regulatory problems, then why not use larger reactors?

Cassini... iirc...

Cassini used RTGs, which are not reactors.

Cassini used RTGs, which are not reactors.

No, but it contained "fissionable materials", which was the ScottL's original question.

the only justification I can see for space fission in the near term would be something like if NASA decides to support the Mars One program:

Very short sighted way of thinking as you inevitably get into a cat bites its tail situation: A mission is unfeasible without the technical capabilities in place, such as propulsion that enables short trip times. Yet you dont want to develop these without a mission in place. Putting the mission before the capabilities is the Apollo type of thinking. Apollo was great for a one shot stunt publicity stunt. It did not create a sustainable space infrastructure. The mission should be to provide the knowledge and technology needed. So that private companies like SpaceX can then use it to build a sustainable space infrastructure that will enable us to go anywhere we want and stay there. or at least return there as often as we want without having to wait years inbetween for the lack of money.

This fusion thing at Marshall isn't a real development program.

Why would you say that?

Related papers:

Conceptual Design of a Z-Pinch Fusion Propulsion System
Fusion Propulsion Z-Pinch Engine Concept