Nuclear Thermal Propulsion

[DanS]

At a certain point, when education doesn't work, you have to just not let the eco-nuts bother you when they are in the distinct minority opinion. I think that some parts of our government are successful in doing so, including NASA, DoD, and the DoEnergy. NASA successfully launched Cassini, after all.

Please keep in mind that conventional nuclear reactors are only run at temperatures hot enough to create superheated steam (300F - 400F or so).

That hadn't occured to me. You're right in that this chamber temperature is at least an order of magnitude lower than most rocket engines.

The ion or magneto plasma dynamic engines (MPD) I described cannot operate in an atmosphere because the density of the gas will not allow the formation of a plasma.

I did not know that. That makes a lot of things clear to me. So we'll be using chemical engines at least as a first stage from Earth for a long, long time.

BTW - these things are generally classified as electric propulsion and MPDs are the state of the art (in my opinion).

I haven't really checked out MPDs, although I have checked out ion thrusters and Hall Effect thrusters because they are being used nowadays with fairly high frequency (especially the HETs since the late 90s). I assume by MPDs, you mean like that proposed in the VASIMR?

http://spaceflight.nasa.gov/shuttle/support/researching/aspl/vasimr.html

I think VASIMR has been canceled, or at least curtailed.

As an aside, NASA seems to be upping the power available from its proposed space nuclear reactor (Prometheus) being developed by the Department of Energy. It started at 50 KW. But now I'm starting to hear numbers like 100 KW or 200 KW. This might be useful in order to speed up propulsion, although I would prefer that they speed up development.

[pchang]

Yes. VASIMR is an example of an MPD (magneto plasma dynamic) engine.