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OKIsItJustMe

(22,089 posts)
6. Check out the NASA paper I added to the bottom of the reply
Sat May 16, 2026, 12:30 PM
12 hrs ago

Last edited Sat May 16, 2026, 02:23 PM - Edit history (2)

As well as this one linked to in the OP. https://alfven.princeton.edu/publications/pdf/polk-iepc-2024.pdf

I gave you the wrong impression by citing the NERVA engine, which, as you say, used a nuclear reactor to heat hydrogen which was then used as a propellant. My (unclear) point was that nuclear-powered engines have been being researched by NASA (and its predecessors) since the mid-50’s.

In the case of the “MPD thruster,” the hydrogen is being used as a plasma.
https://en.wikipedia.org/wiki/Magnetoplasmadynamic_thruster

Psyche uses xenon gas in its ion thrusters.


I read once that Gene Roddenberry rejected the use of ion thrusters for the Enterprise because they were too slow. (In the original series, they occasionally encountered more primitive spaceships which used them — as I recall Khan’s Botany Bay used ion thrusters.)

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Another fucking waste of money. 3Hotdogs Yesterday #1
Previous ion engines have favored very heavy atoms as propellant -- mercury or xenon. More atomic mass -- eppur_se_muova 22 hrs ago #2
The NERVA engine used hydrogen, so (you know) lithium is heavier than that, but certainly lighter than mercury OKIsItJustMe 13 hrs ago #4
Hydrogen is being used there as ejectable mass, nothing more. It's handled by mechanical pumps and pressure. eppur_se_muova 12 hrs ago #5
Check out the NASA paper I added to the bottom of the reply OKIsItJustMe 12 hrs ago #6
Thanks for the paper. I knew about the older nuclear interest. eppur_se_muova 11 hrs ago #7
NERVA was not the same as Orion OKIsItJustMe 10 hrs ago #8
Yes, I know that, thank you. In fact you're just repeating things I've already said in my replies. nt eppur_se_muova 8 hrs ago #10
We both realize that (I was even repeating myself) OKIsItJustMe 8 hrs ago #12
Ah, OK ... writing for a larger audience ... eppur_se_muova 6 hrs ago #14
I've been watching "For All Mankind" on Apple TV OKIsItJustMe 6 hrs ago #15
Isn't lithium in somewhat short supply? erronis 14 hrs ago #3
Meanwhile, at a grossly overspent under intellectual trump supported SpaceX 3825-87867 8 hrs ago #9
NASA is facing serious cuts OKIsItJustMe 8 hrs ago #11
More from the paper cited by OKIsItJustMe .... eppur_se_muova 6 hrs ago #13
"It must have been a real pleasure to work out the mathematics of MPD for the first time..." OKIsItJustMe 6 hrs ago #16
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