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OKIsItJustMe

(22,092 posts)
6. Check out the NASA paper I added to the bottom of the reply
Sat May 16, 2026, 12:30 PM
Saturday

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