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Science

OKIsItJustMe

(22,089 posts)

8. NERVA was not the same as Orion

Reply to eppur_se_muova (Reply #7)

Sat May 16, 2026, 02:06 PM

Yesterday

Orion was a proposal to use a series of nuclear explosions to power a spacecraft (a silly/insane idea IMHO, but one which keeps coming back!)

NERVA simply used a nuclear reactor as a heat source, instead of burning the fuel to provide the heat to expand the gases for propulsion. I don’t believe it would have been able to lift a spacecraft into orbit, however, it was considered for use on the upper stage(s) of the Saturn V.

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NASA Fires Up Powerful Lithium-Fed Thruster for Trips to Mars [View all] OKIsItJustMe Friday OP

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 Yesterday #2

The NERVA engine used hydrogen, so (you know) lithium is heavier than that, but certainly lighter than mercury OKIsItJustMe Yesterday #4

Hydrogen is being used there as ejectable mass, nothing more. It's handled by mechanical pumps and pressure. eppur_se_muova Yesterday #5

Check out the NASA paper I added to the bottom of the reply OKIsItJustMe Yesterday #6

Thanks for the paper. I knew about the older nuclear interest. eppur_se_muova Yesterday #7

NERVA was not the same as Orion OKIsItJustMe Yesterday #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 23 hrs ago #10

We both realize that (I was even repeating myself) OKIsItJustMe 23 hrs ago #12

Ah, OK ... writing for a larger audience ... eppur_se_muova 22 hrs ago #14

I've been watching "For All Mankind" on Apple TV OKIsItJustMe 21 hrs ago #15

Isn't lithium in somewhat short supply? erronis Yesterday #3

Meanwhile, at a grossly overspent under intellectual trump supported SpaceX 3825-87867 Yesterday #9

NASA is facing serious cuts OKIsItJustMe 23 hrs ago #11

More from the paper cited by OKIsItJustMe .... eppur_se_muova 22 hrs ago #13

"It must have been a real pleasure to work out the mathematics of MPD for the first time..." OKIsItJustMe 21 hrs ago #16