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DownvoteEvangelist t1_j6ig1d2 wrote

Reply to comment by A_curious_fish in NASA tested new propulsion tech that could unlock new deep space travel possibilities by Creepy_Toe2680

They produce electricity and electricity powers electric motor... This wouldn't work in space...

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Shrike99 t1_j6jofu2 wrote

It would work if you added some propellant to the mix. For example, add a big water tank and use that electric motor to drive a pump that sprays the water out the back at very high pressure.

Realistically you're not going to get a very good exhaust velocity with that method, so you'd instead use a different kind of electric engine to accelerate the propellant; electrostatic, electrothermal, or electromagnetic.

Indeed, the only example to date of nuclear propulsion actually being used in space was on SNAP-10A, which featured a nuclear reactor powering an electrostatic engine with cesium as the propellant.

Granted, it only worked for about an hour before it broke down, but it did work. It's a shame there hasn't been any followup in the 58 years since then.

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DownvoteEvangelist t1_j6jv4q5 wrote

Probably because you don't get much thrust with that type of engine.

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Shrike99 t1_j6jxdxg wrote

We've had plenty of solar powered electric propulsion since. The Dawn mission was a great example of what electric propulsion can do. Solar power just doesn't scale up well to larger vehicles, or work very well as you get furthur from the sun.

A nuclear electric system has the potential to be much faster than a chemical rocket over long distances, i.e to Mars or especially beyond.

The real issue has been the reluctance to put nuclear reactors into space. SNAP-10A remains the only example the US has ever launched, even though much better designs like the SAFE-400 and KRUSTY have since been developed.

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