NASA to test nuclear rocket engine that could take humans to Mars in 45 days

Jan 26, 2023
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Why does the article not mention speed and the physics of achieving it as well as the deceleration? Both transitions will greatly affect any passengers. I'm sure it's ability to accelerate will outstrip the astronaut's ability to withstand the G-force for the time required to attain maximum velocity, so the same will be true for slowing that thing down!
 
Dec 20, 2022
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Why does the article not mention speed and the physics of achieving it as well as the deceleration? Both transitions will greatly affect any passengers. I'm sure it's ability to accelerate will outstrip the astronaut's ability to withstand the G-force for the time required to attain maximum velocity, so the same will be true for slowing that thing down!
I imagine the advantage comes not from tremendous G-forces, but rather from the nuclear rocket's ability to propel the craft for a much longer time than a chemical rocket.

As I understand it, a chemical Mars rocket is essentially launched on a ballistic trajectory, depending on achieving the exact speed and direction at the moment the main engine shuts off, to carry the craft on the path to its rendezvous, at the point in Mars' orbit where Mars will be when the craft arrives. This is why it takes so long, because the vehicle is essentially coasting, for almost all of its journey. The reason the rocket doesn't continue to burn, to get there faster, is that that would require carrying so much fuel that the rocket couldn't even get off the ground.

The advantage of the nuclear rocket, as I understand it, would be that the nuclear rocket would be able to provide continuous, reasonable thrust, for a long period of time, with a much, much smaller weight of fuel. So it could continue to fire along the way, making for a greater top speed, while still allowing for turnaround and reverse thrust to slow down for landing.

I don't know what sort of max thrust the nuclear rocket could produce; they might use a chemical rocket booster to get it into space, before turning on the nuke.
 

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