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stewartm0205 t1_j2bs81v wrote

Reply to comment by Reddit-runner in What if we kept pursuing nuclear spacecraft propulsion? by rosTopicEchoChamber

In space, a NTR wouldn’t need much shielding. In space, a tank wouldn’t need much insulation.

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Reddit-runner t1_j2ctl6v wrote

Wrong.

You need heavy shielding to not irradiate the payload

And the insulation is necessary because the tanks are in constant exposure to the sun.

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stewartm0205 t1_j2fin05 wrote

The reactor is at the other end of the rocket far away from the payload in the high radiation environment of space. At worse, a small block of material should be enough of a shield. The radiation will dissipate at square the distance from the reactor. Then it had to penetrate the liquid hydrogen in the tank. As for the tank, a shiny thin Mylar sheet would be enough to reflect the rays of the sun. The Vacuum of space makes for a perfect insulator.

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Reddit-runner t1_j2fxmzm wrote

> The Vacuum of space makes for a perfect insulator.

Yeah, that's the problem. Do the math

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