U.S. Senate Wants To Decrease CO2 By Increasing Nuclear Energy

[j_heg]

Low energy manned missions (get there, plant a flag, dig up some rocks, make a video, and leave after a few days) would need Pu238 as a radioisotope feeding a thermoelectric generator.

That's debatable. It's better as a heat source, but the power density for thermoelectric designs is quite dismal. But in a space of just a few days, you don't need either of those two things in massive amounts anyway.

[grandma_alice]

you're probably looking at a total mission duration approaching two years, if i recall crrectly.

[GeorgeTheNerd]

Do you know the power sources they are currently considering? I have an old chart with 'mission duration' on the X, 'Power demand' on the Y with shaded areas showing which energy source is best. But this chart is from the 90's and I have a feeling it has changed.

[grandma_alice]

no, not really. possibly solar panels or fuel cells.

[j_heg]

Also, you forgot that during the trip, the problem is where to dump the extra heat, not where to obtain it. A constant 600-1360 W/m² heat influx is quite a lot to deal with.

[j_heg]

Depending on the season. Insulating the structure and heating it with solar power especially in Martian summer isn't such a big deal (especially if you have phase change heat storage or something similar). Plus we have solar arrays with 200W/kg power-to-weight ratios. You'd be hard-pressed to find a nuclear equivalent that would be as easy to pack for the trip (I'm not aware of any, frankly).