Recent comments in /f/space

axialintellectual t1_j7mjsi4 wrote

Reply to comment by MrMunchkin in The James Webb Space Telescope just found an asteroid by total accident, its smallest object yet by pecika

JWST doesn't. In this case, it's arguable (they picked it up on calibration data, which are taken regularly) that it sort of did, but given Webb's limited lifetime and extreme pressure on observing time, it's essentially always being directed to look at something, calibrating, or changing its orientation. It's not an automated survey telescope!

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Shrike99 t1_j7mj99t wrote

Reply to comment by thuanjinkee in Rolls-Royce Nuclear Engine Could Power Quick Trips to the Moon and Mars by darthatheos

It's still extremely inefficient. 100kg worth of plutonium pellets in some RTGs will produce about 50 kilowatts of thermal power. 100kg of plutonium in an SMR on the other hand could easily provide 500 megawatts of thermal power.

The average US household has an average power draw of about 1.3 kilowatts, so assuming 100% conversion efficiency in the above cases, the RTGs could power about 38 houses while the SMR could power about 38,500 houses.

Given how expensive plutonium is, that thousand-fold difference makes RTGs a complete non-starter. And in practice an SMR would actually use uranium which is much cheaper, making things even worse.

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