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Fission seems like the better option for mars. The technology is ready now, and no one cares about a bit of nuclear waste on mars anyways.
by gpm 6y ago
Fission seems like the better option for mars. The technology is ready now, and no one cares about a bit of nuclear waste on mars anyways.
- Mediterraneo10 6y agoSpace probes require a minuscule amount of radioactive fuel, but launching that into space has still occasionally caused concern among environmentalists, as something might go wrong during launch. Can you imagine the resistance if someone wanted to launch enough processed uranium to support a Mars colony?
- nine_k 6y agoIf it's a pebble bed design, easily. Pebbles are uranium coated with multiple protective layers, extremely strong. They could be collected and reused if the launch vehicle plainly explodes on the launch pad.
- WJW 6y agoI think the problem is more when it explodes when the rocket is already going mach 10 and the resulting explosion scatters thousands of radioactive pebbles across several thousand square kilometres of Atlantic ocean, possibly hundreds of metres deep.
- Vecr 6y agoWhy's that a problem? The uranium won't leak out, the ocean will provide enough cooling, and even if it eventually does, it would be slowly and near the bottom, causing no problems at all.
- fpoling 6y agoThe problem with space probes is that the radioactive fuel is highly radioactive plutonium. If probe explodes and plutonium disperses in atmosphere, that causes thousands deaths via lung cancer. Uranium does not causes that.
- 08-15 6y agoEverything causes concern among environmentalists, even dihydrogen monoxide.
- pfdietz 6y ago235U is not very dangerous at all before it has undergone a chain reaction. The oceans contains tens of millions of tonnes of the isotope.
- trhway 6y agoyes, technically the next generation of Starships flying to Mars would be fission powered. Unfortunately the regulatory regime makes any fission related development close to impossible. Add to that practical unavailability of fission fuel - even NASA has issues getting those mere kilograms of plutonium, and even Musk wouldn't be able to get nor breeder reactor, nor enrichment plant (here on Earth i mean). As a result, the fusion "in 20 years" is much more plausible and feasible for the likes of SpaceX than fission.
- Hammershaft 6y agothe physics of Fission work better (or work at all, really) at scale. Fitting the weight and size of a fusion reactor on a rocket ship strikes me as impossible for the forseeable future.
- marcosdumay 6y agoFusion should lead to unbeatable specific impulses, so the huge size of a reactor may not be a problem at all. (Or maybe it is, I don't think anybody can be sure before there are actually working reactors out there.)
- tuatoru 6y agoSince we're talking about things that don't exist: - We should be able to beat fusion's Isp with direct matter to energy conversion. Certainly the mass of fuel needed will be 3 OM lower. Edit to add: Isp is a measure of velocity. The thing about velocity is, energy goes quadratically but momentum imparted to the vessel (the impulse) only goes linearly with velocity. Since no process can be 100% efficient, you're dealing with quadratically more and more waste heat from the engines. And space is an excellent insulator.
- marcosdumay 6y agoWell, if you create a nice way to make and store anti-matter, you would basically solve rocketry on any place that humans could ever care about going to. There are people researching that too, but not as many as fusion. And well, determining the capacity of things that don't exist is the first step on the work of making them exist.