3 ms·
Wait but rockets don’t use fossil fuels, do they?
by whiddershins 5y ago
Wait but rockets don’t use fossil fuels, do they?
- Sharlin 5y agoOh, but they do. New Shepard uses liquid hydrogen, which is not a fossil fuel per se, but in practice hydrogen is currently made from fossil fuels. SpaceShipTwo uses HTPB which is a hydrocarbon oligomer, basically synthetic rubber, definitely a fossil fuel. Falcon 9 first stage engines use RP-1, a fancy type of jet fuel. The Starship first stage uses methane, a fossil fuel (although it could be made renewably as well). The Atlas V core stage uses RP-1 and the boosters HTPB. The Delta IV and Ariane 5 core stages use liquid hydrogen.
- nicoburns 5y agoA quick google says it took 2.90652E11 joules ~= 80MWh to get Saturn V to the moon. That seems like it'd actually be quite doable to do with renewables if you didn't need to fly too often.
- philipkglass 5y agoI think that must be something like imparted kinetic energy rather than chemical energy of the fuel it burned. This puts Apollo 16 fuel at 4.19E13 joules: https://space.stackexchange.com/questions/35155/what-rocket-system-launch-contained-the-highest-amount-of-propellent-potential-e https://space.stackexchange.com/questions/35155/what-rocket-... Still doable with renewables though. Assume 11639 MWh of fuel energy and 60% efficiency converting electricity to fuel. About 19,400 MWh total. That's 8 days of output from a 300 MW wind farm operating at 1/3 capacity factor.
- Qwertious 5y agoThe energy in rocket fuel has to come from somewhere. If it doesn't come from renewables, it's probably from fossil. For instance, most hydrogen production currently comes from heating up methane and steam for a CH4 + 2x H20 -> 4x H2 + CO2 reaction. So current hydrogen is just gas with extra steps.