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It won’t use the raptors to land on the moon.
by tigershark 5y ago
It won’t use the raptors to land on the moon.
- ChuckMcM 5y agoThe question isn't raptors or something else, the question is mass. In order to decelerate, you throw mass at high speed out the other send. That is typically a small mass (the exhaust gases) hitting the moon at a high velocity. The larger the mass you are trying to land, the more momentum you are going to transfer to the regolith and dust under the lander. As the referenced paper points out, it is pretty easy to get that stuff up to escape velocity which has it leaving the moon on its own journey into space.
- tigershark 5y agoIt will use the raptors to decelerate and hot gas trusters to land in the last 10s of metres to avoid this problem. From wiki: “ The variant will use high‑thrust oxygen- and methane-fueled thrusters located mid‑body on Starship HLS during the final "tens of meters" of the terminal lunar descent and landing to avoid plume impingement problems with the lunar regolith.” Potentially they could also brake down to 0 velocity when they switch to the thrusters and land at 0.1M/s, but they obviously won’t do that because it’s just a waste of fuel.