ELI5. If the weight of rocket fuel is so important, why do SpaceX boosters waste a ton of fuel landing themselves?

Question

ELI5. If the weight of rocket fuel is so important, why do SpaceX boosters waste a ton of fuel landing themselves?

In: Engineering

Answer 1

1. They don’t use much fuel at all to land. The atmosphere does the majority of the deceleration. For example, the falcon 9 would have to time the final landing burn perfectly because the *minimum* thrust of one engine was enough to make the booster stage climb again. Minimum power of one engine was literally too much thrust to hover.

2. The amount of money they save by reusing their boosters is VASTLY more cost effective than having extra fuel and slightly more powerful engines to carry that fuel.