Kerosene is a running fuel that is used as much as gasoline in the United States. Rockets use more efficient fuels like hydrogen. Now, however, NASA is designing the engine that will burn the kerosene. Although in 1969 the F-1 rockets that sent the Apollo spacecraft to the Moon used the kerosene, the current engine has a new design. The biggest difference is that it can be used several times: 50-100 times. That is a huge mission market.