Part 4/10:
One of the most significant advancements introduced with the Raptor engine is its use of methane as fuel, a departure from the kerosene used in Merlin. This decision stems from the challenges associated with reusability and in-situ resource utilization, particularly the need to produce fuel on Mars. Methane provides a balanced trade-off between efficiency and ease of handling, making it an ideal choice for the ambitious Starship program.