Elon Musk: @SciGuySpace 准确评估。 Raptor 设计开始使用 H2，但改用 CH4。后者是高效率和易于操作的最佳组合。 对于大多数任务来说，H2 和 CH4 之间的 Delta-v 差异很小，因为 CH4 罐要小得多且不需要绝缘。

原推：@SciGuySpace Accurate assessment. Raptor design started out using H2, but switched to CH4. Latter is best combo of high efficiency & ease of operation imo.

Delta-v difference between H2 & CH4 is small for most missions, because CH4 tank is much smaller & no insulation is needed.
https://twitter.com/elonmusk/status/1566233000458592256