Part of the issue is that this rocket doesn't just use hydrogen, it uses cryogenic liquid hydrogen, which apparently is even harder to manage. To quote from an

Part of the issue is that this rocket doesn't just use hydrogen, it uses cryogenic liquid hydrogen, which apparently is even harder to manage. To quote from an excellent writeup [0]: > Because it is so tiny, hydrogen can squeeze through the smallest of gaps. This is not so great a problem at ambient temperatures and pressures, but at super-chilled temperatures and high pressures, hydrogen easily oozes out of any available opening. Elon Musk responded to this article with the following tweet [1], which to my understanding is a pretty reasonable take: > 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. [0] https://arstechnica.com/science/2022/09/years-after-shuttle-nasa-rediscovers-the-perils-of-liquid-hydrogen/ https://arstechnica.com/science/2022/09/years-after-shuttle-... [1] https://twitter.com/elonmusk/status/1566233000458592256 https://twitter.com/elonmusk/status/1566233000458592256