Why pure helium but not a mixture of helium-hydrogen? At some level [1] that mix is not flammable. That will add at least some additional payload. [1] https:/

Why pure helium but not a mixture of helium-hydrogen? At some level [1] that mix is not flammable. That will add at least some additional payload. [1] https://h2tools.org/bibliography/experimental-study-safety-helium-and-hydrogen-mixtures https://h2tools.org/bibliography/experimental-study-safety-h...