Probably they will switch as vehicles get into higher performance requirements. Alcohol&#x27;s a great fuel to work with: clean burning, room temp, good cooling properties, but it&#x27;ll be tempting to switch to something else when you need more performance--and have the money and experience to deal with the extra complexity. (And RP-1 isn&#x27;t that much worse, unless you have a particular problem with coking and a reusable engine, while it gives a noticeable increase in ISP. If you can handle the low density, methane&#x27;s nice and clean.)<p>But part of the new wave of space development is to optimize for cost and simplicity instead of performance, and you certainly can do real stuff with alcohol; many early rockets used it. It&#x27;s possible someone will keep using alcohol; Masten&#x27;s suborbital stuff might certainly stay that way. Doubt they&#x27;ll land on the Moon with alcohol, though.