Methane pressurization is easy, it's the same method used as with LOX. Getting rid of Helium simplifies the process enormously and is also the same route that S

Methane pressurization is easy, it's the same method used as with LOX. Getting rid of Helium simplifies the process enormously and is also the same route that SpaceX is going down, though at much larger scales. Also, a lot of people called out Scaled Composites on their choice of engine for Space Ship 1/2 as being a risk. Hybrids seem easy on paper and at small scale, but they have a lot of special difficulties once you scale up. The engines they're building out to be fairly simple, and lots of companies have built engines that size and actually with greater complexity without having prior experience.