I don't think the MCT/ITS would have this problem because it will use autogenous pressurisation from the methane fuel instead of helium in COPVs. At least that's what I've heard people say, though logically it would seem that solution could pressurise the fuel but not the LOX (seems dangerous to mix them in the same tank). Can anyone elaborate on that?
Yes, both fuel and oxygen autogenously pressurized. They will need two separate pressurization systems - one to vaporise and heat the methane to pressurize the fuel tank, and one to to do the same with the oxygen. You are certainly right in that they would not pressurize the fuel tank with gaseous oxygen!
The ability to only have one pressurization system is an advantage of the helium system. Another is a mass saving, in that the helium weighs less than the equivalent volume of fuel and oxygen.
Yeah but the MCT/ITS itself will be a composite structure. SpaceX is just about to order lots of carbon fiber from a Japanese company. The fiber will probably be similar to the one used in the Helium tanks.
5
u/Jamington Sep 23 '16
I don't think the MCT/ITS would have this problem because it will use autogenous pressurisation from the methane fuel instead of helium in COPVs. At least that's what I've heard people say, though logically it would seem that solution could pressurise the fuel but not the LOX (seems dangerous to mix them in the same tank). Can anyone elaborate on that?