Re: Why the Soyuzes can't stay more than 6 months
As far as I know, the Soyuz spacecraft uses the standard hypergolic storables N2O4/UDMH, not hydrogen peroxide. In any case, it is possible to add stabilizers to peroxide to make them storable over long periods of time. The main problem with peroxide is freezing, and the performance is poor compared to N2O4/UDMH.