Sierra Nevada Corp (SNC) had decided to shut down its propellant office building hybrid rocket engines in California after Virgin Galactic decided to change its rocket engine from a plastic based propellant burning hybrid built by SNC to one burning a rubber compound of its own design.  No job losses are expected, though SNC did lay off 100 workers earlier this year after it lost out to Boeing and SpaceX for funding in the next stage of the NASA Commercial Crew Programme.