Christine Thropp
Sierra Nevada Corp. has wrapped up a critical design review of a 35,000 lbf thrust upper stage engine its Sierra Space subsidiary co-developed with the Air Force Research Laboratory.
The Vortex upper stage engine or VR35K-A demonstrated safe operation on the test stand, with Sierra Space also showcasing engine and equipment technical readiness, concept of operations as well as risk assessment and mitigation plans.
The upper stage liquid oxygen/liquid hydrogen engine is envisioned to produce more thrust power and higher specific impulse for increased capability. It features single-shaft turbo-pump assembly, stable combustion chamber and fuel-rich staged combustion cycle.
VR35K-A passed a preliminary design review in December 2020.
