A US Air Force Base located in California, recently played host to Sierra Space’s test campaign for the company’s new liquid oxygen and liquid hydrogen-fuelled upper stage engine. Sierra Space is a Colorado-based company and they have been able to succesfully complete their test campaigns for their new equipment.

Throughout this process, Research Laboratory (AFRL) worked with an aim of continuing to mature upper stage engines, with the intention of fulfilling future missions conducted by National Security Space Launch (NSSL). The purpose of NSSL missions is to assure that the US Department of Defence (DOD) is able to access space. It was back in 2018 when the US Air Force began the process of selecting their next generation NSSL vehicles, this proces is still ongoing.

Currently a VR35K-A makes use of a fuel-rich staged combustion cycle, turbopump architecture and combines this with Sierra Space’s patented VORTEX combustion chamber technology. The result of this, is the production of 35,000 lbf of thrust.

Records show that the use of hydrogen in space launches has been occurring since before the energy carrier’s current aim for climate-saving potential was established. It can be seen that NASA has been utilising liquid hydrogen since back in the early 1960s. Further to this, NASA launches have often used a combination of liquid oxygen and liquid hydrogen as a rocket propellant.

Vice-President of Engineering Solutions and Propulsion Systems at Sierra Space, Dan Polis, commented, “We are delivering high performance, reduced complexity and significant cost savings with this revolutionary new product, allowing our customers and partners to deliver up to 30% more payload mass to orbit.”

In 2021, Principal Investigator at the Cryogenics Test Laboratory, NASA’s Kennedy Space Center, Adam Swanger, stated, “Once you’re out of the atmosphere and you’re in space, that’s where liquid oxygen and liquid hydrogen really shine from a performance standpoint.”