SpaceDev has completed a series of three hot-fire tests of its hybrid upper stage motor, the company announced Feb. 1.

The tests, conducted at the company’s test site in Orange County, Calif., demonstrated the ability to restart a partially spent motor grain and tested a new injector configuration.

The motor is being developed as part of the SpaceDev Streaker Small Launch Vehicle program. SpaceDev is developing its hybrid upper stage technology under contract with the U.S. Air Force Research Laboratory at Edwards Air Force Base.