RocketMotorTwo
RocketMotorTwo (RM2) is a family of hybrid rocket engines that are being developed for the Scaled Composites SpaceShipTwo suborbital spaceplane.
The first-generation engine was developed by Sierra Nevada Corporation (SNC), from the late 2000s to May 2014. It was first ignited in flight during a SpaceShipTwo test launch in April 2013. This engine design was subsequently flown in only two additional flight tests during 2013 and January 2014. SNC was a subcontractor to Scaled Composites through May 2014 when their involvement in the program ended after Virgin Galactic elected to replace SNC's version of RocketMotorTwo powered by HTPB rubber fuel, with its own internally developed hybrid motor for SpaceShipTwo.
The second-generation RocketMotorTwo engine is a variant of the earlier SNC basic design, but is fueled by polyamide plastic fuel, while continuing to use the same nitrous oxide oxidizer. The second-generation engine is now made in-house by Virgin Galactic rather than by SNC.
RocketMotorTwo is a hybrid rocket engine utilizing solid hydroxyl-terminated polybutadiene (HTPB) fuel and liquid nitrous oxide oxidizer – sometimes referred to as an N2O/HTPB motor – providing 60,000 pounds-force (270 kN) of thrust. The design makes use of lessons learned during the development of the SpaceShipOne hybrid rocket motor.
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