A hybrid rocket motor underwent a successful test firing at NASA Stennis Space Center (SSC) recently, using a motor similar to one used in a sounding rocket.
Sounding rockets take their name from the nautical term “to sound,” which means to take measurements. The rockets carry payloads of various weights to altitudes of more than 800 miles.
Hybrid motors are comparable to the Solid Rocket Motors (SRMs) used as sounding rockets or rocket boosters because they both use solid fuel – unlike Liquid Rocket Engines, which are fueled by liquid hydrogen or kerosene. But unlike SRMs, the combustion rate of hybrid motors can be controlled.
Once SRMs fire, they continue to burn until the fuel expires. Hybrid motors use liquid oxygen to burn the solid fuel, which provides thrust. The amount of oxygen used can be controlled, which means the rate of combustion (or thrust) can be controlled – even turned off.
Lockheed Martin Space Systems Co. – Michoud Operations designed and fabricated the motor tested at SSC. The motor demonstrated critical hybrid rocket motor fuel technologies.
“The testing at Stennis demonstrated the structural integrity of our fuel-grain design as we continue to advance the state of the art for hybrid rocket motors,” said Tim Knowles, Lockheed Martin’s principal investigator for hybrid rocket motors.
The fuel of the motor tested at SSC is a rubberized compound, HTPB (hydroxyl terminated polybutadiene). The motor was fired for the full planned duration and met all test objectives.
“We made a lot of progress to get to this point,” said Robert Ross, project manager of SSC’s Hybrid Technology Test Project. “The Stennis team did an outstanding job. We had a critical deadline to get the test done, and our team finished the job two days early.”
