The John C. Stennis Space Center completed the fourth in a series of large-scale hybrid motor tests Jan. 17 at 3:45 p.m. The 250,000-pound thrust hybrid rocket motor tested capitalizes on the safety and operational features of a liquid-propulsion system with the cost-savings potential of an inert solid propulsion system.

"The objective of this test was to address two key technical issues that hybrid rockets must overcome -- fuel retention at motor burnout and combustion stability," NASA's Gary Taylor, manager for the Hybrid Propulsion Demonstration Program at Stennis, said.

"The data generated by this test will move the large-scale hybrid rocket motor concept a giant step closer to operational use in future rocket propulsion applications."

The 250k-hybrid rocket motor was designed, fabricated and prepared for test by an industry consortium consisting of Lockheed Martin Astronautics, Boeing Rocketdyne, Lockheed Martin Michoud Space Systems, Thiokol Corporation and United Technologies Chemical Systems Division. The consortium will analyze the data from today's test and report to NASA on how stable the motor performed and how well the motor retained its fuel after this 27-second test firing.

"The hybrid system burns liquid oxygen with an inert solid fuel. The two propellants are separated in different tanks until motor ignition, making the system extremely safe," Taylor said. "The liquid oxygen is pumped into the fuel tank that also serves as the combustion chamber after ignition."

The hybrid rocket motor concept has been in existence for over 60 years, NASA's Boyce Mix, director of the Propulsion Test Directorate at Stennis, said. "The California Rocket Society was the first to test the hybrid rocket design in the United States. In April 1943, the group tested a system using oxygen and carbon. This rocket motor uses advanced propellants and is 70 inches in diameter, 45 feet long and weighs 125,000 pounds."

Taylor said the motor will now be disassembled, inspected and stored. The hardware will remain in NASA's possession and be available for future technology testing activities.