Volume 9, Number 5 • September/October 2001 • Aerospace Technology Development

Engine Technology Completes Aggressive Test Schedule

Stennis Space Center conducted the final test of a three-part test series of the Electro-Mechanical Actuator (EMA) technology used on the former X-33 program’s Linear Aerospike XR-2200 flight engine. Photo provided by Stennis Space Center.

The test team at NASA’s Stennis Space Center in south Mississippi successfully completed an accelerated test schedule with the third and final test of a three-part test series of the Electro-Mechanical Actuator (EMA) technology used on the former X-33 program’s XRS-2200 Linear Aerospike flight engine set. The test began at 7:58 p.m., Monday, August 6, and ran for a full 90 seconds, reaching the planned maximum power of 85 percent.

“This was a very aggressive test schedule,” said NASA’s Dr. Don Chenevert, EMA project manager at Stennis. “In less than three months, the test team brought the engine back on line and prepared it for the three hot-fire tests which began with a 5.32-second start-sequence test July 12. We couldn’t be more pleased with the program or the results.”

With the Linear Aerospike XRS-2200 flight engine set already mounted on the A-1 test stand when funding for the X-33 program was discontinued in March, testing of the EMA technology was a unique opportunity for NASA to effectively gain valuable experience and data from existing commercial technology.

The series was conducted as part of NASA’s Second-Generation Reusable Launch Vehicle Program—also known as the Space Launch Initiative. The program is led by NASA’s Marshall Space Flight Center in Huntsville, Alabama. The technology development program is designed to increase safety and reliability while reducing costs for space travel.

Electro-mechanical actuators electronically regulate the amount of fuel and oxidizer flowing to the engine. The new technology is a potential alternative and improvement to the older pneumatic and hydraulic-fluid systems currently used by the aerospace industry to drive and control critical rocket engine valves.

“Because every engine proposed by industry for a second-generation vehicle has EMAs, we took advantage of these aerospike engines already in position on the test stand at Stennis to explore this relatively new technology now—saving us valuable time later,” said Garry Lyles, Propulsion Projects Office manager of the Second-Generation Reusable Launch Vehicle Program at Marshall. “This data is critical toward developing the confidence required to support the use of these actuators on future launch vehicles.”

“This series of engine firings tested the actuator control system in what we call a ‘real condition of use’ environment,” said Dr. Chenevert. “Firing allows us to see how the integrated system handles the extreme cold of cryogenic propellants, the stress loads of the propellants pushing through the valves and the dynamic response to commanded flow rate changes. Additionally, we have many other unique conditions such as shock and vibration loads not found in a lab, so we capture more realistic data about the true performance of the actuators.”

The Rocketdyne Propulsion and Power Unit of The Boeing Company in Canoga Park, California developed the aerospike engine and supported the engine tests at Stennis. Q

For more information, contact Paul Foerman at 228/688-1880 or paul.foerman@ssc.nasa.gov Please mention you read about it in Innovation.

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