Electro-mechanical devices are core components in X-33 engine program

Spacecraft designers tested a critical start sequence of the Boeing Linear Aerospike XRS-2200 flight engine at the NASA Stennis Space Center, Miss., in July.

Sep 1st, 2001

By J.R. Wilson

STENNIS SPACE CENTER, Miss. — Spacecraft designers tested a critical start sequence of the Boeing Linear Aerospike XRS-2200 flight engine at the NASA Stennis Space Center, Miss., in July.

The 5.32-second test marked the start of a three-part Space Launch Initiative (SLI) test of the Electro-Mechanical Actuator (EMA) technology used on the X-33 single-stage to orbit program, which NASA cancelled earlier this year.

EMAs, which electronically regulate the level of propellant flow in the engine, are a potential alternative and improvement to the older hydraulic-fluid systems currently used to drive and control critical rocket engine valves. All of the engine concepts being considered for SLI use EMAs.

"SLI's primary focus is on technology development for concepts that would be able to dramatically reduce cost and improve safety and reliability of launching payloads for NASA, commercial and military missions," says Garry Lyles, SLI Propulsion Program Office manager at NASA's Marshall Space Flight Center in Huntsville, Ala..

"Since the engine was already in a test stand at Stennis, taking advantage of the dual aerospike flight engine set already in the A-1 test stand was too great of an opportunity to pass up," Lyles says.

Dr. Don Chenevert, EMA project manager at Stennis, says the second test will be a 25-second burn at 80 percent power-level. The third, scheduled for 100 seconds, will demonstrate relevant engine operations and show how the EMA control system works under actual thermal, hydraulic, and stress loads.

For more information contact the Boeing Space Systems division on the World Wide Web at http://www.boeing.com /defense-space /space/ propul/XRS2200.html.

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