Stennis Space Center, Miss., has successfully completed a critical initial
test in a three-part series for a Space Launch Initiative (SLI) test program
of the Electro-Mechanical Actuator (EMA) technology used on the former X-33
program’s Linear Aerospike XRS-2200 flight engine set. The July 12 test was
a “start-sequence” test and went the full scheduled duration of 5.32

The test was a unique opportunity for NASA to effectively gain valuable
experience and data from existing commercial technology.

EMAs electronically regulate the amount of propellant (fuel and oxidizer)
flow in the engine. The technology is a potential alternative and
improvement to the older hydraulic-fluid systems currently used by the
aerospace industry to drive and control critical rocket engine valves.

According to NASA’s Garry Lyles, Space Launch Initiative Propulsion Program
Office manager at Marshall Space Flight Center, Huntsville, Ala., the EMA
technology is of interest to SLI because all engine concepts being
considered for the program 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,” Lyles said.
“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.”

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