TEST ROCKET COULD POWER SPACECRAFT.

Byline: Jim Skeen Staff Writer

EDWARDS AIR FORCE BASE - NASA and the Air Force conducted the first-ever flights of an experimental rocket engine - called an aerospike - that could power future spacecraft.

The aerospike engine concept dates back to at least the 1960s, but while it has been the subject of analysis and ground tests there had never been an actual flight test - until the March 30 and 31 flights of two 10-foot-long solid-fueled rockets with aerospike nozzles.

``I thought, It's a rocket nozzle, why not put it on a rocket and shoot it up?'' said Trong Bui, a NASA Dryden Flight Research Center researcher and the project's principal engineer.

Essentially an inside-out rocket nozzle, an aerospike gets rid of the traditional bell-shaped nozzle, using atmospheric pressure instead to shape the exhaust plume.

The main advantage is that, as the rocket climbs, atmospheric and airstream pressure act on the exhaust plume to keep it at an optimum setting along the entire trajectory, officials of the National Aeronautics and Space Administration said.

The effort, called the Dryden Aerospike Rocket Test, has provided a wealth of information at relatively low cost. Dryden provided $75,000 in funding while the team's industry partners, Blacksky Corp. of Carlsbad, Calif., and Cesaroni Technology Inc. of Ontario, Canada, contributed about an equal amount.

``We're pleased with the data we got,'' said Bui. ``This database can be of help in the future to access-to-space vehicles.''

Dryden and the Air Force Flight Test Center developed the flight test concept, worked on the conceptual design of the aerospike engines, and are analyzing the data. Blacksky Corp. coordinated development of the experimental aerospike nozzles and solid propellant motors used in the tests with Cesaroni.

The tests were conducted at the King Ranch launch site at the Pecos County Aerospace Development Corporation Flight Test Range in Fort Stockton, Texas.

The rockets reached supersonic speeds in excess of Mach 1.5, roughly 1,000 mph, and peak altitudes of over 26,000 feet.

To keep costs down, off-the-shelf technology was used. The data from the flights was recorded on a 128-megabyte computer card, similar to those used in home personal computers.

``For many years, NASA Dryden has built small radio-controlled and remotely-piloted research models flown at subsonic speeds to explore new concepts such as lifting bodies, parafoil landing systems, and the testing of hypersonic shapes for landing feasibility,'' said Chuck Rogers, AFFTC project investigator. ``With the demonstration of this rocket flight test technique these models can now be tested at transonic and supersonic flight conditions at very low cost.''

Bui said he would like to see follow-on research. One project would be to see how the engine would perform if the spike at the end of the engine was cut off. If the performance is the same, weight could be saved by trimming the spike.

Researchers would also like to fly the aerospike engines at higher altitudes to measure performance.

Jim Skeen, [phone]

james.skeen(at)dailynews.com

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Photo:

Chuck Rogers of the U.S. Air Force Flight Test Center, from left, Trong Bui of Nasa Dryden Flight Research Center and Scott Bartel of Blacksky Corp. make preflight checks on a rocket.

NASA