Future Space Rocket Engines Tested
he first in a series of in-flight
qualification tests of a linear aerospike engine recently at NASA's Dryden Flight Research
Center, Edwards, California, may help lower costs in space access, achieve optimum performance
and efficiency, and create new space services and activities.
The NASA/Rocketdyne/Lockheed Martin Linear Aerospike SR-71 Experiment (LASRE), which includes a half-span, one-tenth-scale model of the RLV engine is being tested to power in 1998, and is designed to gather data on the aerospike's performance as it travels the transonic flight region.
Its plumbing and accessories are very similar to a normal rocket engine. The major difference is the absence of a bell-shaped nozzle. For optimum engine performance and efficiency, the atmosphere serves as part of the aerospike's nozzle with the rocket's exhaust plume contained in the surrounding airflowÑallowing it to compensate for atmospheric changes, unlike traditional rocket engines.
The linear aerospike's 75 percent shorter length design means less engine weight and less engine support structure required, allowing for a lighter vehicle and lower vehicle launch costs.
The model contains eight thrust cells of an aerospike engine mounted on a housing containing gaseous hydrogen, liquid oxygen and instrumentation and together are called the ''pod.'' The SR-71 takes off for aerial refueling with a tanker aircraft. With the piggy-backed LASRE pod, the SR-71 reaches an altitude between 20,000–80,000 feet.
Soon, the linear aerospike will be fired to collect accurate in-flight data on the interaction of the RLV's airflow and the linear aerospike engine and its exhaust plume. This data also will help determine the efficiency of the rocket engine.
Existing for more than 30 years, linear aerospike rocket engines have never flown until now. The technology at the time was considered too immature and was rejected by the Space Shuttle program. Now new material technology, modern performance sensors and monitoring controls enable split-second engine control with improved aerospike engine thrust cells modernized by additional laboratory tests and ground firings. More than a $500 million investment from Rocketdyne (a part of The Boeing Company) the Air Force and NASA has been made over the prior 30 years on aerospike technology.
NASA and industry are currently engaged in a cooperative agreement, the Reusable Launch Vehicle Program (RLV), to increase U.S. economic competitiveness and continued commercialization of the national space launch industry through the National Space Transportation Policy. The RLV program consists of both the X-33 and the X-34 technology demonstrators. The smaller X-34 will test the feasibility of launching small commercial and scientific payloads aboard a reusable rocket.
The X-33 is a technology demonstrator for a Single-Stage-To-Orbit (SSTO) RLV. The goal of the RLV technology program is to enable significant reductions in the cost of access to space, and to promote the creation and delivery of new space services and other activities that will improve U.S. economic competitiveness. The program implements the National Space Transportation Policy, which is designed to accelerate the development of new launch technologies and concepts to contribute to the continuing commercialization of the national space launch industry.
For more information, contact David Lux, at Dryden Research Center
Call (805)258-3695,
Fax: (805) 258-2793,
E-mail: Dave.Lux@dfrc.nasa.gov
or contact Carl Meade at the Lockheed Martin Skunk Works.
Call (805) 572-3908,
Fax: (805) 572-5798,
E-mail: Carl.Meade@Imco.com
Please mention you read about it in Innovation.
Arrows indicate the linear
aerospike engines on Lockheed
Martin's X-33 Advanced Technology Demonstrator.
X-33 linear aerospike engine diagram.
