The X-33 Program Takes Its Shape

by Andrzej Rucinski

The NASA X-33 Program, established in 1997, is designed to demonstrate the key design and operational aspects of a Single Stage to Orbit (SSTO) Reusable Launch Vehicle (RLV) rocket system. This approach is different from traditional launchers that by definition are disposable and thus expensive. It is also different from the space shuttle. The space shuttle is partially reusable, but the operation and maintenance costs are enormous. The RLV goal is to lower the cost from $10,000 per pound of payload to low earth orbit to $1,000 per pound. Another distinguishable characteristic of the RLV program is to operate using private venture capital and not federal funding. In order to encourage the private sector in developing such a commercially viable system, the program is conducted in two stages. The first one is the X-33 program that will lead to the development of an experimental, reduced scale vehicle used as a technology demonstrator. The second stage should result in a commercial space vehicle, called the Venture Star. More information pertinent to this project can be found at http://stp.msfc.nasa.gov/stpweb/x33/.

Currently, the X-33 is being assembled at Lockheed Martin Skunk Works in Palmdale, California. The space plane will be powered with a new type of aerospike engines that use liquid hydrogen and liquid oxygen. Two of the tanks should be available shortly at Edwards Air Force Base, California. The base has been designated as a testing center for X-33 with flights scheduled for early 2000. A total of 15 flights is planned. A major goal of these flights is the demonstration of the system’s capability to handle the heat during a full-scale RLV return from orbit.

UNH has been involved in the X-33 program for several years. The development effort was conducted by a multidisciplinary team of students, both undergraduate and graduates, through a grant sponsored by Sanders, a Lockheed Martin Company (see "ECE Department Goes Beyond High Tech," Signals & Noise, Summer 1997). The purpose of the project was to design an advanced concept Remote Health Node (RHN). Fifty RHNs are used on the X-33 to gather information about its parameters such as temperature, stress, etc. One of the challenges was to develop a reversible heat transfer mechanism to cool off the remote health node. This challenge has required very close cooperation among mechanical and electrical engineering students.