Integrated solar upper stage alternate receiver
- General Atomics, San Diego, CA (United States)
The Integrated Solar Upper Stage (ISUS) receiver is a compact orbital transfer vehicle designed to generate thrust to boost transfer payloads from low earth orbit to Molniya or geosynchronous orbits. It can provide thrust by collecting and concentrating solar flux and heating hydrogen to {approximately} 2,500 K. Simultaneously, the ISUS receiver radiates heat into an array of thermionic converters to produce electrical power. The central component consists of a graphite body with rhenium lined internal passages. The alternate receiver relies on wrought rhenium that is rolled, machined and electron-beam welded to form a complex rhenium liner system within the graphite body. All machining operations were performed by molybdenum wire electron discharge machining. The tube forming procedure was performed to minimize the amount of cold work before annealing. Electron-beam welding was performed at a current density range of {approximately} 2 to 10 A/cm{sup 2} depending on material thickness, which melts the rhenium locally and results in a fine grained weld zone. A simplified Demonstration Test Assembly was fabricated and tested. The unit consisted of an inlet structure welded to a manifold with a simplified exhaust nozzle system and contained in a machined graphite body. The external graphite surfaces were coated with plasma sprayed rhenium for protection from graphite erosion. Testing included a hot hydrogen flow test to {approximately} 2,500 K. The main ISUS Alternate Receiver was designed and built according to the same procedures as the demonstration unit. However, the inlet and outlet plenums are more complex and are connected by 195 channels to efficiently transfer heat to the flowing hydrogen. An outlet tube containing a sonic orifice mates to the exhaust plenum.
- Sponsoring Organization:
- Department of the Air Force, Washington, DC (United States)
- OSTI ID:
- 347710
- Report Number(s):
- CONF-970701--
- Country of Publication:
- United States
- Language:
- English
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