Liquid Oxygen/Liquid Hydrogen Auxiliary Propulsion System Thruster Investigation.
Abstract
This program encompassed the design, fabrication, and demonstration of a 111 newton (25 lb) thrust, integrated auxiliary propulsion system (iaps) thruster for use with LH2/LO2 propellants. Hydrogen was supplied at a temperature range of 22 to 33 K (40 to 60 R), and oxygen from 89 to 122 K (160 to 220 R). The thruster was designed to operate in both pulse mode and steady-state modes for vehicle attitude control, space maneuvering, and as abort backup in the event of failure of the main propulsion system. A dual-sleeve, tri-axial injection system was designed that utilizes a primary injector/combustor where 100% of the oxygen and 8% of the hydrogen is introduced; a secondary injector/combustor where 45% of the hydrogen is introduced to mix with the primary combustor gases; and a boundary layer injector that uses the remaining 45% of the hydrogen to cool the thrust throat/nozzles region. Hot-fire evaluation of this thruster with an BLC injection distance of 2.79 cm (1.10 in.) indicated that a specific impulse value of 390 sec can be attained using a coated molybdenum thrust chamber. Pulse mode tests indicated that a chamber pressure buildup to 90% thrust can be achieved in a time on the order of 48 msec. Some problems were encountered in achieving ignition of each pulse during pulse trains. This was interpreted to indicate that a higher delivered spark energy level (>100 mJ) would be required to maintain ignition reliability of the plasma torch ignition system under the extra 'cold' conditions resulting during pulsing. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1979
- Accession Number
- ADA079703
Entities
People
- E. E. Eberle
- L. Kusak