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Interpropellant Shaft Seal Solutions for Advanced Upper Stage Propulsion Systems


TECHNOLOGY AREA(S): Space Platforms 

OBJECTIVE: To develop innovative approaches for combine thrust management and interpropellant seal (IPS) systems for advanced upper stage and in-space propulsion systems engine turbopumps. 

DESCRIPTION: High pressures in an engine operating with independent turbopumps represent a significant leakage challenge to the IPS system for the liquid oxygen turbopump. The seal is required to separate the high pressure hydrogen used to drive the turbine from the high pressure liquid oxygen in the pump. Effective sealing systems must mitigate the loss of propellant vented through the IPS. 

PHASE I: Define requirements and a conceptual design for the LOX turbopump IPS which is traceable to an engine cycle for an advanced upper stage propulsion systems using hydrogen-oxygen. Conduct modeling, simulation, analysis, and/or laboratory experiments to evaluate the proposed concept IPS to enable an assessment of its impact on overall engine performance to include thrust management affects. 

PHASE II: Develop and demonstrate the IPS device at a scaled-up level, conduct additional modeling, simulation and experiments to characterize the operation. Testing should be performed at an appropriate facility to simulate the engine environment such that the propellant leakage and IPS performance can be investigated. Develop full-scale designs. 

PHASE III: This effort supports current and future DoD/NASA space launch applications. It will also support commercial space launch vehicle development. 


1: Sutton, G.P., "History of Liquid Rocket Engines," American Institute of Aeronautics and Astronautics, Reston, Virginia (2006).

2:  "Safe Use of Oxygen and Oxygen Systems: Guidelines for Oxygen System Design, Materials Selection, Operations, Storage, and Transportation," Beeson, H.D., Stewart, W.F., and Woods, S.S., American Society for Testing and Materials, Philadelphia, Pennsylvania (2000).

3:  Sutton, G. P., and Biblarz, O., "Rocket Propulsion Elements," 7th ed.

4:  Wiley-Interscience: New York (2000).

KEYWORDS: Interpropellant Seal (IPS), Turbopump, Oxygen, Hydrogen, Liquid Rocket Engine 


Joseph Mates (AFRL/RQRP) 

(661) 275-8089 

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