Northrop Grumman TR202 LOX/GH2 Deep Throttling Pintle Injector Fabrication and Demonstration Testing

NASA s Propulsion and Cryogenic Advanced Development (PCAD) project is developing enabling propulsion technologies in support of in support of the Exploration Initiative with a particular focus on the needs of the Altair Lunar Lander. To address Altair's need for deep-throttling cryogenic engines, PCAD has enlisted Northrop Grumman Aerospace Systems (NGAS) in a technology development effort associated with a LOX/LH2 expander cycle engine known as the TR202. This engine features independent turbopump assemblies and a variable area pintle injector similar to that used on the TR200 Apollo Lunar Module Descent Engine (LMDE). The TR202 program has completed a Conceptual Design (CoDR) of a possible throttling engine and has designed and built injector test hardware to demonstrate stable high performance over a 10:1 throttling range while providing the heat flux necessary to close the engine cycle. NGAS has partnered with NASA's Marshall Space Flight Center (MSFC), which supplied the ablative and calorimeter thrust chambers for the injector test program and provided the test facility as well as test and engineering support personnel. An extensive hot-fire test campaign comprising more than 50 tests was initiated and successfully completed during 2009 on MSFC's Test Stand 116 using pressure-fed liquid oxygen and gaseous hydrogen propellants. All planned test objectives were met. The test program was structured in two distinct phases: Phase 1 relied on ablative chambers to demonstrate injector hardware durability and to obtain early deep-throttling results, while Phase 2 used a water-cooled calorimeter chamber to obtain detailed performance and heat flux measurements at various power levels and mixture ratios. This paper focuses on the early part of the test program and describes final hardware build and test integration efforts, injector water flow testing, igniter and engine operational sequence development, and results from the ablative chamber tests. Challenges encountered during this phase of the program are outlined along with their eventual solutions. Details of the calorimeter chamber testing, injector performance results, and current program status are presented in companion papers (1,2).