GPIM AF-M315E Propulsion System
The NASA Space Technology mission Directorate's (STMD) Green Propellant Infusion Mission (GPIM) Technology Demonstration Mission (TDM) will demonstrate an operational AF-M315E green propellant propulsion system. Aerojet-Rocketdyne is responsible for the development of the propulsion system payload. This paper statuses the propulsion system module development, including thruster design and system design; Initial test results for the 1N engineering model thruster are presented. The culmination of this program will be high-performance, green AF-M315E propulsion system technology at TRL 7+, with components demonstrated to TRL 9, ready for direct infusion to a wide range of applications for the space user community.
Assessment of high performance HAN-monopropellants
There are several challenges presented with operating high performing monopropellants. Generally, along with high specific impulse, high performing monopropellants have high combustion temperatures. If a simple and reliable catalytic ignition approach is desired for high performing monopropellants, then new thruster designs are needed employing new catalyst and thermal materials. Before investing in the difficult task of materials and design development, we wanted to verify that high-performing monopropellant formulations could be safely handled, stored and ignited. This report discusses our efforts to formulate and test HAN-based monopropellants with very high specific impulse (270 seconds to over 280 seconds theoretical Isp). Seven formulations have been prepared, characterized and tested in a small cataTytically ignited rocket thruster. Six of the propellants showed good handling, storage, ignition, and combustion characteristics. Data from the short duration, laboratory-hardware tests is presented in this report. This report also begins to identify concepts and approaches to solving the catalyst/thermal bed material issue.*
Estimated Effects of Hydrazine Exposure on Cancer Incidence and Mortality in Aerospace Workers
Background: Animal studies suggest that hydrazine is a lung carcinogen, but human studies have been rare, rather small, and limited to cancer mortality. Methods: We examined cancer mortality and incidence in a cohort of aerospace workers with varying exposure to hydrazine contained in rocket fuels—extending previous mortality follow-up from 1994 to 2001 and investigating cancer incidence for the period 1988–2000 using population-registry data. We newly estimated hydrazine effects adjusting for occupational exposures to other carcinogens assessed through a job-exposure matrix. Rate-ratio estimates were derived from Cox proportional hazards and random-effects models using time-dependent exposure measures for hydrazine adjusting for trichloroethylene, polycyclic aromatic hydrocarbons, benzene, and mineral oil exposures. Results: Exposure to hydrazine was positively associated with lung cancer incidence (estimated rate ratio for high vs low exposure with 20-year lag = 2.5; 95% confidence interval = 1.3–4.9) and with colorectal cancer incidence (2.2; 1.0–4.6). Dose–response associations were observed for both outcomes; similar associations were found for lung cancer mortality but not for colorectal cancer mortality. Effect estimates for cancers of the pancreas, blood and lymph system, and kidneys were based on small numbers rendering our analyses uninformative, and patterns considering exposure levels and lags were inconsistent. Use of random-effect models did not change our results. Conclusions: The findings reported here are consistent with our previous results for lung cancer mortality; our new results suggest that exposure to hydrazine increases the risk of incident lung cancers. We also found, for the first time, an increased risk of colon cancers. Results for other cancer sites are inconclusive.