Search Results

A three-year program to develop a Direct Drive Hall Effect Thruster (D2HET) system began 15 months ago as part of the NASA Advanced Cross-Enterprise Technology Development initiative. The system is expected to reduce significantly the power processing, complexity, weight, and cost over conventional low-voltage systems. The D2HET will employ solar arrays that operate at voltages greater than 300V, and will be an enabling technology for affordable planetary exploration. It will also be a stepping-stone in the production of the next generation of power systems for Earth orbiting satellites. This paper provides a general overview of the program and reports the first year's findings from both theoretical and experimental components of the program.

Five type 4 all-composite compressed natural gas (CNG) fuel tanks produced in 1994 were acquired to study the effects of time and environmental exposure. Tank durability was demonstrated by the ability of the tanks to meet or exceed the ANSI/CSA NGV2-20001 standards after 9 years of field service. All tanks passed the NGV2-2000 standard production test requirements, including hydrostatic pressurization testing and standard leak testing. NGV2-2000 design qualification tests were performed on three of the tanks. Design qualification testing included liner and composite mechanical properties, cyclic pressurization, burst testing, and permeation testing as defined by NGV2-2000. All tanks exceeded the NGV2-2000 test requirements and exhibited no adverse effects from time, environment, and cyclic pressurization.