NASA SBIR 2008 Solicitation

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
Tech-X Corporation
5621 Arapahoe Avenue, Suite A
Boulder, CO 80303 - 1379
(303) 448-0727

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Yongjun Choi
yjchoi@txcorp.com
5621 Arapahoe Ave Ste A
Boulder, CO 80303 - 1379
(303) 996-7522

Expected Technology Readiness Level (TRL) upon completion of contract: 3

TECHNICAL ABSTRACT (Limit 2000 characters, approximately 200 words)
Hall thrusters are being considered for many space missions because their high specific impulse delivers a larger payload mass fraction than chemical rockets. With a low thrust, however, Hall thrusters need to operate for a long period of time to achieve the necessary of the mission. For these missions, the lifetime requirements can reach into tens of thousands of hours. For Hall thrusters, the most important life-limiting process is the erosion of the channel walls. However, experimental verification of lifetime is time-consuming and expensive. Therefore, computational method is a useful tool to predict thruster lifetime. Many of the Hall thruster lifetime models were developed, and some of theses models gave quite promising results. However, while qualitatively interesting, the results did not match well with experiment. The reason of this discrepancy is that these numerical models assume electrons as a fluid. The proposed innovation will provide a better understanding of the erosion physics and will be useful for future thruster development with low cost and time. This tool also will allow to aid in the acceptance and implementation of Hall thrusters as a primary propulsion device through improving confidence of their long term reliability.

POTENTIAL NASA COMMERCIAL APPLICATIONS (Limit 1500 characters, approximately 150 words)
The erosion model proposed here would be of use to NASA personnel to predict the lifetime of Hall thrusters. The model also would allow for researchers to understand the effect of the operation conditions and the thruster geometry. It also would to aid in the acceptance and implementation of Hall thrusters as a primary propulsion device through improving confidence of their long term reliability.

POTENTIAL NON-NASA COMMERCIAL APPLICATIONS (Limit 1500 characters, approximately 150 words)
A kinetic molecular dynamic erosion model has numerous applications outside of the scope of NASA. There are a number of companies that develop electric propulsion system in US and other countries. All of these companies spent more than a thousand hours to test their thruster lifetime. They all need an accurate tool which can predict the lifetime for developing Hall thrusters. Recently, Space Systems/Loral has developed the BEPPA code for modeling plume interactions with spacecraft. They chose the detailed electron fluid model developed by Boyd at University of Michigan. It is known that the detailed model results are very sensitive to the channel exit conditions. The model proposed here can provide accurate initial conditions for plasma plume simulations for the hybrid model. Also, the MD method to model low energy xenon ion impact is of interest for fabrication of hard coatings such as cubic boron nitride or titanium nitride films. A kinetic molecular dynamic erosion model would offer a way to understand and help to optimize the deposition process with low cost.

NASA's technology taxonomy has been developed by the SBIR-STTR program to disseminate awareness of proposed and awarded R/R&D in the agency. It is a listing of over 100 technologies, sorted into broad categories, of interest to NASA.

TECHNOLOGY TAXONOMY MAPPING

Electromagnetic Thrusters