NASA SBIR 2003 Solicitation


PROPOSAL NUMBER: 03- II A5.02-8171
SUBTOPIC TITLE: Nanotechnology
PROPOSAL TITLE: Carbon Nanotube Based Electric Propulsion Thruster with Low Power Consumption

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Changkun Dong
308 W. Rosemary Street
Chapel Hill, NC 27516-2548
U.S. Citizen or Legal Resident: Yes

Field emission electric propulsion (FEEP) thrusters have gained considerable attention for spacecrafts disturbance compensation because of excellent characteristics. The application of current FEEP has been slow in developing mainly caused by high specific power, which limit the milli-Newton thruster development due to insufficient onboard power. Dramatic field improvement from nanometer carbon nanotubes (CNTs) is a big advantage to increase the FEEP thrust more than 10 times under constant specific impulse (power). Phase I study showed a lower power consumption of 0.027 W/?YN from the CNT based ion source, comparing with the power consumption of 0.063 W/?YN from the traditional thruster. The CNT based FEEP ion source will be developed innovative in several aspects: integration of CNTs into the ion emission anode, buildup of the edge anode structure by the combination of the metal tip emitter and the slit emitter, and construction of a edge anode array capable of selective operation of different thrust unit. The power consumption of for ion thrust is expected to be reduced by a factor of 5 and more. The application of the room temperature carbon nanotube field emission electron neutralizer will further reduce the total power input to the ion engine.

Liquid metal ion source (LMIS) based focused ion beam (FIB) technique is used in different fields such as micro-fabrication and material analysis: secondary ion mass spectrometry (SIMS), accelerator mass spectrometry (AMS), high resolution self-assembled Monolayers (SAM) by the high energy FIB. As our knowledge, there is very limited companies are able to produce milliNewton thrusters. The success of this project will benefit not only the NASA space applications, also a large ion source markets.

Typical space missions of FEEP include: stationkeeping in geosynchronous Earth orbit (GEO), orbit repositioning, and orbital adjusting. For stationkeeping, FEEP can be used through the year with two firings per day. FEEP is presently baselined for several scientific missions, and has been proposed for attitude control and constellations. Applications of these thrusters as high-performance drag-free controllers for scientific spacecraft would result in considerable advantages from both weight and performance standpoints. Besides the space propulsion, elimination of electrostatic charge accumulation on spacecraft is another important task for electric ion source system.