Accession Number:

ADA463085

Title:

Analysis of the Electrospray Plume from the EMI-Im Propellant Externally Wetted on a Tungsten Needle

Descriptive Note:

Conference paper

Corporate Author:

AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE

Personal Author(s):

• Chiu, Yu-Hui
• Gaeta, Geraldine
• Heine, Thomas R.
• Dressler, Rainer A.
• Levandier, Dale J.

Report Date:

2006-07-01

Pagination or Media Count:

9.0

Abstract:

The room temperature ionic liquid propellant, 1-ethyl-3-methylimidazolium bistrifluoromethylsulfonylimide EMI-Im is being tested for the NASA DRS-ST7 mission. A capillary thruster configuration is planned for ST7, and time-of-flight experiments have shown that the spray of EMI-Im produces a mixture of primarily droplets and low levels of ions, resulting in a low specific impulse. Recently, pure ion emission was achieved for EMI-Im in a wetted needle thruster, suggesting that this propellant, which has passed all space environmental exposure tests, may also be a candidate for high specific impulse missions. The use of wetted tips raises the question whether electrochemistry at the liquid-metal interface causes significant propellant fouling that -will ultimately result in performance degradation due to the significantly longer propellant metal interaction times in comparison with the capillary design and-the higher flow rates. Electrochemical fouling can be mitigated through a polarity alternation approach, which adds complexity to the power processing unit.

Descriptors:

• *EMISSION
• *IONS
• *LIQUID ROCKET PROPELLANTS
• *MASS SPECTROMETRY
• *THRUSTERS
• SYMPOSIA
• ELECTROCHEMISTRY
• TUNGSTEN
• NEEDLES
• PLUMES

Subject Categories:

• Combustion and Ignition
• Liquid Propellant Rocket Engines
• Liquid Rocket Propellants

Distribution Statement:

APPROVED FOR PUBLIC RELEASE