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UV-LED Completed Engineering Model Environmental and Performance Testing
UVLED feature image

HIGHLIGHT: The UV-LED team completed environmental testing of the engineering model (EM), on December 17, 2012. These tests included random vibration, shock, thermal vacuum and final performance testing. The EM met all requirements. The team is now building the flight unit.

BACKGROUND: Ultra Violet Light-Emitting Diodes (UV-LED) is a joint program between NASA/ARC, Stanford University and King Abdulaziz City for Science and Technology (KACST) in Saudi Arabia. Stanford University has developed some unique technology for the control of charge build-up on free-floating test masses critical to the operation of gravitational reference sensors (GRS) on drag-free spacecraft. Essentially, the GRS is an extremely accurate accelerometer that allows its host spacecraft to fly in an orbit defined solely by gravity, and not be affected by solar pressure and atmospheric drag. Its performance is limited in part by the charge build-up on its free-floating test mass.

The UV-LED system removes this charge by shining UV light on the test mass, creating a cloud of electrons through photoemission. The discharge rate is controlled with electrodes. Stanford University demonstrated this technology in the laboratory environment (TRL 4/5) and NASA/ARC is implementing the technology in a flight package that will be flown on a KACST spacecraft in the third quarter of 2013.

The program has two technical goals: flight qualification of new UV light emitting diodes, and the on-orbit demonstration of AC charge management. The success of UV-LED will increase the capability of gravitational reference sensors on future groundbreaking missions such as Laser Interferometer Space Antenna (LISA).

PROGRAM FUNDING: NASA/ARC, joint between Stanford University and KACST

ARC POC: Belgacem Jaroux, belgacem.a.jaroux@nasa.gov