A quarterly research and development magazine.Two of the three ST5 satellites have on their top and bottom decks four-inchsquare arrays of micro-louvers. A single array includes some 2,600 individual electrostatically driven devices. Each device — grillwork and actuator together — is approximately the size of the cross on this letter “t.”
Sandia’s Microelectronics Development Laboratory fabricated and delivered 12 louver-laden wafers for the ST5 satellites to Johns Hopkins in October 2002. Johns Hopkins performed the packaging, integration, and space-qualification testing.
Each array weighs just grams and consumes nanowatts of power when changing states, from open to closed or vice versa, and no power (only voltage) to maintain a position.
In all, Sandia has 90 square centimeters of louvers flying aboard two of the three microsatellites, which have been in an elliptical polar orbit 200 to 3,000 miles above Earth since March 22. The threemonth experimental mission ended June 22, but as of late summer the satellites continued to operate.
“The MEMS variable-emittance louvers have performed successfully during their three-month mission,” says Ann Darrin, program manager at Johns Hopkins Applied Physics Lab. “This is the first time a fully space-qualified device of this type has ever been flown [in space], and the first to be flown on the outside of a satellite.”
“I'm kind of in awe that these MEMS devices are in space,” says Sandia’s Allen. “It’s a pretty cool milestone for MEMS devices. I think it’s great that Sandia could be a part of it.”
For information about the Space Technology 5
mission’s technology and detailed results, visit:
http://www.nasa.gov/st5
Johns Hopkins University Contact: Ann Darrin (240) 228-4952, Ann.Darrin@jhuapl.edu
Sandia Contact: John German (505) 844-5199, jdgerma@sandia.gov