National Instruments
Austin, TX

NASA’s next-generation successor to the Hubble Space Telescope, the James Webb Space Telescope (JWST), features the Near Infrared Spectrograph (NIRSpec), which is equipped with more than 250,000 microshutters designed to observe thousands of distant galaxies to better understand the origins of the universe. The microshutters are microelectromechanical system (MEMS) devices that physically open and close for light exposure, similar to shutters on a camera. Engineers at NASA’s Goddard Space Flight Center in Maryland have tested the microshutters using National Instruments' LabVIEW FPGA to control the shutters in a test chamber.

NASA controlled the individual shutters withineach array using NI’s PXI-7813R data acquisition(DAQ) modules.

Said David Rapchun, lead testing engineer at Global Science and Technology/NASA Goddard, “The decision to go with commercial off-the-shelf hardware instead of a custom solution provided a more cost-effective method, and the control algorithm can be easily modified to improve testing, explore shutter issues, and otherwise further the development of the microshutters.”

Mink Hollow Systems, a National Instruments Alliance Partner, was selected by NASA to develop the FPGA software required for a test application that was capable of not only actuating each of the nearly 62,000 microshutters that are tested at one time, but also providing feedback on the design and estimating the life of each unit. The LabVIEW graphical development environment was selected to quickly develop the test software required to give engineers the ability to customize shutter actuation tests while monitoring and controlling the test environment. To control the opening and closing of the shutters, the LabVIEW FPGA was used to design a custom algorithm that could manage the synchronization required to open and close the shutters 240 times per minute.

The test system developed by Mink Hollow Systems is capable of testing the reliability of the microshutters for up to 100,000 cycles and on different shutter designs. This kind of testing would normally take years, but this system can cycle the shutters open and closed up to four times per second.

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NASA Tech Briefs Magazine

This article first appeared in the September, 2007 issue of NASA Tech Briefs Magazine.

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