Revolutionary Microshutter Technology Hurdles Significant Challenges

This image shows a close-up view of the next-generation microshutter arrays during the fabrication process. The technology advances an already groundbreaking multi-object observing technique.
Image Credit: NASA/Bill Hrybyk

NASA technologists have hurdled a number of significant technological challenges in their quest to improve an already revolutionary observing technology originally created for the James Webb Space Telescope.

The team, led by Principal Investigator Harvey Moseley, a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, has demonstrated that electrostatically actuated microshutter arrays — that is, those activated by applying an specific voltage — are as functional as the current technology’s magnetically activated arrays. This advance makes them a highly attractive capability for potential Explorer-class missions designed to perform multi-object observations.

“We have identified real applications — three scientists want to use our microshutter arrays and the commercial sector has expressed interest,” said Mary Li, a Goddard engineer who is working with Moseley and other team members to fully develop this already groundbreaking observing technology. “The electrostatic concept has been fully demonstrated and our focus now is on making these devices highly reliable.”

Progress, she said, is in large part due to the fact that the team successfully eliminated all macro-moving parts — in particular, a large magnet — and dramatically lowered the voltage needed to actuate the microshutter array. In addition, the team applied advanced electronic circuitry and manufacturing techniques to assure the microshutter arrays’ dependable operation in orbit, Li added.

The Microshutter Breakthrough

Considered among the most innovative technologies to fly on the Webb telescope, the microshutter assembly is created from micro-electro-mechanical technologies and comprises thousands of tiny shutters, each about the width of a human hair.

Assembled on four postage-size grids or arrays, the 250,000 shutters open or close individually to allow only the light from targeted objects to enter Webb’s Near Infrared Spectrograph (NIRSpec), which will help identify types of stars and gases and measure their distances and motions. Because Webb will observe faint, far-away objects, it will take as long as a week for NIRSpec to gather enough light to obtain good spectra.

NIRSpec’s microshutter array, however, enhances the instrument’s observing efficiencies. It will allow scientists to gather spectral data on 100 objects at a time, vastly increasing the observatory’s productivity. When NASA launches the Webb telescope in 2018, it will represent a first for multi-object spectroscopy.

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