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NexGen Micro-Shutter Array

Multi-object spectroscopy (MOS) is a technology development priority of the Cosmic Origins Program. Aperture control methods that are popular in ground-based MOS applications (e.g., robotically configured fibers and punch plates) are not practical options for spaceflight. Microshutter array technology solves this problem. A microshutter array functions as a programmable slit mask. The array can be programed to provide any pattern of slits corresponding to sparsely distributed sources on the sky (similar to a punch plate). It can also be programmed to provide shaped slits on extended sources. Our first generation micro-shutter technology enabled realization of the James Webb Space Telescope (JWST) Near Infrared Spectrometer (NIRSpec). This prior generation technology involved a combination of electrostatic and magnetic actuation that results in a heavy complex mechanical assembly that does not scale to larger formats required by strategic mission concepts that are under study for the 2020 Decadal Survey.

Our NexGen Micro-Shutter Array (NGMSA) technology eliminates the magnetic actuation aspect, resulting in a shutter array that is scalable to very large formats with very low mass, no external mechanical complexity, and no life-limited mechanical components. This major breakthrough has been demonstrated to TRL-9 in small 128 x 64 arrays of 200 x 100 micron shutter pixels.

Micro-shutter arrays (top) are used to select multiple astronomical targets to enable their spectra to be simultaneously measured (bottom); Each micro-shutter is similar in size to a human hair and can be commanded opened or closed to match the position of targets in any astronomical field.
Micro-shutter arrays (top) are used to select multiple astronomical targets to enable their spectra to be simultaneously measured (bottom); Each micro-shutter is similar in size to a human hair and can be commanded opened or closed to match the position of targets in any astronomical field.

Recognizing the fundamental advantage of microshutters, and the need for a technology that can be scaled to large format arrays to meet the MOS requirements of the Astrophysics Division Strategic Plan, we have anchored development of the NGMSA to the following mission applications: the Large UltraViolet Optical InfraRed surveyor (LUVOIR), the Habitable Exoplanet surveyor (HabEx) strategic-class missions, the Cosmic Evolution Through UV Spectroscopy (CETUS) probe-class mission, as well as the ongoing Far-ultraviolet Off Rowland-Circle for Imaging and Spectroscopy (FORTIS) sounding rocket program as a flight test platform. This team includes collaborators from these mission studies to insure that the technology developed under this SAT project aligns with their respective "pull technology" requirements. The current TRL status to the above mission applications is shown in the table below. This proposal is responsive to the TCOR priority technology gap entitled "High- efficiency UV multi-object spectrometers."

Actuation of a 64X128 microshutter array on our newly developed automated testing station. This test station enables us to functionally evaluate shutter arrays prior to packaging and assembly processes.
NGMSA TRL Status: as of December 2019
  FORTIS CETUS HabEx LUVOIR
Array Format (pixels) 128 x 64 365 x 171† Mosaic: n x m
840 x 420		 Mosaic: n x m
840 x 420
Pixel Pitch (microns) 200 x 100 200 x 100 200 x 100 200 x 100
Mosaic Format NA NA 1 ≤ n, m ≤ 2
Depending on telescope aperture		 1 ≤ n, m ≤ 2
Depending on telescope aperture
Current TRL 9 4 4 4

† CETUS current format assumption shown for reference. Development of the 840x420 three side buttable format is the current focus of this SAT project.