James Webb Space Telescope microshutter arrays and beyond

UV capabilities of the CETUS multi-object spectrometer (MOS) and NUV/FUV camera

“…The Micro-shutter Array (MSA) planned for MOS is based on the prior work done by Goddard Space Flight Center for the JWST NIRSpec instrument. However, the implementation has evolved as the Goddard team of scientists and engineers have continued to develop the micro-shutter array technology 18 . The size of each individual shutter is 100 µm x 200 µm.…”

“…Figure18 -The FUV/NUV Camera has 2 separate channels: The FUV channel has a MCP which covers the 115-175 nm and the NUV channel has a CCD which covers the 180-400 nm range. In front of each channel is a filter wheel with filters to define sub-bands of interest.…”

Random Access Addressing of MEMS Electrostatic Shutter Array for Multi-Object Astronomical Spectroscopy

“…Microelectromechanical systems (MEMS) technology is therefore expected to be an enabling solution to construct an agile and compact reconfigurable multi slit array for a MOS in a remote unmanned observatory, and several possible configurations have been proposed by Riesenberg and Wuttig [ 12 ]. As a most advanced example, NASA Goddard Space Flight Center (GSFC) has developed a micro shutter array (MSA) for the James Web Space Telescope (JSWT), in which a matrix of micromechanical shutters coated with a thin-film magnetic material is used as reconfigurable apertures to select multiple objects at a time [ 13 ]. As an addressing mechanism, they used a combination of magnetic actuation and electrostatic latch; a permanent magnet is spatially scanned beneath the micro shutter array to choose a shutter column to open, and then individual shutter elements are latched by the electrostatic attractive force induced by the cross-bar like electrical addressing lines on the shutter substrate.…”

“…The research groups at the University of Tokyo, on the other hand, are constructing a new ground-based infrared telescope with a reflector of 6.5 m in diameter at the Tokyo Atacama Observatory (TAO) on a 5,640-m-high mountain in Chile [ 16 ], for which a MEMS type MOS shutter is development [ 17 , 18 ]. Owing to the transmissive optics design of the spectroscope, this work adopted a multi-slit device similar to the MSA for the JSWT [ 13 ] rather than a reflective optics using micro mirror array (MMA) [ 19 , 20 ]. Due to the collimator’s Rayleigh length, only a few millimeters in thickness is spared to accommodate the MOS shutter plate.…”

“…Setting aside the volume for the package, only 1 mm or less in thickness is used for the actuation mechanism. For this reason, the electrostatic actuation has been chosen for shutter addressing rather than a scanned magnet [ 13 , 21 ]. Another option for MEMS shutter was a roll-blind mechanism [ 22 , 23 ] that curls up as an initial state due to the difference of thermal expansion coefficients of the layered materials.…”