&lt;title&gt;Magnetically actuated microshutter arrays&lt;/title&gt;

Mott, D. B.; Aslam, Shahid; Blumenstock, Kenneth A.; Fettig, Rainer K.; Franz, David E.; Kutyrev, A.; Li, Mary J.; Monroy, C.; Moseley, S. H.; Schwinger, D. S.

doi:10.1117/12.443109

Cited by 10 publications

(6 citation statements)

References 6 publications

(6 reference statements)

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“…It involves magnetic actuation and electrostatic latching and addressing. 13,14 The shutters are coated with a high permeability soft magnetic material CoFe (∼ 90%Fe and 10% Co). CoFe is a soft magnetic material with low residual magnetization.…”

Section: Microshutter Array Design and Principles Of Operationmentioning

confidence: 99%

Microshutter arrays: high contrast programmable field masks for JWST NIRSpec

Kutyrev

Collins

Chambers

et al. 2008

Space Telescopes and Instrumentation 2008: Optical, Infrared, and Millimeter

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Microshutter arrays are one of the novel technologies developed for the James Webb Space Telescope (JWST). It will allow Near Infrared Spectrometer (NIRSpec) to acquire spectra of hundreds of objects simultaneously therefore increasing its efficiency tremendously. We have developed these programmable arrays that are based on Micro-Electro Mechanical Structures (MEMS) technology. The arrays are 2D addressable masks that can operate in cryogenic environment of JWST. Since the primary JWST science requires acquisition of spectra of extremely faint objects, it is important to provide very high contrast of the open to closed shutters. This high contrast is necessary to eliminate any possible contamination and confusion in the acquired spectra by unwanted objects. We have developed and built a test system for the microshutter array functional and optical characterization. This system is capable of measuring the contrast of the mciroshutter array both in visible and infrared light of the NIRSpec wavelength range while the arrays are in their working cryogenic environment. We have measured contrast ratio of several microshutter arrays and demonstrated that they satisfy and in many cases far exceed the NIRSpec contrast requirement value of 2000.

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Section: Microshutter Array Design and Principles Of Operationmentioning

confidence: 99%

Microshutter arrays: high contrast programmable field masks for JWST NIRSpec

Kutyrev

Collins

Chambers

et al. 2008

Space Telescopes and Instrumentation 2008: Optical, Infrared, and Millimeter

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“…Individual shutters are designed with a torsion flexure hinge and are magnetically actuated by scanning a permanent tripole magnet across the MSA and electrostatically held open to allow the high-contrast transmission of light from specific celestial objects into NIRSpec. The selective nature of the MSA is achieved electrostatically via a threevoltage level, cross-point addressing scheme operating on orthogonally oriented column and row electrodes driven by external electronics [4,5].…”

Section: Microshutter Array Designmentioning

confidence: 99%

Cryogenic characterization and testing of magnetically-actuated microshutter arrays for the James Webb Space Telescope

King

Kletetschka

Jah

et al. 2005

J. Micromech. Microeng.

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Two-dimensional MEMS microshutter arrays (MSA) have been fabricated at the NASA Goddard Space Flight Center (GSFC) for the James Webb Space Telescope (JWST) to enable cryogenic (-35 K) spectrographic astronomy measurements in the nearinfrared region. Functioning as a focal plane object selection device, the MSA is a 2-D programmable aperture mask with fine resolution, high efficiency and high contrast. The MSA are closepacked silicon nitride shutters (cell size of 100 x 200 pm) patterned with a torsion flexure to allow opening to 90 degrees. A layer of magnetic material is deposited onto each shutter to permit magnetic actuation. Two electrodes are deposited, one onto each siiuiier and another onio the support snucmre side-waii, permitting electrostatic latching and 2-D addressing. New techniques were developed to test MSA under mission-similar conditions (8 K 5 T < 300K). The "magnetic rotisserie" has proven to be an excellent tool for rapid characterization of MSA. Tests conducted with the magnetic rotisserie method include accelerated cryogenic lifetesting of unpackaged 128 x 64 MSA and parallel measurement of the magneto-mechanical stiffness of shutters in "pathfinder" test samples containing multiple MSA designs. Lifetest results indicate a logarithmic failure rate out to -10' shutter actuations. These results have increased our understanding of failure mechanisms and provide a means to predict the overall reliability of MSA devices.

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“…By changing the satellite's emissivity, the heat radiated into space can be controlled. , and a magnetically actuated shutter 15 .…”

Section: Mems In Satellite Thermal Controlmentioning

confidence: 99%

Development of a Microelectromechanical System for Small Satellite Thermal Control

Beasley¹

2004

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Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. AbstractTrends in space technology require future satellites to be smaller and cheaper than their contemporary counterparts. This new direction requires a similar evolution in thermal control. Previous techniques such as heat pipes and conventional radiators have large masses themselves and are not scaleable to fit these smaller designs. Microelectromechanical Systems (MEMS) offer unique advantages in mass and scalability. By coating a satellite with thousands of MEMS devices, thermal control can respond to variations in thermal capacity.This project involved the development of a variable radiator that would control a satellite's temperature by changing the heat conduction between the satellite and a MEMS surface coating. These MEMS devices operate by using a voltage to deflect an emissive surface layer into thermal contact with the structure below. By designing for a voltage of 20 to 24V, these devices can operate on the bus voltage supplied by many satellites produced today. Testing has shown that these devices operated at this desired voltage level.The electromechanical and thermal properties of the device were modeled. These models provided insight into the design dimensions that dominated the voltage and power characteristics as well as the heat flow. The devices were tested for both their thermal and electrostatic properties. The modeling predictions were found to be accurate for the required device voltages. With the insight gained from modeling and testing, a new design was made offering greater thermal performance while maintaining low operating voltages. This design incorporated different materials allowing easier device fabrication and higher wafer yields. It also used different physical dimensions to improve thermal performance.Finally, this project developed the packaging requirements of this device for flight on the MIDSTAR I satellite. The groundwork has been laid for its flight into space in 2006 through a package design specific to this device. The Interface Control Document outlining hardware interfaces, power specifications, and satellite orientation has been completed.

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<title>Magnetically actuated microshutter arrays</title>

Cited by 10 publications

References 6 publications

Microshutter arrays: high contrast programmable field masks for JWST NIRSpec

Microshutter arrays: high contrast programmable field masks for JWST NIRSpec

Cryogenic characterization and testing of magnetically-actuated microshutter arrays for the James Webb Space Telescope

Development of a Microelectromechanical System for Small Satellite Thermal Control

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