Overview of Lockheed Martin cryocoolers

WISE is a NASA MIDEX mission to survey the entire sky in four bands from 3 to 25 microns with sensitivity about 500 times greater than the IRAS survey. WISE will find the most luminous galaxies in the universe, find the closest stars to the Sun, and detect most of the main belt asteroids larger than 3 km. WISE launch is scheduled in November, 2009 on a Delta 7320-10 to a 525 km Sun-synchronous polar orbit. This paper gives an overview of WISE including development status and management approach. WISE flight system design is single string with selected redundancy and graceful degradation. Wherever possible, design heritage from prior missions is pursued and properly reviewed to reduce development time and cost. Further risk reduction is achieved since the WISE spacecraft has no deployable mechanisms and no propulsion. Nonetheless, a complex space mission with a sophisticated cryogenic IR telescope such as WISE demands a partnership of multiple organizations in government research, academia, and industry. With a cost cap and relatively short development schedule, it is essential for all WISE partners to work seamlessly together. This is accomplished by a single management team representing all key partners and disciplines in science, systems engineering, mission assurance, project and contract management. WISE uses a variety of management tools including frequent team interaction, schedule, milestone and critical path analysis, risk analysis, reliability analysis, earned value analysis, configuration management, and management of schedule and budget reserves. After a successful mission critical design review in June, 2007, WISE has completed building most of the flight hardware, and started integration and test within payload and spacecraft.

Development of the Wide-field Infrared Survey Explorer (WISE) mission

The Wide Field Infrared Survey Explorer is a NASA Medium Class Explorer mission to perform an all-sky survey in four infrared wavelength bands. The science payload is a cryogenically cooled infrared telescope with four 1024 2 infrared focal plane arrays covering from 2.8 to 26 μm. Advances in focal plane technology and a large aperture cryogenic telescope allow an all-sky survey to be performed with high sensitivity and resolution. An efficient survey is obtained using a cryogenic scan mirror to freeze the field of view on the sky over the 9.9-second frame integration time. Mercury cadmium telluride (MCT) detectors, cooled to 32 K, are used for the two midwave channels (3.3 μm and 4.6 μm), and Si:As detectors, cooled to < 8.3 K, are used for the two long wavelength channels (12 μm and 23 μm). Cooling is provided by a two-stage solid hydrogen cryostat which provides temperatures < 17 K and < 8.3 K at the telescope and Si:As focal planes, respectively. The science payload supports operations on orbit for the seven-month baseline mission with a goal to support a 13-month extended mission, if possible. The payload recently passed CDR and is being fabricated. This paper provides a payload overview and discusses instrument requirements and performance.

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Wide-field infrared survey explorer science payload update

The Wide Field Infrared Survey Explorer is a NASA Medium Class Explorer mission to perform and all-survey in four infrared wavelength bands. The science payload is a cryogenically cooled infrared telescope with four 1024 2 infrared focal plane arrays covering from 2.8 to 26 microns. Advances in focal plane technology and a large aperture allow an all-sky survey to be performed with high sensitivity and resolution. Mercury cadmium telluride (MCT) detectors, cooled to 32 K, are used for the two midwave channels, and Si:As detectors, cooled to < 8.3 K, are used for the two long wavelength channels. Cooling for the payload is provided by a two-stage solid hydrogen cryostat providing temperatures <17K and < 8.3K at the telescope and Si:As focal planes, respectively. The science payload supports operations on orbit for the seven month baseline mission with a goal to support a 13 month extended mission if available. This paper provides a payload overview and discusses instrument requirements and performance.

Wide-field Infrared Survey Explorer science payload overview

Wide-field Infrared Survey Explorer Science Payload Update

The Wide-Field Infrared Survey Explorer (WISE) is a MIDEX mission that is being developed by the Jet Propulsion Laboratory (JPL) to address several of NASA's Astronomical Search of Origins (ASO) objectives. The WISE instrument, developed by the Space Dynamics Laboratory (SDL), includes a cryogenically cooled telescope (at < 13K) and four focal plane assemblies (2 at 7.6K, 2 at 32K). Cooling of the instrument is accomplished by a dual-stage solid hydrogen cryostat that is developed by the Lockheed Martin Advanced Technology Center (LM-ATC). This paper provides a combined overview of the WISE cryostat design and thermal support system.

Joe Cannon

Papers

WISE solid hydrogen cryostat design overview