Scott Schick

Wide-field Infrared Survey Explorer science payload update

The Wide Field Infrared Survey Explorer is a NASA Medium Class Explorer mission to perform a high-sensitivity, high resolution, all-sky survey in four infrared wavelength bands. The science payload is a 40 cm aperture cryogenically cooled infrared telescope with four 10242 infrared focal plane arrays covering from 2.8 to 26 μm. Mercury cadmium telluride (MCT) detectors are used for the 3.3 μm and 4.6 μm channels, and Si:As detectors are used for the 12 μm and 23 μm wavelength channels. A cryogenic scan mirror freezes the field of view on the sky over the 9.9-second frame integration time. A two-stage solid hydrogen cryostat provides cooling to temperatures less than 17 K and 8.3 K at the telescope and Si:As focal planes, respectively. The science payload collects continuous data on orbit for the seven-month baseline mission with a goal to support a year-long mission, if possible. As of the writing of this paper, the payload subassemblies are complete, and the payload has begun integration and test. This paper provides a payload overview and discusses instrument status and performance.

WISE solid hydrogen cryostat design overview

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 NASAs 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.

Wide-field Infrared Survey Explorer science payload overview

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 10242 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.

Design and performance analysis of the wide-field infrared explorer H2/H2 cryostat

The wide-field infrared explorer (WIRE) is a small explorer (SMEX) mission that will fly in the fall of 1998. The WIRE mission proposes to conduct a 4-month survey of more than 100 degree2 of sky using 12- and 25-micrometers detectors. The instrument requires cryogenic cooling of its focal planes and telescope in order to achieve the required performance sensitivity. In addition, because of the SMEX nature of the experiment, the mass of the cryostat must be less than 60 kg. The most mass efficient system meeting the lifetime requirement was determined to be a dual stage H2/H2 cryostat. The focal planes are conductively cooled by the primary H2 while the telescope is cooled by the secondary H2. The secondary H2 also protects the primary H2 by intercepting the parasitic heat loads. This paper describes the design and performance of the H2/H2 cryostat.

WISE CRYOGENIC SUPPORT SYSTEM DESIGN OVERVIEW AND BUILD STATUS

The Wide-Field Infrared Survey Explorer (WISE) is a NASA MIDEX mission that is being developed by the Jet Propulsion Laboratory (JPL) to address several of NASAs Astronomical Search of Origins (ASO) objectives. The WISE instrument, developed by the Space Dynamics Laboratory (SDL), is a 40-cm cryogenically-cooled telescope operating at <17K, with four infrared focal planes, two of which operate at 7.8 K and two of which operate at 32 K. Cooling of the instrument is accomplished by a dual-stage solid hydrogen cryostat that is developed by the Lockheed Martin Advanced Technology Center (LMATC). The drivers for the cryogenic support system design are the 7-month lifetime, temperature requirements, and limiting heat loads into the open aperture.This paper provides an overview of the WISE cryogenic support system design and a status of the flight system build.

Development of hydrogen-filling techniques for the SPIRIT III cryostat

SPIRIT III, the primary sensor to be flown aboard the BMDO midcourse space experiment, will be cooled using a 9 K solid-hydrogen cryostat. Laboratory cold tests of SPIRIT III have relied on helium as the cryogen because of the inherent risks associated with hydrogen.

Wide-field Infrared Survey Explorer cryogenic support system lessons learned

The Wide-Field Infrared Survey Explorer (WISE) is a JPL-managed MIDEX mission to perform an infrared all-sky survey. The WISE instrument, developed by the Space Dynamics Laboratory (SDL), is a 40-cm cryogenically-cooled telescope which includes a cryogenic scan mirror and four infrared focal planes (2-HgCdTe, 2-Si:As). Cooling the instrument to the desired temperatures is accomplished by a two-stage, solid hydrogen cryostat, provided by Lockheed Martin Advanced Technology Center (LMATC). Required temperatures for the instrument optics and Si:As focal planes are <13 K and <7.6 K respectively. To reduce heat loads, the vacuum shell is isolated from the spacecraft bus via composite struts and radiatively cooled to <200 K. The telescope aperture is protected from on-orbit environmental loads via a two-stage radiatively cooled aperture shade. WISE was successfully launched into a 530 km, polar orbit on December 14, 2009, beginning a 10-month mission to survey the entire sky in the infrared.

Wide-field Infrared Survey Explorer cryogenic support system status and thermal test results

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 NASAs Astronomical Search of Origins (ASO) objectives. Space Dynamics Laboratory/ Utah State University is providing the cryogenically cooled infrared instrument. Cooling for the instrument optics and focal planes is provided by a dual-stage solid hydrogen cryostat. Driving requirements for the cryogenic subsystem are: a seven-month lifetime and operating temperatures of less than 17 K for the optics, 32 K for the HgCdTe focal planes, and 7.8 K for the Si:As focal planes. This paper provides an overview of the dual-stage hydrogen cryogenic subsystem status and discusses the results of the thermal performance testing.

Status and design concepts for the hydrogen on-orbit storage and supply experiment

This paper studies concepts for the Hydrogen On-Orbit Storage And Supply Experiment (HOSS). HOSS is a space flight experiment whose objectives are: Show stable gas supply for storage and direct gain solar-thermal thruster designs; and evaluate and compare low-g performance of active and passive pressure control via a thermodynamic vent system (TVS) suitable for solar-thermal upper stages. This paper shows that the necessary experimental equipment for HOSS can be accommodated in a small hydrogen dewar of 36 to 80 liter. Thermal designs for these dewars which meet the on-orbit storage requirements can be achieved. Furthermore ground hold insulation and shielding concepts are achieved which enable storing initially subcooled liquid hydrogen in these small dewars without venting in excess of 144 hours.

Hydrogen on-orbit storage and supply (HOSS) thermal design and analysis

This paper describes the thermal design and analysis of the HOSS (Hydrogen On-Orbit Storage and Supply) liquid hydrogen dewar. This task is being carried out by the Space Dynamics Laboratory at Utah State University under contract from NASA Lewis Research Center. The vacuum jacketed 80-liter dewar is designed for a mission life greater than 30 days. The design uses concentric G-10 fiberglass support tubes and multilayer insulation to thermally isolate the hydrogen tank. Heat load trade off studies were performed based on the support tube thickness, plumbing size, and vacuum shell temperature. The dewar employs a liquid nitrogen cooled shield to provide a non-venting ground hold capability of more than 96 hours for launch preparation. Analysis has shown that a greater than 30 day mission is feasible even with a mechanically robust design capable of withstanding most launch environments.