The Wide-Field Infrared Survey Explorer (WISE) mission launched in December of 2009 is a true success story. The
mission is performing beyond expectations on-orbit and maintained cost and schedule throughout. How does such a
thing happen? A team constantly focused on mission success is a key factor. Mission success is more than a program
meeting its ultimate science goals; it is also meeting schedule and cost goals to avoid cancellation. The WISE program
can attribute some of its success in achieving the image quality needed to meet science goals to lessons learned along the
way. A requirement was missed in early decomposition, the absence of which would have adversely affected end-to-end
system image quality. Fortunately, the ability of the cross-organizational team to focus on fixing the problem without
pointing fingers or waiting for paperwork was crucial in achieving a timely solution. Asking layman questions early in
the program could have revealed requirement flowdown misunderstandings between spacecraft control stability and
image processing needs. Such is the lesson learned with the WISE spacecraft Attitude Determination & Control
Subsystem (ADCS) jitter control and the image data reductions needs. Spacecraft motion can affect image quality in
numerous ways. Something as seemingly benign as different terminology being used by teammates in separate groups
working on data reduction, spacecraft ADCS, the instrument, mission operations, and the science proved to be a risk to
system image quality. While the spacecraft was meeting the allocated jitter requirement , the drift rate variation need was
not being met. This missing need was noticed about a year before launch and with a dedicated team effort, an adjustment
was made to the spacecraft ADCS control. WISE is meeting all image quality requirements on-orbit thanks to a diligent
team noticing something was missing before it was too late and applying their best effort to find a solution.
NASA's Wide Field Infrared Survey Explorer (WISE), which launched in December 2009, is currently producing an allsky
survey in the mid-infrared (2.8 - 26 microns) with far greater sensitivity and resolution than any previous IR survey
mission. The ongoing on-orbit calibration of the instrument is performed at the Wise Science Data Center (WSDC), but
several of the calibration parameters of interest were best measured on the ground, and have been maintained as part of
the on-orbit calibration process.
The Utah State University Space Dynamics Laboratory (SDL) built the science payload, and performed a series of
ground characterization tests prior to launch. A challenge in a MIDEX mission such as WISE is to balance the various
program demands to perform a thorough ground calibration within schedule and budget constraints, while also
demonstrating compliance with formal flow-down requirements, and simultaneously verifying that performance has not
been degraded during late-program environmental testing. These activities are not always entirely compatible. This
paper presents an assessment of ground characterization challenges and solutions that contributed to a successful WISE
NASA's Wide-field Infrared Survey Explorer (WISE) mission was successfully launched on December 14, 2009. All
spacecraft subsystems and the single instrument consisting of four imaging bands from 3.4 to 22 microns, a 40 cm afocal
telescope, reimaging optics, and a two-stage solid hydrogen cryostat have performed nominally on orbit, enabling the
trouble-free survey of the entire infrared sky. Among the many factors that contributed to the WISE post-launch success
is the thorough pre-launch system integration and test (I&T) approach tailored to the cryogenic payload. The simple and
straightforward interfaces between the spacecraft and the payload allowed the payload to be fully tested prior to
integration with the spacecraft. A payload high-fidelity thermal, mass and dynamic simulator allowed the spacecraft I&T
to proceed independently through the system-level thermal vacuum test and random vibration test. A payload electrical
simulator, a high-rate data processor and a science data ingest processor enabled very early end-to-end data flow and
radio-frequency testing using engineering model payload electronics and spacecraft avionics, which allowed engineers to
identify and fix developmental issues prior to building flight electronics. This paper describes in detail the WISE I&T
approach, its benefits, challenges encountered and lessons learned.
The design, fabrication and testing of the BeamSplitter Assembly (BSA) of the Wide-field Infrared Survey Explorer
(WISE) instrument are discussed in the paper. The BSA splits the WISE telescope optical output beam into 4 spectral
wavelength bands: 2.8-3.8, 4.1-5.2, 7.5-16.5, and 20-26 μm. The BSA also provides focus adjustments to focus the
WISE instrument prior to launch. The methods used to focus WISE are also discussed in this paper. Funding for and
management of the WISE program were provided by the NASA Jet Propulsion Laboratory.
The Wide Field Infrared Survey Explorer is a NASA Medium Class Explorer mission which launched in December,
2009 to perform an all-sky survey in four infrared wavelength bands. The science payload is a cryogenically cooled
infrared telescope with four 1024x1024 infrared focal plane arrays covering the wavelength range from 2.6 to 26 μm.
The survey has been highly successful, with millions of images collected, and nearly daily discoveries of previously
unknown astronomical objects. The WISE science payload was designed, built, and characterized by the Space
Dynamics Laboratory at Utah State University.
This paper provides a brief overview of the WISE science payload and its on-orbit performance and describes lessons
learned from managing the design, fabrication, testing, and operation of a state-of-the-art electro-optical payload.
The Wide-field Infrared Survey Explorer (WISE), launched on December 14, 2009, is a NASA-funded Explorer mission
that is providing an all-sky survey in the mid-infrared with far greater sensitivity and resolution than any previous IR
survey mission. The WISE science payload is a cryogenically cooled infrared telescope with four 1024x1024 infrared
focal plane arrays covering from 2.8 to 26 μm, which was designed, fabricated, and characterized by Utah State
University's Space Dynamics Laboratory. Pre-launch charaterization included measuring focus, repeatability, response
non-linearity, saturation, latency, absolute response, flatfield, point response function, scanner linearity, and relative
spectral response. We will provide a brief overview of the payload, discuss the overall characterization approach, review
several pre-launch characterization methods in detail, and present selected results from ground characterization and early
The Wide-field Infrared Survey Explorer (WISE), launched in December 2009, is a NASA-funded Explorer mission that
is providing an all-sky survey in the mid-infrared with far greater sensitivity and resolution than any previous IR survey
mission. The Utah State University Space Dynamics Laboratory designed, fabricated, and characterized the science
payload, which is a cryogenically cooled infrared telescope with four 1024x1024 infrared focal plane arrays covering
from 2.8 to 26 μm. Pre-launch characterization included measuring focus, image quality, repeatability, response nonlinearity,
saturation, latency, absolute response, flatfield, point response function, scanner linearity, and relative spectral
response. This paper provides a brief overview of the payload, discusses pre-launch characterization methods, and
presents key performance results from ground characterization and early on-orbit performance.
On December 14, 2009 NASA launched the Wide-field Infrared Survey Explorer (WISE), a NASA MIDEX mission
within the Explorers program that is currently performing an all-sky survey in four infrared bands. L-3 Integrated
Optical Systems/SSG designed, built, and tested the telescope, scanner, and aft imaging optical system for WISE under
contract to the Space Dynamics Laboratory. Hardware and test results for those subsystems are presented, as well as an
on-orbit status of their imaging performance. The WISE payload includes a 40 cm afocal telescope, a scan mirror for
back-scan during integration, and an aft optics imager assembly. All modules operate below 17 Kelvin. The allreflective
system uses aluminum mirrors and metering structures. The afocal telescope provides distortion control to
better than two parts in a thousand to prevent image blur during internal scanning. The one-axis scan mirror at the exit
pupil scans the detectors' field-of-view across the telescope field-of-regard, countering the orbital motion and freezing
the line of sight during the multi-second exposure period. The five-mirror imaging optics module follows the scan
mirror and feeds dichroic beamsplitters that separate the energy into four channels between 2.8 and 26 microns. Once
initial on-orbit checkout and calibration was completed, WISE began a 6-month mission performing an all-sky survey in
the four infrared bands, which is over 80% complete as of June 2010.
The Wide-field Infrared Survey Explorer is a NASA Midex mission launching in late 2009 that will survey the entire
sky at 3.3, 4.7, 12, and 23 microns (PI: Ned Wright, UCLA). Its primary scientific goals are to find the nearest stars
(actually most likely to be brown dwarfs) and the most luminous galaxies in the universe. WISE uses three dichroic
beamsplitters to take simultaneous images in all four bands using four 1024×1024 detector arrays. The 3.3 and 4.7
micron channels use HgCdTe arrays, and the 12 and 23 micron bands employ Si:As arrays. In order to make a
1024×1024 Si:As array, a new multiplexer had to be designed and produced. The HgCdTe arrays were developed by
Teledyne Imaging Systems, and the Si:As array were made by DRS.
All four flight arrays have been delivered to the WISE payload contractor, Space Dynamics Laboratory. We present
initial ground-based characterization results for the WISE arrays, including measurements of read noise, dark current,
flat field and latent image performance, etc. These characterization data will be useful in producing the final WISE data
product, an all-sky image atlas and source catalog.
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.
DRS Sensors & Targeting Systems, under contract to the Space Dynamics Laboratory of Utah State University, is
providing the focal plane detector system for NASA's Wide-field Infrared Survey Explorer (WISE). The focal plane
detector system consists of two mercury cadmium telluride (MCT) focal plane module assemblies (FPMAs), two arsenic
doped silicon (Si:As) Blocked Impurity Band (BIB) FPMAs, electronics to drive the FPMAs and report digital data from
them, and the cryogenic and ambient temperature cabling that connect the FPMAs and electronics. The MCT and Si:As
BIB focal plane arrays (FPAs) utilized in the WISE FPMAs are both megapixel class indium-bump hybridized devices
fabricated by Teledyne Imaging Systems and DRS Sensors & Targeting Systems, respectively. This paper reports
performance of the WISE Si:As BIB FPAs that are used for the WISE 12- and 23-μm wavelength bands.
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 10242 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.
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.
The Wide-Field Infrared Explorer (WIRE) is a small cryogenic spaceborne infrared telescope being readied for launch in September 1998 as the fifth of NASA's Small Explorers. WIRE utilizes two 128 X 128 Si:As Focal Plane Arrays (FPAs) produced by Boeing North American with a 30 cm diameter Ritchey Cretien diamond turned mirror system. This mission takes advantage of recent advances in infrared array detector technology to provide a large sensitivity gain over previously flown missions. Two broad pass bands are defined for a deep pointed survey to search for protogalaxies and to study the evolution of starburst galaxies. The Space Dynamics Laboratory at Utah State University (SDL/USU) used the multifunction infrared calibrator and other special purpose cryogenic equipment to perform a ground characterization of the WIRE instrument. The focus was verified cold with two independent measurements. Both in-band and out-of-band Relative Spectral Response measurements were made; some sensitivity to temperature, bias voltage, and location on the long wavelength focal plane array were found. Dark current and dark noise measurements are also reported.
This paper describes the goniometric calibration of the spatial RI imaging telescope (SPIRIT) III. The SPIRIT III radiometer is the primary instrument aboard the Midcourse Space Experiment (MSX) satellite which was launched on 24 April, 1996. The sensor consists of an off-axis reimaging telescope with a six-band scanning radiometer that covers the spectrum from midwave IR to longwave IR. The radiometer has five arsenic-doped silicon focal plane detector arrays which operate at temperatures between 11 and 13 K. These arrays consists of 8 by 192 pixels, with an angular separation between adjacent pixels of approximately 90 (mu) rad. A single axis scan mirror can either remain fixed, or operate at a constant 0.46 deg/sec scan rate to give programmable fields of regard of 1 by 0.75, 1 by 1.5, and 1 by 3 degrees. The calibration, which is based on a physical model of the sensor, uses ground and on-orbit observations to determine and separate effects of scan-mirror encoder non-linearity, scan-mirror readout timing and angular velocity, detector readout timing, array coalignment, and optical distortion. This paper describes the calibration methodology and gives results using observations of stellar sources acquired during on-orbit operations.
The Wide-Field IR Explorer (WIRE) is a small spaceborne cryogenic IR telescope being readied for launch in September 1998. Part of NASA's Small Explorer program, WIRE will carry out a deep pointed survey in broad 24 and 12 micron passbands designed primarily to study the evolution of starburst galaxies and to search for protogalaxies. The strategy for the WIRE survey and its stare-and-dither technique for building up long exposure times are described. An overview of the WIRE instrument is presented, with emphasis on the results of ground characterization and expected on-orbit performance of the WIRE optics and the Si:As focal plane arrays. The result of the ground characterization demonstrate that WIRE will meet or exceed the requirements for its science objectives. A brief overview is given of the primary and additional science that will be enabled by WIRE.
This paper describes background removal, point source detection, and position and irradiance extraction data processing algorithms that have been developed for the Spatial Infrared Imaging Telescope (SPIRIT) III design. The SPIRIT III sensor is the primary instrument on the Midcourse Space Experiment (MSX) satellite and is scheduled for launch in early 1996. The sensor consists of an off-axis reimaging telescope, and, among other instruments, a six-band scanning radiometer that covers the spectrum from midwave infrared to longwave infrared. The radiometer has five arsenic-doped silicon (Si:As) focal plane detector arrays with 8 X 192 pixels. The angular separation between adjacent pixels is 90 (mu) rad. A single axis scan mirror can operate at a constant 0.46 deg/sec scan rate to give programmable fields of regard of 1 X 0.75, 1 X 1.5, and 1 X 3 degrees or can remain fixed. Scanned images are non-uniformly sampled because of non-linear scan mirror motion, array misalignment, optical distortion, detector readout ordering, and satellite rotation. In addition, three of the five arrays contain multiple cross-scan aligned columns of pixels that five scanned images that have spatially overlapping in- scan data. Algorithms for processing data sampled on a uniform grid, such as data obtained from a CCD array, are enhanced and applied to the SPIRIT III radiometer where scanned images are non-uniformly sampled and have spatially overlapping data. The performance of these algorithms are evaluated with point source data acquired during ground measurements.
The Midcourse Space Experiment (MSX) satellite is scheduled for launch in early 1996. The Spatial Infrared Imaging Telescope (SPIRIT) III sensor, the primary instrument of MSX, covers the spectrum from the midwave infrared to the longwave infrared. The SPIRIT III instrument is cryogenically cooled and consists of an interferometer and a five-band scanning radiometer with a spatial resolution of 90 (mu) rad. This paper describes the unique algorithms and software implementation developed to support the SPIRIT III radiometer. The algorithms for converting raw radiometer counts to calibrated counts and then to engineering units are described. The standard process (raw counts to corrected counts) consists of dark offset correction, linearity correction, integration mode normalization, non-uniformity correction, field of regard non-uniformity correction, and bad pixel processing. The algorithm to convert corrected counts to point source engineering units consist of pixel position tagging (non-uniform grid), color coalignment, distortion correction, background subtraction, correction for spacecraft attitude, and position and amplitude determination. The algorithms implemented in the software must produce goniometric estimates to within 5 (mu) rad (0.05 pixel) and radiometric results to within 1 percent. The results of the algorithms are demonstrated in this paper.