Ingolf Heinrichsen

The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance

The all sky surveys done by the Palomar Observatory Schmidt, the European Southern Observatory Schmidt, and nthe United Kingdom Schmidt, the InfraRed Astronomical Satellite, and the Two Micron All Sky Survey have nproven to be extremely useful tools for astronomy with value that lasts for decades. The Wide-field Infrared nSurvey Explorer (WISE) is mapping the whole sky following its launch on 2009 December 14. WISE began nsurveying the sky on 2010 January 14 and completed its first full coverage of the sky on July 17. The survey nwill continue to cover the sky a second time until the cryogen is exhausted (anticipated in 2010 November). nWISE is achieving 5σ point source sensitivities better than 0.08, 0.11, 1, and 6 mJy in unconfused regions on nthe ecliptic in bands centered at wavelengths of 3.4, 4.6, 12, and 22μm. Sensitivity improves toward the ecliptic npoles due to denser coverage and lower zodiacal background. The angular resolution is 6.1, 6.4, 6.5, and 12.0 at 3.4, 4.6, 12, and 22μm, and the astrometric precision for high signal-to-noise sources is better than 0.15.

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

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.

Preliminary design of the Wide-Field Infrared Survey Explorer (WISE)

The Wide-field Infrared Survey Explorer (WISE), a NASA MIDEX mission, will survey the entire sky in four bands from 3.3 to 23 microns with a sensitivity 1000 times greater than the IRAS survey. The WISE survey will extend the Two Micron All Sky Survey into the thermal infrared and will provide an important catalog for the James Webb Space Telescope. Using 10242 HgCdTe and Si:As arrays at 3.3, 4.7, 12 and 23 microns, WISE will find the most luminous galaxies in the universe, the closest stars to the Sun, and it will detect most of the main belt asteroids larger than 3 km. The single WISE instrument consists of a 40 cm diamond-turned aluminum afocal telescope, a two-stage solid hydrogen cryostat, a scan mirror mechanism, and reimaging optics giving 5 resolution (full-width-half-maximum). The use of dichroics and beamsplitters allows four color images of a 47x47 field of view to be taken every 8.8 seconds, synchronized with the orbital motion to provide total sky coverage with overlap between revolutions. WISE will be placed into a Sun-synchronous polar orbit on a Delta 7320-10 launch vehicle. The WISE survey approach is simple and efficient. The three-axis-stabilized spacecraft rotates at a constant rate while the scan mirror freezes the telescope line of sight during each exposure. WISE is currently in its Preliminary Design Phase, with the mission Preliminary Design Review scheduled for July, 2005. WISE is scheduled to launch in mid 2009; the project web site can be found at www.wise.ssl.berkeley.edu.

Update on the Wide-Field Infrared Survey Explorer (WISE)

The Wide-field Infrared Survey Explorer (WISE), a NASA MIDEX mission, will survey the entire sky in four bands from 3.3 to 23 microns with a sensitivity 1000 times greater than the IRAS survey. The WISE survey will extend the Two Micron All Sky Survey into the thermal infrared and will provide an important catalog for the James Webb Space Telescope. Using 10242 HgCdTe and Si:As arrays at 3.3, 4.7, 12 and 23 microns, WISE will find the most luminous galaxies in the universe, the closest stars to the Sun, and it will detect most of the main belt asteroids larger than 3 km. The single WISE instrument consists of a 40 cm diamond-turned aluminum afocal telescope, a two-stage solid hydrogen cryostat, a scan mirror mechanism, and reimaging optics giving 5 resolution (full-width-half-maximum). The use of dichroics and beamsplitters allows four color images of a 47x47 field of view to be taken every 8.8 seconds, synchronized with the orbital motion to provide total sky coverage with overlap between revolutions. WISE will be placed into a Sun-synchronous polar orbit on a Delta 7320-10 launch vehicle. The WISE survey approach is simple and efficient. The three-axis-stabilized spacecraft rotates at a constant rate while the scan mirror freezes the telescope line of sight during each exposure. WISE has completed its mission Preliminary Design Review and its NASA Confirmation Review, and the project is awaiting confirmation from NASA to proceed to the Critical Design phase. Much of the payload hardware is now complete, and assembly of the payload will occur over the next year. WISE is scheduled to launch in late 2009; the project web site can be found at www.wise.ssl.berkeley.edu.

Managing the Development of the Wide-Field Infrared Survey Explorer Mission

The Wide-field Infrared Survey Explorer (WISE), a NASA Medium-Class Explorer (MIDEX) mission, is surveying the entire sky in four bands from 3.4 to 22 microns with a sensitivity hundreds to hundreds of thousands times better than previous all-sky surveys at these wavelengths. The single WISE instrument consists of a 40 cm three-mirror anastigmatic telescope, a two-stage solid hydrogen cryostat, a scan mirror mechanism, and reimaging optics giving 6 resolution (fullwidth- half-maximum). WISE was placed into a Sun-synchronous polar orbit on a Delta II 7320 launch vehicle on December 14, 2009. NASA selected WISE as a MIDEX in 2002 following a rigorous competitive selection process. To gain further confidence in WISE, NASA extended the development period one year with an option to cancel the mission if certain criteria were not met. MIDEX missions are led by the principal investigator who in this case delegated day-today management to the project manager. With a cost cap and relatively short development schedule, it was essential for all WISE partners to work seamlessly together. This was accomplished with an integrated management team representing all key partners and disciplines. The project was developed on budget and on schedule in spite of the need to surmount significant technical challenges. This paper describes our management approach, key challenges and critical decisions made. Results are described from a programmatic, technical and scientific point of view. Lessons learned are offered for projects of this type.

The mission operations system for Wide-Field Infrared Survey Explorer (WISE)

The goal of the Wide-field Infrared Survey Explorer (WISE) mission is to perform a highly sensitive all-sky survey in 4 wavebands from 3 to 25 μm. Launched on a Delta II rocket into a 500 km Sun-synchronous orbit in June 2009, during its 7 months of operations, WISE will acquire about 50 GBytes of raw science data every day, which will be down-linked via the TDRSS relay satellite system and processed into an astronomical catalogue and image atlas. The WISE mission operations system is being implemented in collaboration between UCLA, JPL and IPAC (Caltech). In this paper we describe the challenges to manage a high data rate, cryogenic, low earth-orbit mission; maintaining safe on-orbit operations, fast anomaly recoveries (mandated by the desire to provide complete sky coverage in a limited lifetime), production and dissemination of high quality science products, given the constraints imposed by funding profiles for small space missions.

Lessions learned in WISE image quality

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.

A payload-centric integration and test approach on the Wide-field Infrared Survey Explorer Mission

NASAs 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.

WISE ground characterization challenges and accomplishments

NASAs 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 mission.

The WISE In-orbit Calibration

The Wide-field Infrared Survey Explorer mission will be executed by an earth-orbiting spacecraft carrying an infrared telescope cooled by a solid hydrogen cryostat. The purpose of the mission is to conduct an allsky survey at infrared wavelengths of 3.3, 4.7, 12 and 23 microns. The 7-month period of on-orbit operations includes one month of in-orbit checkout (IOC) and 6 months of all-sky survey scans from a dawn/dusk sun-synchronous orbit. The 30-day IOC is divided into two parts by the ejection of the telescope aperture cover some two weeks after launch. The first half of the IOC phase is primarily allocated to bus characterization; the latter half will be dedicated to cover-off instrument calibrations. In this discussion, we provide a description of the instrument calibrations to be conducted during IOC and how these plans will be carried out efficiently during the limited checkout period. The on-orbit instrument checkout is an extension of the overall WISE calibration plan. The duration of onboard calibration activities is limited by the lifetime of the cryogen and the need to begin the survey quickly. Key activities were selected because they must be done and can only be done in flight.