NASA's Wide-field Infrared Survey Explorer (WISE) spacecraft has been brought out of hibernation and has resumed surveying the sky at 3.4 and 4.6 um. The scientific objectives of the NEOWISE reactivation mission are to detect, track, and characterize near-Earth asteroids and comets. The search for minor planets resumed on December 23, 2013, and the first new near-Earth object (NEO) was discovered six days later. As an infrared survey, NEOWISE detects asteroids based on their thermal emission and is equally sensitive to high and low albedo objects; consequently, NEOWISE-discovered NEOs tend to be large and dark. Over the course of its three-year mission, NEOWISE will determine radiometrically-derived diameters and albedos for approximately 2000 NEOs and tens of thousands of Main Belt asteroids. The 32 months of hibernation have had no significant effect on the mission's performance. Image quality, sensitivity, photometric and astrometric accuracy, completeness, and the rate of minor planet detections are all essentially unchanged from the prime mission's post-cryogenic phase.

The all sky surveys done by the Palomar Observatory Schmidt, the European Southern Observatory Schmidt, and the United Kingdom Schmidt, the InfraRed Astronomical Satellite, and the Two Micron All Sky Survey have proven to be extremely useful tools for astronomy with value that lasts for decades. The Wide-field Infrared Survey Explorer (WISE) is mapping the whole sky following its launch on 2009 December 14. WISE began surveying the sky on 2010 January 14 and completed its first full coverage of the sky on July 17. The survey will continue to cover the sky a second time until the cryogen is exhausted (anticipated in 2010 November). WISE is achieving 5 sigma point source sensitivities better than 0.08, 0.11, 1, and 6 mJy in unconfused regions on the ecliptic in bands centered at wavelengths of 3.4, 4.6, 12, and 22 mu m. Sensitivity improves toward the ecliptic poles 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 22 mu m, and the astrometric precision for high signal-to-noise sources is better than 0 ''.15.

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.

WISE, the Wide Field Infrared Survey Explorer, is scheduled for launch in June 2009. The mission operations system for WISE requires a software modeling tool to help plan, integrate and simulate all spacecraft pointing and verify that no attitude constraints are violated. In the course of developing the requirements for this tool, an investigation was conducted into the design of similar tools for other space-based telescopes. This paper summarizes the ground software and processes used to plan and validate pointing for a selection of space telescopes; with this information as background, the design for WISE is presented.