NEOWISE Space Infrared Survey
Pasadena CA, USA — NASA’s WISE, a spacecraft that discovered and characterized tens of thousands of asteroids throughout the solar system before being placed in hibernation, will return to service for three more years starting in September, assisting the agency in its effort to identify the population of potentially hazardous near-Earth objects, as well as those suitable for asteroid exploration missions
NEOWISE is the term used to describe the near-Earth object observing capability of the Wide-field Infrared Survey Explorer (WISE) telescope.
WISE uses a 40 cm aperture telescope to observe the entire sky 1.5 times in its 9-month design lifetime. The cryogens used to cool the telescope ran out in November 2010. The infrared wavelength regions are centered at 3.4, 4.6, 12, and 22 microns. The WISE spacecraft is in a nearly polar orbit with the telescope always directed 90 degrees from the sun’s direction.
NEOWISE is an enhancement to the WISE data pipeline that allows new moving objects to be followed up by ground-based telescopes operating in the visible region. These follow-up observations ensure that a NEO’s orbit will be secure and the object will not become lost.
Because dark asteroids re-radiate strongly in the infrared, NEOWISE observations can often provide better estimates for NEO diameters than can optical telescopes.
That is, optical telescopes observe reflected sunlight so they cannot easily tell the difference between a small bright object and large dark object.
The Wide-field Infrared Survey Explorer (WISE) will be revived next month with the goal of discovering and characterizing near-Earth objects (NEOs), space rocks that can be found orbiting within 28 million miles (45 million kilometers) from Earth’s path around the sun.
NASA anticipates WISE will use its 16-inch (40-centimeter) telescope and infrared cameras to discover about 150 previously unknown NEOs and characterize the size, albedo and thermal properties of about 2,000 others — including some which could be candidates for the agency’s recently announced asteroid initiative.
“The WISE mission achieved its mission’s goals and as NEOWISE extended the science even further in its survey of asteroids. NASA is now extending that record of success, which will enhance our ability to find potentially hazardous asteroids, and support the new asteroid initiative,” said John Grunsfeld, NASA’s associate administrator for science in Washington.
“Reactivating WISE is an excellent example of how we are leveraging existing capabilities across the agency to achieve our goal.”
NASA’s asteroid initiative will be the first mission to identify, capture and relocate an asteroid. It represents an unprecedented technological feat that will lead to new scientific discoveries and technological capabilities that will help protect our home planet. The asteroid initiative brings together the best of NASA’s science, technology and human exploration efforts to achieve President Obama’s goal of sending humans to an asteroid by 2025.
Launched in December 2009 to look for the glow of celestial heat sources from asteroids, stars and galaxies, WISE made about 7,500 images every day during its primary mission, from January 2010 to February 2011. As part of a project called NEOWISE, the spacecraft made the most accurate survey to date of NEOs. NASA turned most of WISE’s electronics off when it completed its primary mission.
“The data collected by NEOWISE two years ago have proven to be a gold mine for the discovery and characterization of the NEO population,” said Lindley Johnson, NASA’s NEOWISE program executive in Washington.
“It is important that we accumulate as much of this type of data as possible while the WISE spacecraft remains a viable asset.”
Because asteroids reflect but do not emit visible light, infrared sensors are a powerful tool for discovering, cataloging and understanding the asteroid population. Depending on an object’s reflectivity, or albedo, a small, light-colored space rock can look the same as a big, dark one. As a result, data collected with optical telescopes using visible light can be deceiving.
During 2010, NEOWISE observed about 158,000 rocky bodies out of approximately 600,000 known objects. Discoveries included 21 comets, more than 34,000 asteroids in the main belt between Mars and Jupiter, and 135 near-Earth objects.
The WISE prime mission was to scan the entire celestial sky in infrared light. It captured more than 2.7 million images in multiple infrared wavelengths and cataloged more than 560 million objects in space, ranging from galaxies faraway to asteroids and comets much closer to Earth.
“The team is ready and after a quick checkout, we’re going to hit the ground running,” said Amy Mainzer, NEOWISE principal investigator at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
“NEOWISE not only gives us a better understanding of the asteroids and comets we study directly, but it will help us refine our concepts and mission operation plans for future, space-based near-Earth object cataloging missions.”
JPL manages WISE for NASA’s Science Mission Directorate at the agency’s headquarters in Washington. The mission is part of NASA’s Explorers Program, which NASA’s Goddard Space Flight Center in Greenbelt, Md., manages. The Space Dynamics Laboratory in Logan, Utah, built the science instrument. Ball Aerospace & Technologies Corp. of Boulder, Colo., built the spacecraft. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.
For more information on the asteroid initiative, visit: http://www.nasa.gov/asteroidinitiative .