[meteorite-list] NASA'S Neowise Completes Scan For Asteroids And Comets

[Ron Baalke]

Feb. 1, 2011

Trent Perrotto/Dwayne Brown 
Headquarters, Washington                                
202-358-5241/1726 
trent.j.perrotto at nasa.gov 
dwayne.c.brown at nasa.gov 

Whitney Clavin 
Jet Propulsion Laboratory, Pasadena, Calif. 
818-354-4673 
whitney.clavin at jpl.nasa.gov 

RELEASE: 11-029

NASA'S NEOWISE COMPLETES SCAN FOR ASTEROIDS AND COMETS

WASHINGTON -- NASA's NEOWISE mission has completed its survey of small 
bodies, asteroids and comets, in our solar system. The mission's 
discoveries of previously unknown objects include 20 comets, more 
than 33,000 asteroids in the main belt between Mars and Jupiter, and 
134 near-Earth objects (NEOs). The NEOs are asteroids and comets with 
orbits that come within 28 million miles of Earth's path around the 
sun. 

NEOWISE is an enhancement of the Wide-field Infrared Survey Explorer, 
or WISE, mission that launched in December 2009. WISE scanned the 
entire celestial sky in infrared light about 1.5 times. It captured 
more than 2.7 million images of objects in space, ranging from 
faraway galaxies to asteroids and comets close to Earth. 

In early October 2010, after completing its prime science mission, the 
spacecraft ran out of frozen coolant that keeps its instrumentation 
cold. However, two of its four infrared cameras remained operational. 
These two channels were still useful for asteroid hunting, so NASA 
extended the NEOWISE portion of the WISE mission by four months, with 
the primary purpose of hunting for more asteroids and comets, and to 
finish one complete scan of the main asteroid belt. 

"Even just one year of observations from the NEOWISE project has 
significantly increased our catalog of data on NEOs and the other 
small bodies of the solar systems," said Lindley Johnson, NASA's 
program executive for the NEO Observation Program. 
Now that NEOWISE has successfully completed a full sweep of the main 
asteroid belt, the WISE spacecraft will go into hibernation mode and 
remain in polar orbit around the Earth, where it could be called back 
into service in the future. 

In addition to discovering new asteroids and comets, NEOWISE also 
confirmed the presence of objects in the main belt that already had 
been detected. In just one year, it observed about 153,000 rocky 
bodies out of approximately 500,000 known objects. Those include the 
33,000 that NEOWISE discovered. 

NEOWISE also observed known objects closer and farther to us than the 
main belt, including roughly 2,000 asteroids that orbit along with 
Jupiter, hundreds of NEOs and more than 100 comets. 

These observations will be key to determining the objects' sizes and 
compositions. Visible-light data alone reveals how much sunlight 
reflects off an asteroid, whereas infrared data is much more directly 
related to the object's size. By combining visible and infrared 
measurements, astronomers also can learn about the compositions of 
the rocky bodies -- for example, whether they are solid or crumbly. 
The findings will lead to a much-improved picture of the various 
asteroid populations. 

NEOWISE took longer to survey the whole asteroid belt than WISE took 
to scan the entire sky because most of the asteroids are moving in 
the same direction around the sun as the spacecraft moves while it 
orbits the Earth. The spacecraft field of view had to catch up to, 
and lap, the movement of the asteroids in order to see them all. 

"You can think of Earth and the asteroids as racehorses moving along 
in a track," said Amy Mainzer, the principal investigator of NEOWISE 
at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We're moving 
along together around the sun, but the main belt asteroids are like 
horses on the outer part of the track. They take longer to orbit than 
us, so we eventually lap them." 

NEOWISE data on the asteroid and comet orbits are catalogued at the 
NASA-funded International Astronomical Union's Minor Planet Center, a 
clearinghouse for information about all solar system bodies at the 
Smithsonian Astrophysical Observatory in Cambridge, Mass. The science 
team is analyzing the infrared observations now and will publish new 
findings in the coming months. 

When combined with WISE observations, NEOWISE data will aid in the 
discovery of the closest dim stars, called brown dwarfs. These 
observations have the potential to reveal a brown dwarf even closer 
to us than our closest known star, Proxima Centauri, if such an 
object does exist. Likewise, if there is a hidden gas-giant planet in 
the outer reaches of our solar system, data from WISE and NEO-WISE 
could detect it. 

The first batch of observations from the WISE mission will be 
available to the public and astronomical community in April. 
"WISE has unearthed a mother lode of amazing sources, and we're having 
a great time figuring out their nature," said Edward (Ned) Wright, 
the principal investigator of WISE at UCLA. 

JPL manages WISE for NASA's Science Mission Directorate at the 
agency's headquarters in Washington. The mission was competitively 
selected under 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, and 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. JPL manages NEOWISE for NASA's Planetary 
Sciences Division. The mission's data processing also takes place at 
the Infrared Processing and Analysis Center. 

For more information about WISE, visit: 

http://www.nasa.gov/wise 
	
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