[meteorite-list] Secondhand Spacecraft Has Firsthand Asteroid Experience (NEOWISE)

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.php?feature=4767

Secondhand Spacecraft Has Firsthand Asteroid Experience
Jet Propulsoin Laboratory
November 11, 2015

The NEOWISE mission hunts for near-Earth objects (NEOs) using the Wide-field 
Infrared Survey Explorer (WISE) spacecraft. Funded by NASA's NEO Observations 
Program, the NEOWISE mission uses images taken by the spacecraft to look 
for asteroids and comets, providing a rich source of measurements of solar 
system objects at infrared wavelengths. These measurements include wavelengths 
that are difficult or impossible to detect directly from the ground.

NEOWISE is one of 54 ongoing projects supported by the NEO Observations 
Program in fiscal year 2015. NASA-funded survey projects have found 98 
percent of the known catalogue of more than 13,000 NEOs. NASA-funded surveys 
are currently finding NEOs at a rate of about 1,500 per year.

The NEOWISE mission uses a repurposed NASA spacecraft to find and characterize 
asteroids. Launched in December 2009, WISE was tasked with documenting 
in infrared light some of the most remote objects in not only our galaxy, 
but our universe. Less than two years later, WISE had done just that, 
scanning the entire sky not once, but twice. From galaxies, to stars, 
to black holes, WISE collected data on over 750 million celestial targets 
of interest. With its mission a complete success after a year of operations, 
WISE was put into hibernation. In December 2014, the space telescope was 
revived with an updated mission and a new name. Its job was to find and 
collect the infrared signatures on some of our closest celestial neighbors 
- asteroids, comets and near-Earth objects. Now led by Principal Investigator 
Amy Mainzer of NASA's Jet Propulsion Laboratory in Pasadena, Calif., the 
mission was named Near-Earth Object WISE, or NEOWISE.

As an infrared telescope, NEOWISE sees the heat emitted from celestial 
bodies. Although it's common to think of objects in space as very cold, 
our sun warms the surfaces of asteroids, making them glow brightly in 
NEOWISE images. Even asteroids as dark as black ink, which can be difficult 
to see against the darkness of space in visible wavelengths, can be spotted 
by NEOWISE's camera.

"Using visible wavelengths of light, it is difficult to tell if an asteroid 
is big and dark, or bright and small, because both combinations reflect 
the same amount of light," said Carrie Nugent, a NEOWISE scientist at 
the Infrared Processing and Analysis Center at California Institute of 
Technology, in Pasadena. "But when you look at an asteroid in the infrared 
with NEOWISE, the amount of infrared light corresponds with how big the 
asteroid is, and with some thermal models on a computer, you can figure 
out how big the asteroids are."

With these thermal models, the NEOWISE team has measured the size and 
brightness of about 20 percent of the known asteroid population. In the 
first year since reactivation, Nugent and the NEOWISE team have made these 
measurements for almost 8,000 asteroids, including 201 near-Earth asteroids.

"When WISE rolled off the assembly line, it was like a shiny new car with 
all the latest technology," said Nugent. "Now it's like that first car 
you get out of school -- more vintage than new and with a lot of miles 
on the odometer. But NEOWISE is giving us great data and experience behind 
the wheel and reminding us every day how powerful infrared space telescopes 
are for finding and studying asteroids."

NEOWISE snaps an infrared image of the sky every 11 seconds from its orbit 
around Earth. Outside of Earth's atmosphere, it always has a clear view 
of the night sky. NEOWISE's orbit was designed so that the telescope never 
sees the sun. Although a person may not like the idea of living in darkness, 
this is perfect for NEOWISE, since too much light would damage its sensitive 
sensors.

Although NEOWISE has been a reliable workhorse operating long past its 
planned lifetime, its mission will eventually come to an end. The spacecraft's 
orbit is changing, and sometime in 2017, engineers estimate it will move 
into too much sunlight to function. However, the team is eyeing a new 
space telescope, one with a little more muscle. NEOWISE Principal Investigator 
Amy Mainzer led a proposal for a new asteroid-hunting spacecraft, the 
Near-Earth Object Camera (NEOCam). Unlike NEOWISE, NEOCam is specifically 
designed to hunt asteroids. NEOCam is one of five Discovery-class proposals 
funded for further study this year by NASA.

"There's so much left to discover when it comes to asteroids," said Nugent. 
"And the NEOWISE mission is a great asset for learning more about our 
closest extraterrestrial neighbors."

More information about the NEOWISE mission is at:

http://neowise.ipac.caltech.edu/

More information about the NEOCam proposal is at:

http://neocam.ipac.caltech.edu/


Media Contact

DC Agle
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011
agle at jpl.nasa.gov 

2015-344