[meteorite-list] Canadian Asteroid-Hunting Satellite to Launch on Feb 25 (NEOSSat)

[Ron Baalke]

http://www.spaceflightnow.com/news/n1302/23neossat/#.USph1Bgo26A

Canadian asteroid-hunting satellite to launch Monday
BY STEPHEN CLARK
SPACEFLIGHT NOW
February 23, 2013

A small satellite built in Canada is stowed for liftoff from India on Monday on a 
mission to spot asteroids, especially the kind posing a hazard to Earth.
 
The Near-Earth Object Surveillance Satellite, or NEOSSat, is the first spacecraft 
designed for asteroid detection, and its launch will come barely one week after 
a meteor exploded over Russia.

The Russian meteor, which blasted out windows and injured more 
than 1,000 people, occurred the same day a larger 150-foot-wide asteroid 
narrowly missed Earth. Scientists determined the two events were not related.

The launch of NEOSSat was supposed to be in 2010, but a series of delays pushed 
back the mission until 2013. Now the launch is occurring at a time when 
asteroids have reached the pinnacle of public consciousness.

"It just happened that way. It's just the effect of coincidence," said Alan 
Hildebrand, a professor at the University of Calgary and lead scientist for 
NEOSSat's asteroid search mission.

NEOSSat will launch Monday with six other satellites 
on India's Polar Satellite Launch Vehicle. The PSLV will lift off at 1226 
GMT (7:26 a.m. EST), or 5:56 p.m. local time at the Satish Dhawan Space 
Center on Sriharikota Island, India's primary launch site on the country's 
east coast.

The rocket's other passengers include a French-Indian ocean 
research satellite, a Canadian military satellite, two Canadian-Austrian 
nanosatellites with tiny telescopes, a small British satellite powered 
by a smartphone, and a CubeSat built by students in Denmark.

The four-stage rocket, flying in a stripped-down "core-alone" configuration 
without strap-on boosters, will release all the satellites in a 487-mile-high 
sun-synchronous orbit within 22 minutes after liftoff, according to the Indian 
Space Research Organization.

NEOSSat is small - only about the size and shape of a suitcase. 
It weighs about 160 pounds, and the satellite has a cylindrical telescope 
sticking out of one side.

The telescope is also modest by professional standards. It measures 5.9 inches 
in diameter, but it is sensitive enough to spot objects as faint as magnitude 20.

Jointly funded by the Canadian Space Agency and Defence Research and Development 
Canada, a research arm of the Canadian military, NEOSSat will collect up to 288 
images per day, ultimately covering the entire sky.

Half of NEOSSat's observing time will be devoted to asteroid-hunting, and Canadian 
military researchers will use the rest of the time experimenting with the craft's 
ability to spot and track other satellites in high-altitude Earth orbits.

Equipped with a precise pointing system to keep the images steady, NEOSSat will 
resolve satellites and asteroids as they dart across a matrix of stars. 
Each NEOSSat image will have an exposure time of 100 seconds, according 
to scientists.

"We believe that, if successful, this project will deliver 
great science," said Guennadi Kroupnik, director of satellite communications 
and space environment projects at the Canadian Space Agency. "It will 
help to discover and to monitor asteroids and comets in the inner solar 
system, where there are a lot of challenges for observations from the 
ground."

Besides making tangible discoveries, NEOSSat is a pathfinder 
for future asteroid-hunting telescopes. It is the first space mission 
specifically designed to search for asteroids, according to Canadian officials.

The B612 Foundation, a non-profit organization, is raising funds in hopes 
of building and launching a more ambitious telescope to fly in the inner 
solar system and look away from the sun toward Earth, catching the glint 
of asteroids from a more favorable perspective.

Space missions can observe the sky 24 hours a day, dodging the day-night 
cycle and inclement weather inhibiting ground telescopes.

"Being able to predict, well ahead of time, potential close encounters is a 
very important part of space surveillance, and we hope to contribute to that 
very important objective," Kroupnik said in an interview.

NASA's Wide-Field Infrared Survey Explorer, originally 
built to observe stars and galaxies, scanned the sky for asteroids in 
2010 and 2011, finding nearly 130 new near-Earth asteroids. The WISE satellite 
carried a larger telescope than NEOSSat, and its infrared detectors made 
the telescope more sensitive to dark-colored asteroids.

NEOSSat's advantage lies in its ability to sweep through slivers of the sky 
close to the sun, allowing the telescope to pick out Earth-crossing asteroids 
on trajectories shadowing or leading our planet on its path around the sun.
 
The mission's top objective is to find Aten-class asteroids, objects which orbit 
the sun mostly within Earth's orbit. Another focus of NEOSSat's mission is 
asteroids which spend all of their time inside of Earth's orbit.

Such asteroids have mostly eluded ground-based telescopes and other space 
observatories.

Engineers installed a baffle in NEOSSat's telescope to shield the instrument's 
detectors from intense sunlight.

Most telescopes avoid pointing near the sun, which can damage sensitive telescope 
components. The WISE mission, for example, never pointed within 90 degrees of the 
sun as it orbited Earth.

NEOSSat's objectives require it to regularly point within 45 degrees of the sun, 
and sometimes as close as 20 degrees.

"Our search strategy is optimized to find those guys," Hildebrand said in an 
interview with Spaceflight Now. "It means we're looking forward and behind the Earth 
as close to the sun as we can, along the ecliptic plane. We cover a relatively small 
chunk of sky as faint as we can to discover those asteroids."

Kroupnik said NEOSSat could discover between four and 12 asteroids per month larger 
than 500 meters, or 1,640 feet, in diameter, depending on their albedo, 
or reflectivity. Scores of smaller asteroids could be found by NEOSSat, 
which is due to operate at least one year.

"It all depends how close an asteroid is to the Earth when it passes through the 
NEOSSat field of view," said Paul Chodas, a researcher in the near-Earth object 
program office at NASA's Jet Propulsion Laboratory and a member of the NEOSSat 
science team.

Some of NEOSSat's discoveries could be ideal targets for future robotic or human 
exploration, Hildebrand said. Asteroids in orbits closely matching Earth's are 
easiest to reach with space missions.

NEOSSat will also conduct follow-up observations of known asteroids.

"[NEOSSat] doesn't cover very much sky per day, so it isn't very useful for 
detecting small asteroids on a collision [course] with Earth," Hildebrand said. 
"I think that the most useful thing that we might do there is to provide 
astrometry on an incoming object - if it were in a difficult part of the 
sky for ground-based telescopes - to establish its impact location on 
the Earth."
 
Canadian scientists first proposed building a microsatellite 
to hunt for asteroids in 2000, but the project did not become a reality 
until 2005.

"At the time, Canada was building another microsatellite 
with a small space telescope," Hildebrand said. "The question was asked, 
what could we do with this technology? So we explored what could be done 
in terms of asteroid searching, and we identified the highest value was 
being able to look near the sun."

In order to keep costs down, officials reused a proven instrument and spacecraft 
design from Canada's MOST space telescope, and NEOSSat's detectors were spares left 
over from the MOST mission.

NEOSSat's total cost, including development and operations, is estimated to be 
about $24 million, according to Kroupnik. Its prime contractor is Microsat 
Systems Canada Inc.

The cost was evenly split between the Canadian Space Agency and Defence Research 
and Development Canada, which will use the spacecraft to test space surveillance 
technologies.

"The unique aspect of NEOSSat is not that we will be conducting space surveillance 
from space, but rather that we will be conducting it from a microsatellite 
platform," said Brad Wallace, principal investigator for NEOSSat's military 
mission. "Thus, as part of our research and development goals, we will 
be using NEOSSat to test and demonstrate the ability of this small, inexpensive 
platform to support a range of space surveillance applications."