Canadian scientists unveil plans for asteroid-hunting satellite
Canada's space industry is out to prove again that good science can come in a small package.
On Thursday, the Canadian Space Agency and Defence Research Development Canada announced they are preparing to launch the Near Earth Object Surveillance Satellite, or NEOSSat, a suitcase-sized telescope capable of spotting asteroids and tracking high-altitude satellites and space debris.
NEOSSat follows on the success of the MOST (Microvariability and Oscillations of STars) telescope, the 60 kg star-watching satellite that was launched in 2003 and operates on a shoestring budget.
Like its predecessor, NEOSSat is tiny, with a mass of 65 kilograms and a telescope with a 15-centimetre aperture, smaller than most amateur astronomers' telescopes.
And like MOST, it will be cheap, too, costing $12 million to build, launch and operate.
Scheduled to launch into space in 2010, NEOSSat will have two main science tasks: the NESS (Near Earth Space Surveillance) asteroid search program and the HEOSS (High Earth Orbit Space Surveillance) program, which will track satellites and other objects floating in high orbit around Earth.
First asteroid-tracking space telescope
Asteroid hunting is more than just scientific curiosity, said University of Calgary professor Alan Hildebrand, the chief scientist for the NESS program. Although the orbiting bodies, sometimes called "minor planets," do provide insight into the birth of the solar system, there are many practical reasons to track the paths of asteroids, he says.
Perhaps the chief concern for some is the threat of a collision with Earth. Scientists have found evidence of asteroid collisions with Earth, the most notable being the impact site off the coast of the Yucatan Peninsula in Mexico. The site, buried by ocean sediments today, is thought to be a record of a collision that occurred 65 million years ago. Scientists have theorized that the collision wiped out the dinosaurs by causing an upheaval in the planet's climate.
A more recent collision occurred 100 years ago on June 30, when a small object — thought to be a comet with a diameter of less than 100 metres — impacted near the Tunguska region of Siberia in 1908. The resulting shockwave knocked down trees for hundreds of square kilometres and burned an area about 80 kilometres across.
While NASA's Near-Earth Object (NEO) program office tracks the paths of both near-Earth asteroids and comets from the ground and has discovered over 5,000, NEOSSat will be the first asteroid-tracking telescope to operate from space, a perspective that will allow scientists to track a class of asteroids ground-based observatories normally can't see.
These asteroids, called Aten-class asteroids, are distinctive because the bulk of their orbital path around the sun lies within Earth's orbit. This makes them difficult to spot from ground-based observatories, since the ideal time to spot them from the Earth would be during daytime.
NEOSSat, orbiting 700 kilometres above the Earth's atmosphere, won't be hindered by day-night limitations, said Hildebrand, nor will bad weather affect its view, allowing it to operate 24 hours a day, seven days a week. The satellite, orbiting from pole to pole every 50 minutes, will send dozens of images to the ground each time it passes over Canada.
Because it will be able to take images from either side of the Earth, it will also be able to get a better read on the distances of asteroids by judging their position in relation to the fixed positions of stars, he said.
"We expect that we'll find as many Atens in three years as all the ground-based telescopes have found before," said Hildebrand.
Aten asteroids are important not only because so little is known about them, but also because their orbits make them individually more likely to collide with Earth than other asteroids.
Military eyeing capabilities of micro-satellites
The satellite, funded by the Canadian Space Agency and Defence Research & Development Canada and built by Mississauga-based Dynacon Inc., will also keep an eye on satellites and floating debris orbiting the Earth.
The High Earth Orbit Space Surveillance program will test the satellite's ability to keep an eye on other communications satellites as well as floating debris, such as empty rocket stages from past missions to the moon or expired satellites.
"We'll be able to track the positions and orbits of these objects and forecast where they are going to be," said Laughie Scott, a defence scientist with the HEOSS team. Such knowledge will allow Canada to better keep track of satellites that fail and also allow for safer placement of new satellites.
That information will also enhance Canada's contribution to the North American Aerospace Defence Command (NORAD), said Maj. Donald Bedard, allowing Canada to keep track of its military and civilian space assets.
DRDC is particularly interested in the project as a demonstration mission of the capabilities of a micro-satellite, said Bedard.
"Canadian Forces do not own any satellites and one of the reasons for that is that conventional space satellites are very expensive," he said.
"If you had to put your resources in satellites or other defence capabilities, you'll choose the latter. But if you could build small and less costly satellites, it may open up possibilities," he said.
It's an arena where Canada's space industry has taken a lead, and more companies are showing interest.
Last week, Com Dev International Ltd. announced its intention to build its own micro-satellites and earlier this week signed a contract with the Department of National Defence and the Canadian Space Agency to build the Maritime Monitoring and Messaging Micro-satellite or M3MSat, to keep an eye on Maritime waters.
The smaller projects stand in stark contrast to the Radarsat-2 satellite, the 2,200 kg satellite that the government spent $430 million funding.
Launched last December, Radarsat-2 was hailed by government, space and military officials for its advanced imaging technology and utility as a tool to protect Canada's Arctic sovereignty. It was also at the centre of a political firestorm when the company that owned the satellite — Richmond, B.C.,-based MacDonald, Dettwiler and Associates Ltd. — tried to sell it and other parts of its space business to an American firm. In an unprecedented move, the government blocked that sale.
HEOSS project manager Capt. Tony Morris said micro-satellites are not expected to replace satellites like Radarsat 2. "Radarsat-2 will remain critical for the foreseeable future, but we see micro-satellites as complimentary to those assets."