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NEOSSat

NEOSSat: Canada's sentinel in the skies

Canada is currently building NEOSSat (the Near-Earth Object Surveillance Satellite), the world's first space telescope dedicated to detecting and tracking asteroids and satellites. Slated for launch in 2011, NEOSSat will circle the globe every 100 minutes, scanning space near the Sun to pinpoint asteroids that may someday pass near our planet. It will also act like a celestial traffic reporter for satellites and space debris orbiting high above the Earth, searching for hazards to spacecraft that play an integral part of our daily lives.

Asteroid Alert!

It's the stuff of video games and Hollywood blockbusters: a giant asteroid on a collision course with Earth. Our planet has, in fact, been hit by many meteorites, leaving behind impact craters like the one on Devon Island in Canada's north (used by researchers to simulate missions to Mars), and the Manicouagan crater in Quebec. Sometimes meteorites land in uninhabited areas or simply splash into the oceans, and are never found. But occasionally the consequences have been catastrophic. Scientists have found evidence that a very large meteor struck the Yucatan peninsula in Mexico about 65 million years ago, and may have created a sudden and massive climate change that wiped out the dinosaurs. Our planetary neighbours have not escaped these cosmic crashes either: the Moon, Mars, Mercury, Jupiter and two of Jupiter's moons (Calisto and Ganymede) all bear the circular scars of these violent encounters.

Recent impact on Jupiter
Credit: NASA, ESA, and H. Hammel (Space Science Institute, Boulder, Colorado)
and the Jupiter Impact Team.

The dark patch in this image of Jupiter, taken by the Hubble Space Telescope on July 23, 2009, was caused by the impact of a comet or an asteroid, creating an expanding spot that is twice the length of the Canada in size. First discovered by Australian amateur astronomer Anthony Wesley, the feature is the impact site and "backsplash" of material from a small object that plunged into Jupiter's atmosphere and disintegrated. The only other time in history such a feature has been seen on Jupiter was in 1994 during the collision of fragments from comet Shoemaker-Levy 9. The actual object that hit the planet is estimated to be the width of several football fields. The force of the explosion on Jupiter was thousands of times more powerful than the suspected comet or asteroid that exploded in June 1908 over the Tunguska River Valley in Siberia.

There are at least 5000 known asteroids and comets in the Earth's backyard. More problematic, there are many more that have not been discovered that could pose a threat to Earth. Several international organizations keep a close watch on known asteroids using ground-based observatories. But, as amateur astronomers know all too well, it's tough to scan the skies from the ground. It is especially difficult to spot relatively small objects that appear near the Sun and its blinding light. This is where Canadian scientists saw a niche they could fill.

Although NEOSSat's 15-centimetre telescope is smaller than the instruments used by many amateur astronomers, its location—circling approximately 700 kilometres above the Earth—will give it a huge advantage as it searches space near the Sun for faint signs of moving asteroids.

"NEOSSat will give us terrific skies for observing 24-hours a day, guaranteed," says Dr. Alan Hildebrand of the University of Calgary, who leads NEOSSat's NESS (Near Earth Space Surveillance) asteroid search program. "NEOSSat will discover many asteroids much faster than can be done from the ground alone."

Aside from the potential hazard they pose to Earth, asteroids and comets are objects of considerable interest to scientists. These primitive bodies formed early in the evolution of the Universe and may hold important clues to the formation and origin of the Solar System. Some are also tantalizingly within our reach. " NEOSSat's most exciting result...will probably be discovering new targets for exploration by both manned and unmanned space missions," Hildebrand observes. "By looking along Earth's orbit, NEOSSat will find 'low and slow' asteroids before they pass by our planet...missions could be launched to explore them when they are in the vicinity of the Earth," Hildebrand adds.

Doing Double Duty

In February of 2009, two spacecraft (one that had ceased operations, the other still operating), collided at speeds of more than 40 000 km/h. This collision created hundreds of pieces of debris that continue to circle the Earth every hundred minutes, each playing a potentially catastrophic game of dodgeball with every spacecraft in their path. NEOSSat's second objective-helping keep track of spacecraft—will to try to make sure that such collisions do not happen again.

In addition to searching for asteroids, NEOSSat will also update the positions of satellites and space debris orbiting high above the Earth as part of a project by the Defence Research and Development Canada (DRDC) known as HEOSS (High Earth Orbit Surveillance System). While this has been done from space before, it has never been done using such small spacecraft (technically referred to as a "microsatellite").

"NEOSSat is a technological pathfinder for us to demonstrate the potential of microsatellite technologies to satisfy operational requirements of the Canadian Forces," explains Major Tony Morris of the Department of National Defence. "NEOSSat will demonstrate the ability of a microsatellite to enhance the Canadian Force's contribution to the NORAD mission—providing accurate knowledge of the traffic orbiting our planet. This would contribute to the safety of critical Canadian assets, military and civilian, in an increasingly congested space environment."

HEOSS will demonstrate how a microsatellite could contribute to the Space Surveillance Network, a network of ground-based telescopes and radars located around the world. Data from HEOSS will enhance Canada's contribution and will offer significant advantages to the network. NEOSSat will be able to continuously track satellites and space junk in a wide variety of locations and not be limited by geographic location and the day-night cycle as ground-based telescopes are.

The Little Telescope that Could

NEOSSat is the technological successor to Canada's highly successful MOST space telescope, building upon its predecessor's technology to help reduce design and building costs. Like MOST, NEOSSat is a featherweight as far as satellites go: the size of a large suitcase, it tips the scales at a mere 75-kilograms, and operates with only 50 watts of solar power. In the space industry, where lighter means cheaper, NEOSSat's price tag of approximately $15 million is a bargain for such a high-performance satellite.

In order to meet the demanding scientific requirements for the MOST mission, Canada's space industry has carved out a unique niche in developing technology that allows MOST's telescope to zero-in on a particular star for weeks at a time. NEOSSat will push the technological envelope even further. "NEOSSat requires remarkable agility and pointing stability that has never before been achieved by a microsatellite," says David Cooper, Chief Executive Officer of Mississauga-based Microsat Systems Canada Inc., the manufacturer of NEOSSat (under sub-contract from Dynacon) and operator of MOST. "It must rapidly spin to point at new locations hundreds of times per day, each time screeching to a halt to hold rock steady on a distant target, or precisely track a satellite along its orbit, and 'image-on-the-run'. Microsat Systems Canada Inc is the world leader in this microsatellite attitude-control-system technology."

Building on MOST's technological heritage will be critical to NEOSSat's goals. "We have already done satellite tracking tests using the MOST spacecraft, so we know that a microsatellite can track satellites," says Dr. Brad Wallace, who leads the science team at Defence Research Development Canada for HEOSS. "The challenge now is to demonstrate that it can be done efficiently, reliably, and to the standards required to maximize the safety of the spacecraft that everyone uses daily, like weather and communication satellites."

Partners

NEOSSat is jointly funded by the Canadian Space Agency (CSA) and Defence Research and Development Canada (DRDC). The satellite is built by Microsat Systems Canada Inc., with support from Spectral Applied Research and Routes AstroEngineering. The two Principle Investigators are Dr. Brad Wallace from DRDC and Dr. Alan Hildebrand from the University of Calgary. Dr. Hildebrand leads the Near Earth Space Surveillance project with scientific collaborators from the University of British Columbia, the Planetary Science Institute, the University of Arizona, the University of Western Ontario, the University of Hawaii, NASA, and SAIC. Brad Wallace leads the High Earth Orbit Space Surveillance project and the science team whose mission is to track satellites and debris in High Earth Orbit.

Send your name to space aboard NEOSSat!

Celebrate the International Year of Astronomy 2009 by sending your name to space aboard NEOSSat. Sign up now! All names will be uploaded to the satellite's computers in 2011.

Links

NEOSSat team website: www.neossat.ca

Defence Research and Development Canada: www.drdc-rddc.gc.ca/

Microsat Systems Canada Inc.: www.mscinc.ca/