This week Canadian satellite “RADARSAT-2″ will launch on a Soyuz vehicle from Russia’s Baikonur Cosmodrome in Kazakhstan. RADARSAT-2 is Canada’s next-generation commercial SAR (Synthetic Aperture Radar) satellite, which follows RADARSAT-1, launched in 1995. SAR satellite imagery can be acquired at any time of the day or night and during adverse weather conditions.
The RADARSAT-2 Bus, complete with thermal hardware,
at the David Florida Laboratory (DFL) in Ottawa.
See the following story that ran in yesterday’s Globe and Mail:
A hawkeyed addition to Canada’s Arctic arsenal
Nothing larger than a car will escape the gaze of Radarsat-2, set to monitor climate change and traffic in the North
Paul TaylorFrom Monday’s Globe and Mail
December 10, 2007
A Canadian satellite is to blast into orbit this week with the explicit goal of monitoring the country’s environment and natural resources from space.
But in the age of global warming, the high tech eye-in-sky, called Radarsat-2, could soon be playing a pivotal role in defending Canada’s territorial claims in the high Arctic.
“The ice in the north will continue to melt and that means … international ships will be going through the Northwest Passage,” said Luc Brulé, who is project manager for Radarsat-2 at the Canadian Space Agency. “So we need ways and means to control that passage because these are Canadian waters … and Radarsat will help us better monitor what’s happening up north.”
From an altitude of 800 kilometres, the Canadian satellite will be able to pinpoint any foreign vessels – and neither the darkness of night nor stormy weather can obstruct its view.
The satellite will use cloud-penetrating radar, rather than a conventional optical camera, to capture images of what’s happening on the ground. Nothing bigger than a family car can hide from its gaze.
Right now, the satellite is tucked into the nose cone of a Russian-built Soyuz rocket at the Baikonur Cosmodrome launch complex in remote Kazakhstan. If everything goes according to plan, the rocket will lift off on Friday morning and put Radarsat-2 in an orbit that will take it over the north and south polar regions once every 100 minutes.
Canada’s new piece of space hardware is actually a juiced-up version of earlier satellite called Radarsat-1 that was launched in 1995. It was supposed to last just five years, but is still going strong today. It helped establish Canada as a key player in polar research using satellite imagery. It provided the first detailed maps of Antarctica and charted the flow of glaciers in Greenland. Climatologists will be able to use this data as a baseline for assessing the effects of global warming on the melting of polar ice.
Radarsat-2 has the potential to do more than its predecessor because it’s packed with more powerful and versatile equipment. It will have a resolution of three metres, instead of the current 10.
“With Radarsat-1 we can pretty much see objects the size of a house, but with Radarsat- 2 we should be able to sees cars on the images,” Mr. Brulé said.
The satellite works by beaming radar waves down to the Earth and then catching the signals that bounce back. The resulting image is essentially a mixture of light and dark areas, representing the strength of the returning signals. False colour can be added to highlight details.
Although it may seem like a simple process, a lot of sophisticated data can be gleaned from the signals. When analyzed by computer programs, the radar images can be use to check the health of agricultural crops, pinpoint oil spills on the open ocean and calculate the thickness of sea ice.
Various Canadian government departments already rely heavily on Radarsat-1. “A lot of imagery is taken over the Gulf of St. Lawrence because of the ice cover in winter,” Mr. Brulé said. “You can see where the ice is thick or thin and provide maps to ships.”
Furthermore, Radasar-1 has turned into a money-making venture. Foreign governments and corporations routinely buy its data. Australia, for instance, is using Radarsat-1 images to catch alien fishing ships poaching in its coastal waters.
One of the main reasons for launching the new and improved Radarsat-2 is to expand these commercial operations. When Radarsat-2 was still on the drawing board, the Canadian Space Agency struck a deal with Vancouver-based MacDonald, Dettwiler and Associates Ltd. to act as the primary contractor.
The Canadian government is contributing $430-million to the building and launch costs, while MDA (best known as the company behind the Space Shuttle’s Canadarm) is chipping in $92-million. Once in orbit, MDA will own the satellite and cover the operating costs expected to be $15-million a year. Canadian government departments will have free access to all the Radarsat-2 imagery they want. Commercial sales will then be up to MDA.
“There is a business risk,” said John Hornsby, general manager of MDA’s Radarsat division, Geospatial Services. He noted that Radarsat-2 will face growing competition from radar-based satellites of other countries, including Germany’s recently launched TerraSAR-X.
Still, MDA won’t be able to peddle the images to whoever might want them. Certain information, if it falls into the wrong hands, could pose a security risk. The company will be operating under a special federal licence, “which specifies what we can and cannot do,” Mr. Hornsby said.
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How old is that ice?
How can you determine the thickness of sea ice from 800 kilometres up in space?
Canada’s new Radarsat-2 satellite should be able to achieve this task merely by bouncing radar waves off the ice and interpreting the returning signals.
Newly formed ice is usually smooth. With very few surface details, the radar waves bounce away form the orbiting spacecraft, producing a very weak returning signal. On the other hand, older ice tends to be well-packed and rugged. Its uneven surface provides lots of edges that can catch the radar waves, resulting in a powerful signal being transmitted back to Radarsat-2′s receivers.
By analyzing the varying strengths of the signals, the age of the ice can be estimated, said Luc Brule of the Canada Space Agency, because new ice tends to be a lot thinner than well-packed older ice.
