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Satellites

Celebrating the 40th anniversary of Alouette II

On November 29, 1965, CBC television news reported: "The second satellite in the Alouette series was sent into orbit today, confirming the success and ingenuity of Canada's top scientists." The highly sophisticated satellite Alouette II would study the ionosphere "to improve the quality of communication transmissions in the Canadian North."

November 2005 marks the 40th anniversary of the launch of Alouette II, an important event in Canadian space history.

After the launch of Alouette I in September 1962, which had ushered Canada into the space age, Canada and United States collaborated to launch similar satellites under a program called the International Satellites for Ionospheric Studies (ISIS) program. Like Alouette I, the ISIS satellites would study the ionosphere, an electrically charged layer of the upper atmosphere, and the aurora borealis.

Why study the ionosphere?

Before communications satellites, radio signals were transmitted over long distances by bouncing them off the ionosphere. Canadian scientists had studied this part of the atmosphere for years from the ground. But they realized that they needed to probe the ionosphere from above as well as below because the aurora borealis often disrupted radio transmissions. The satellite instruments would measure temperature, density, and activity in the magnetic field.

The Alouette/ISIS program produced data that supported the publication of over 1,200 papers and scientific reports. Both Alouette satellites were used for 10 years; the ISIS satellites were used until March 13, 1984, when the program ended and Canada transferred the authority to operate them to the government of Japan.

The Alouette II design team

Originally built as a back-up model for its predecessor, Alouette II was designed and refurbished by a team of scientists at Canada's Defence and Research Telecommunications Establishment (DRTE), under the leadership of physicist Dr. John Chapman, who first elaborated the Canadian Space Program.

Its 10-year mission placed it in an orbit with an apogee, that is, where it's farthest from the Earth, of 2,982 kilometres, almost three times the peak height of Alouette I. Alouette II was the first of three satellites to launch under the Canada-U.S. agreement. ISIS I followed in 1969 and ISIS II in 1970.

A strong base for Canada's space program

The Alouette and ISIS satellites performed extremely well. Canada had become the third nation in space and had earned an international reputation for excellence in satellite design and engineering. Today, its position as a leader in satellite communications, Earth observation, and space science rests on the solid foundation laid by the Alouette satellites.