Tim Furniss Martin Hindley/LONDON

CANADA HAS launched the world's first operational radar satellite, which it will use to monitor the Earth's surface, particularly ice movements in the North- west Passage and Beaufort Sea, both strategic shipping routes.

The Radarsat I, a synthetic-aperture radar (SAR) satellite, was launched on 4 November from the modified Space Launch Complex (SLC) 2 at Vandenburg AFB, California, aboard a McDonnell Douglas Delta 2 rocket, into a 792km (428nm)-circular polar orbit. It marks Canada's entry into the remote-sensing-satellite market as the third-largest participant.

Designed and built by Mississauga, Ontario-based Spar Aerospace, the C$620 million ($453 million) Radarsat will also provide commercial customers with images of a resolution down to 8m, through the Radarsat International (RSI) consortium. In return for providing the launch, the USA will have 15% access to the satellite's data, with RSI member Lockheed Martin holding the US distribution rights.

The satellite is designed to orbit the Earth in around 100min, collecting up to 400min of data a day. The first data are expected in February 1996 and will be used by Canadian engineers to calibrate the satellite's instrumentation as part of a three-month commissioning programme.

Norway's Tronso and the UKs Defence Research Agency will be among the first to download data from the satellite when it enters full commercial service in the middle of 1996. The SAR technique is an extension of conventional satellite imaging, but uses radio-frequency signals (C-Band microwaves), instead of light, to pick out surface features. The satellite's motion is used to create a "virtual" 4km-long antenna, which produces a footprint measuring about 2,800km across.

Also launched with the Radarsat was NASA's Surfsat mini-satellite, a test vehicle, which will be used to support training for tracking-station personnel at the agency's Deep Space Network.

Source: Flight International