RADARSAT-1

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Radarsat-1 is Canada's first commercial Earth observation satellite.

Contents

Mission

It was launched at 14h22 UTC on November 4, 1995 from Vandenberg AFB in California, into a sun-synchronous orbit (dawn-dusk) above the Earth with an altitude of 798 kilometers and inclination of 98.6 degrees. Developed under the management of the Canadian Space Agency (CSA) in cooperation with Canadian provincial governments and the private sector, it provides images of the Earth for both scientific and commercial applications. Radarsat-1's images are useful in many fields, including agriculture, cartography, hydrology, forestry, oceanography, geology, ice and ocean monitoring, arctic surveillance, and detecting ocean oil slicks.

History

National Aeronautics and Space Administration (NASA) provided the Delta II rocket to launch Radarsat-1 in exchange for access to its data. Estimates are that the project, excluding launch, cost $620 million (Canadian). The Canadian federal government contributed about $500 million, the four participating provinces (Quebec, Ontario, Saskatchewan and British Columbia) about $57 million, and the private sector about $63 million.

Radarsat International, Inc. (RSI), a Canadian private company, was created in 1989 to process, market and distribute Radarsat-1 data. (Radarsat International, Inc. (RSI) was later acquired by MacDonald Dettwiler and Associates.) In 2006, RSI was rebranded MDA Geospatial Services International or MDA GSI

Payload

Radarsat-1 uses a Synthetic Aperture Radar (SAR) sensor to image the Earth at a single microwave frequency of 5.3 GHz, in the C band (wavelength of 5.6 cm). Unlike optical satellites that sense reflected sunlight, SAR systems transmit microwave energy towards the surface and record the reflections. Thus, Radarsat-1 can image the Earth, day or night, in any atmospheric condition, such as cloud cover, rain, snow, dust or haze.

Each of Radarsat-1's seven beam modes offer a different image resolution. The modes include Fine, which covers an area of 50 km by 50 km (2500 km²) with a resolution of 10 meters; Standard, which covers an area of 100 km by 100 km (10,000 km²) and has a resolution of 30 meters; and ScanSAR wide, which covers a 500 km by 500 km (250,000 km²) area with a resolution of 100 meters. Radarsat-1 also has the unique ability to direct its beam at different angles.

Constellation

With an orbital period of 100.7 minutes, Radarsat-1 circles the Earth 14 times a day. The orbit path repeats every 24 days, this means that the satellite is in exactly the same location and can take the same image (same beam mode and beam position) every 24 days. This is useful for interferometry and detecting changes at that location that took place during the 24 days. Using different beam positions, a location can also be scanned every few days.

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