Radarsat-1 Orbit Adjustment Notification

Note: The following notice was received from the CSA and forwarded to ASF data users May 7, 2004.

On Sunday April 25th, a routine manoeuvre to adjust the orbit of RADARSAT-1 resulted in a slight modification of the nominal orbit of a 24-day repeat cycle. Since that event, the Canadian Space Agency, in consultation with its program partners, has been looking at several scenarios to correct the situation.

In the end, in the interest of the program, it has been decided that an orbit manoeuvre will be implemented shortly to get back to the nominal orbit. To proceed with this manoeuvre, a 48-hour long total payload outage will be required beginning at 17-MAY-04 at 19:00 UTC. With this manoeuvre the nominal orbit and ground track would be restored by the end of the month. In the mean time, users may be seeing a difference in the location of the actual acquired data compared with that ordered, especially in the cross-track direction.

This situation should be corrected shortly for the interim period by the release to the order desks of a new version of the Swath Planning Application (SPA) tool that will include a proper correction. The Canadian Space Agency and its program partners are keeping their clients informed and working together to ensure that the impact on clients is minimized during the interim period.

Maneuvers were performed by CSA in mid and late May to readjust the satellite’s orbit. Radarsat-1 was reported back to nominal status by June 1. All data acquired between April 25 and June 1 will not be appropriate for interferometry.

However, the data can still be processed successfully for applications requiring backscatter images. There was some cross-track drift occurring that altered the area covered. Feel free to contact ASF User Services with any concerns or questions you may have (uso@asf.alaska.edu).

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