Canadian Space Agency (CSA) flight controllers in St Hubert continue to try to regain communication with Radarsat-1 after an anomaly forced it into a safe mode March 29th. Flight controllers were working through a recovery procedure when contact with the spacecraft was lost.
The anomaly took place at 7:33 on March 29th when Radarsat-1 was in its 90,820th orbit. During one of the scheduled communication passes over the CSA Headquarters in St Hubert Quebec, there was a negative telemetry lock – they could not communicate with the spacecraft.
During a later pass it was determined that Radarsat-1 was in a “Safe Hold” mode – an automatic mode it places itself in when something goes wrong. It puts itself in a safe position where it can wait for help from flight controllers on the ground.
Michel Doyon is the Manager of Satellite Flight Operations at St Hubert. He explained what happened next. “We initiated recovery procedures but as the day continued, it was not working as expected. We have a team of experts analyzing the situation, looking at the root cause. We suspect the problem is in the power distribution system.”
The Flight operations have been monitoring Radarsat-1 continually since its launch in 1995. During these 17-plus years, only a few systems on the spacecraft have failed.
The spacecraft was outfitted with many backup systems, but until now, few have been needed. In 2003, a pitch wheel failed. Pitch wheels are spinning weighted metal wheels inside the spacecraft which help to control its attitude or position in space. A workaround was found and it has been working fine since. Last year, one of the communication systems failed. They have been using the backup since then without problem.
Despite its age, there has not been any talk about shutting Radarsat-1 down. It continues to provide valuable data and the required funding has been found to run the program.
Michel Doyon says that they are not going to give up. “It is a serious anomaly. It’s premature now to say which way it is going to go. We are putting all of our efforts to recover from this. We’re still working hard trying to figure things out and hopefully we can resolve it.”
What are the chances that Radarsat-1 will be recovered? Not very good.
During recovery operations, all communications with Radarsat-1 were lost. The flight controllers are trying to send commands to the spacecraft to re-initiate the recovery process, but by now the spacecraft may be tumbling and pointing its solar arrays away from the sun. The batteries are discharging and once fully discharged, Radarsat-1 will not hear any commands and will not be recoverable.