News
Update on the Jason-1 orbit change
Last maneuvers have put Jason-1 higher than planned. The drift phase should thus last longer. The altimeter could be switch on on February 10, during the drift phase.
Due to two consecutive slight over burns in the thrusters of the satellite, the recent maneuver conducted on February 6 has put Jason-1 only 469 m below the nominal operational orbit, instead of the desired 1,000 m below. Because of this higher-than-expected intermediary orbit, the fifth and final maneuver to accurately place Jason-1 back into the nominal operational orbit must be delayed and will not take place until February 14, 2009, at the earliest. (A higher than expected intermediary altitude means that it will take Jason-1 longer to drift to the rendezvous point for the final maneuver). Further orbit analysis and characterization will be performed in the coming days to confirm these preliminary results and plan the final maneuver sequence.
It should now be safe to turn on the altimeter at the present altitude while Jason-1 finishes the drift phase. Planning is to turn on the altimeter on February 10. This should give about 4-5 days’ worth of altimeter data in drifting orbit. This early turn-on of altimeter should also minimize disruption to the AMR operating temperature for better calibration after returning to science data collection in the new nominal orbit.
Image of the month 
