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August 25, 2017 - Landsat 7 Reaches Peak Outer Boundary

Landsat 7 recently reached its peak outermost boundary of 10:14:58 Mean Local Time (MLT) on August 11, 2017, since the final Delta-Inclination (Delta-I) maneuver took place on February 7, 2017.

The satellite will now begin drifting in its inclination and will continue to do so until the end of its science mission in early July 2021, or by the launch of Landsat 9 (planned for December 2020).

The Delta-I maneuver was done to ensure that the satellite always crosses the equator at 10 a.m. plus-or-minus 15 minutes local time. Scientists want the sun’s angle on the landscape they’re studying to be the same image to image, month to month, year to year, so it is important that Landsat 7 crosses locations on the globe at roughly the same time every time.

The February Delta-I maneuver exhausted the satellite’s fuel for any further inclination burns with the exception of the final burns to deorbit the satellite. Assuming continued nominal spacecraft and instrument performance, the satellite may continue its science mission until it reaches a threshold boundary of 9:15 MLT.