Landsat 9 Underfly, November 2021

The newly launched Landsat 9 experienced a once-in-a-mission lifetime event where its orbit was directly below Landsat 8 for an “underfly.” For several days in the middle of November, the pair of Earth-observing satellites flew together, collecting data at the same time for the same sites and requiring simultaneous downlinking to global ground station antennas.

Read more about this event.

Animation: the Earth revolves as two satellites, Landsat 8 and Landsat 9, orbit. Their paths are indicated with blue and green.

A bar indicates a progression through a 7 day span, starting on November 11th.

Throughout the animation, the descending paths of Landsat 8 and Landsat 9 over the United States overlap in varying degrees, starting with a November 12th 10% overlap on the west portion of Landsat 8's swath, then a 100% overlap on November 14th, then 10% again on the eastern side, November 16th.

Field teams are indicated by yellow dots across the U.S., Canada, Australia, India and Indonesia.