NASA’s Scientific Visualization Studio illustrates how the Terra Orbit Drift will impact Terra ASTER and Terra MODIS land data products as the satellite moves closer to Earth.
Terra has orbited Earth for over twenty years collecting data important to Earth’s systems research and applications. Crossing the equator at 10:30 am mean local time allowed Terra’s ASTER and MODIS instruments to collect a consistent historical record that has provided the science community with a valuable archive of land data products.
In February 2020, Terra used some of its limited fuel supply to complete an inclination maneuver to maintain the 10:30 am crossing time. Terra continues to drift to an earlier equatorial crossing time and will be lowered to a new orbit corresponding to an Earth Sciences Constellation exit in October 2022.
The Scientific Visualization Studio graphic linked above depicts the small changes in data and imagery that are expected following Terra’s drift in orbit over the next few years. Evidence in the earlier crossing time will be visible as longer shadows, especially in mountain landscapes. In addition, the sensor views will become narrower leading to slightly smaller swath widths. The effect will be most noticeable in ASTER imagery but will also affect MODIS data. The impact on science quality is expected to be minimal as Terra continues to acquire data through end of mission.
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