ESA’s fifth Earth Explorer - Aeolus - is due to retire soon, but will provide fully nominal data up to the end of operations on 30 April.

Launched in 2018, over its nearly five years lifetime, orbiting Earth 16 times a day and covering the entire globe once a week, its instrument has beamed down over seven billion laser pulses.

Aeolus carries a Doppler wind lidar known as ALADIN. A laser shoots pulses of ultraviolet light towards Earth’s atmosphere, and a receiver detects the light that is scattered back from air molecules, water molecules and aerosols, such as dust.

Supported by the ground segment team, well over 99.5% of the data collected reach users such as weather forecasters within three hours.

Researchers recently concluded that Aeolus data could also improve forecasting of hurricanes in regions of the planet where reconnaissance flights are sparse, particularly over the tropics.

Over forty experts of the Aeolus DISC (Data, Innovation and Science Cluster), collaborated for years in calibration and validation activities, including tens of thousands of kilometres flown in field campaigns from Greenland to Cape Verde, sharpening and improving the instrument and quality of its data.

So, why is it retiring?

The satellite has reached its designed life time and will be prepared to re-enter from space after having completed a number of important scientific and technological experiments.

Legacy of Aeolus

The success of Aeolus resulted in the decision to create a follow-on mission, called Aeolus-2, which will provide data continuity. Aeolus-2 will be launched within a decade.

Though no new NRT data for operational use will be acquired by Aeolus after 30 April, the almost five years dataset acquired by the satellite will continue to provide value in long-term studies of changes to Earth’s atmosphere.