Mission background

The European Space Agency (ESA) wind mission, Aeolus, hosts the first space based Doppler wind lidar world-wide. The primary mission objective is to demonstrate the Doppler wind lidar technique for measuring wind profiles from space, intended for assimilation in Numerical Weather Prediction (NWP) models in Near-Real-Time (within three hours of sensing). The wind observations will also be used to advance atmospheric dynamics research and for evaluation of climate models. Mission spin-off products are profiles of cloud and aerosol optical properties.

Aeolus was the fifth Earth Explorer mission to be launched. The Earth Explorers are specialised missions dedicated to observing different aspects of the planet and our environment. A secondary aim of the programme is to understand how these aspects interact with one another.

The Aeolus mission selection was motivated by the need for more abundant direct wind profile measurements in the World Meteorological Organization (WMO) Global Observing System (GOS), which is used by weather forecast models world-wide. Currently, the global distribution of conventional wind profile measurements is not homogenous and mainly located over land in the Northern Hemisphere. Winds are also inferred from temperature soundings for the large-scale wind fields in the extra-tropics. Scatterometers provide surface winds over the oceans (single level), and Atmospheric Motion Vector (AMV) winds deduced from cloud, aerosol, humidity or ozone tracking are limited in vertical coverage and have less accurate height assignments. The lack of homogenous wind field sampling, in particular in the tropics, over the oceans and in polar areas, hence leads to difficulties in constraining atmospheric models and limits the studying of key processes in coupled climate systems. Aeolus winds contribute to mitigate the current wind observation deficit. Significant weather forecast improvements has been demonstrated by a number of weather centres across the world using Aeolus observations, including the European Centre for Medium-Range Weather Forecasts (ECMWF).

Satellite design

The Aeolus satellite platform structure consists of honeycomb elements, using a conventional cubical spacecraft design, derived form the ESA mission MarsExpress. The platform is 4.6 m x 1.9 m x 2.0 m, with a total mass of 1360 kg (including 266 kg fuel).

The platform hosts two solar arrays, mounted on each side of the satellite platform. Each array is 13 m long, and contain three panels. The platform power comes from the 2.4 kW deployable solar arrays (2 x 3 panels) with GaAs cells, and the 84 Ah Li-ion battery.

The Aeolus instrument payload, ALADIN, has a cylindrical structure including a 1.5 m diameter telescope surrounded by a baffle, and is mounted on top of the satellite platform.

Aeolus platform
Aeolus platform - Copyright: ESA/ATG medialab

Mission Operations

Aeolus orbit
Aeolus orbit

Aeolus flies in a Sun-synchronous orbit at a mean altitude of 320 km. Approximately 16 orbits are achieved per day and the satellite has a seven day repeat cycle with an orbital period of 90 minutes.

For real-time housekeeping telemetry downlink and telecommanding, the Aeolus mission is using ESA's ESTRACK ground station in Kiruna. Scientific payload data acquisition is guaranteed with the combined usage of Svalbard and Troll X-band receiving stations.

Flight operations are conducted at the European Space Operations Centre (ESOC) and maintenance is performed from the European Space Research and Technology Centre (ESTEC). The Payload Data Ground Segment (PDGS) provides core operational functions including science data acquisition, systematic generation of Aeolus data products in Near Real time (NRT), reprocessing, data preservation, data access and user services. X-band data acquisition and systematic data generation activities (up to L2A product level) in NRT are delivered as part of the COSA Service (Core Operational Services for Aeolus) by KSAT/Norway.

ECMWF, the European Centre for Medium-Range Weather Forecasts, produces systematically L2B and L2C Aeolus Wind products as part of the DAMI Service (Dedicated Data Processing and Data Delivery Services for Aeolus Mission).

Track the Aeolus mission in orbit in real time using the ESTRACKnow tool.

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