A few hours ago the Aeolus satellite was launched on a Vega rocket from the Kourou base in French Guiana. After almost 55 minutes it successfully separated from the rocket’s last stage and entered its Sun-synchronous orbit at an altitude of 320 kilometers (about 200 miles), from where it will study winds globally.
Aeolus – full name Atmospheric Dynamics Mission Aeolus, ADM-Aeolus – is a relatively small satellite with its mass at the launch of 1,366 kg which represents the final product of a project that started almost twenty years ago. Due to the long development time caused by problems in putting together the various parts of a very sophisticated instrument, the project included a compatibility with various rockets. The development of the Vega rocket in recent years led to its choice for this mission.
The orbit of the Aeolus satellite is Sun-synchronous and this means that it passes over a certain area of the Earth always at the same local solar time. From that orbit it will detect a series of information on winds to make up for a knowledge that’s still too limited. Currently, direct detections are generally carried out with probes that are launched daily, especially in the northern hemisphere. Other detections are carried out from the ground, from boats and airplanes. The result is far from complete.
Part of the ESA’s Living Planet Program and in collaboration with the Global Observing System (GOS), which aims to coordinate and improve meteorological and environmental surveys, the Aeolus mission should finally provide global wind surveys. This will bring a lot of new information to improve weather forecasts and climate models.
To accomplish its mission, the Aeolus satellite is equipped with an instrument called Atmospheric LAser Doppler INstrument (ALADIN). This instrument consists of three main parts: an ultraviolet Lidar, a receiver for the Mie and Rayleigh scattering and a 1.5 meter Cassegrain telescope.
During the operations, the Lidar generates ultraviolet light sent to the Earth. That light bounces off air molecules and particles such as dust, ice and water droplets in the atmosphere. The fraction of light bounced back to the Aeolus satellite is detected by the telescope and measured.
The goal is to measure 100 wind profiles per hour, down to the ground if the sky is clear or not very cloudy or down to the top of clouds if they are thick. The data will be sent to weather centers with a very short delay so that they can be processed as soon as possible to get the best weather forecasts.
Now the Aeolus satellite’s test will start and go on for several weeks to verify that everything works fine. If all goes well, at the end of the tests it will begin its primary mission, which has a duration of 3 years.