ADM-Aeolus
Aeolus, or, in full, Atmospheric Dynamics Mission-Aeolus (ADM-Aeolus), was an Earth observation satellite operated by the European Space Agency (ESA). It was built by Airbus Defence and Space, launched on 22 August 2018, and re-entered the atmosphere over Antarctica in a controlled manner and burned up on 28 July 2023. ADM-Aeolus was the first satellite with equipment capable of performing global wind-component-profile observation and provided much-needed information to improve weather forecasting. Aeolus was the first satellite capable of observing what the winds are doing on Earth, from the surface of the planet and into the stratosphere 30 km high. The satellite was named after Aeolus, a god from the Greek mythology, the ruler of the winds. Program The program was initially approved in 1999 for a 2007 launch but technological obstacles caused 11 years of delay, as it was launched on 22 August 2018. For an estimated €481 million (US$568 million) program cost, it was planned to provide 64,000 daily profiles from March or April 2019. Its altitude was a low for enough backscattered light sensibility, inducing a short 3 years life expectancy. Mission Aeolus was the fifth planned satellite in the Living Planet Programme (LPP) of the European Space Agency. The main goal of this mission was to further develop the knowledge of Earth's atmosphere and weather systems. By recording and monitoring the weather in different parts of the world, Aeolus allowed scientists to build complex weather models, which could then be used to help predict how that environment will behave in the future. These predictions were useful in the short-term, since they could be applied to numerical weather prediction in order to make forecasts more accurate. The mission thus improved the knowledge of all sorts of weather phenomena, from global warming to the effects of air pollution. Aeolus was seen as a mission that paved the way for future operational meteorological satellites dedicated to study Earth's wind profiles. Satellite The spacecraft was built by Airbus Defence and Space. In 2014, the integration of ALADIN instrument was completed and vacuum along with vibration testing begun. On 7 September 2016, ESA and Arianespace signed a contract to secure the launch of the Aeolus satellite. Scientific payload The wind-component profiles was measured by the Atmospheric LAser Doppler INstrument (ALADIN). ALADIN The ALADIN instrument (Atmospheric Laser Doppler Instrument) was a direct detection ultraviolet laser lidar consisting of three major elements: a transmitter, a combined Mie and Rayleigh backscattering receiver assembly, and a Cassegrain telescope with a diameter. The transmitter architecture was based on a 150 mJ pulsed diode-pumped Nd:YAG laser, frequency-tripled to provide 60 millijoules pulses of ultraviolet light at 355 nm. This frequency was chosen because of the increased Rayleigh scattering in the ultraviolet region of the spectrum, and because it was eye-safe at distances greater than several hundred metres. The Mie receiver consisted of a Fizeau interferometer with a resolution of 100 MHz (equivalent to 18 m/s). The received backscatter signal produces a linear fringe whose position was directly linked