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Aeolus, or, in full, Atmospheric Dynamics Mission-Aeolus (ADM-Aeolus), is an Earth observation satellite operated by the European Space Agency (ESA). It was built by Airbus Defence and Space and launched on 22 August 2018.[1] ADM-Aeolus is the first satellite with equipment capable of performing global wind-component-profile observation and will provide much-needed information to improve weather forecasting.[3] Aeolus is 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.

ADM-Aeolus

Artist's view of ADM-Aeolus
Names	Atmospheric Dynamics Mission-Aeolus
Mission type	Weather satellite
Operator	ESA / ESOC
COSPAR ID	2018-066A
SATCAT no.	43600
Mission duration	3 years (planned) 3 years, 8 months and 29 days (in progress)
Spacecraft properties
Manufacturer	Airbus Defence and Space
Launch mass	1,366 kg (3,012 lb)
Dry mass	1,200 kg (2,600 lb)
Dimensions	1.74 × 1.9 × 2 m (5 ft 9 in × 6 ft 3 in × 6 ft 7 in)
Power	2300 watts
Start of mission
Launch date	22 August 2018, 21:20 UTC[1]
Rocket	Vega
Launch site	Centre Spatial Guyanais, ELV
Contractor	Arianespace
Orbital parameters
Reference system	Geocentric orbit
Regime	Sun-synchronous orbit
Altitude	320 km (200 mi)[2]
Inclination	97.0°
Transponders
Band	S-band (TT&C support) X-band (science data acquisition)
Bandwidth	8 kbit/s download (S-band) 10 Mbit/s download (X-band) 2 kbit/s upload (S-band)
Instruments
Atmospheric Laser Doppler Instrument (ALADIN)
Living Planet Programme ← Swarm EarthCARE →

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.[4] For an estimated €481 million (US$568 million) program cost, it should provide 64,000 daily profiles from March or April 2019. Its altitude is a low 320 km (200 mi) for enough backscattered light sensibility,[2] inducing a short 3 years life expectancy.[5]

Mission

Aeolus is the fifth planned satellite in the Living Planet Programme (LPP) of the European Space Agency (ESA). The main goal of this mission is 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 will allow scientists to build complex weather models, which can then be used to help predict how that environment will behave in the future. These predictions will be useful in the short-term, since they can be applied to numerical weather prediction in order to make forecasts more accurate. The mission will thus improve the knowledge of all sorts of weather phenomena, from global warming to the effects of air pollution. Aeolus is seen as a mission that will pave the way for future operational meteorological satellites dedicated to study Earth's wind profiles.

Satellite

The spacecraft was built by Airbus Defence and Space.[6] In 2014, the integration of ALADIN instrument was completed and vacuum along with vibration testing begun.[7]^: 70 On 7 September 2016, ESA and Arianespace signed a contract to secure the launch of the Aeolus satellite.[8]

Scientific payload

The wind-component profiles will be measured by the Atmospheric LAser Doppler INstrument (ALADIN).

ALADIN

The ALADIN instrument (Atmospheric Laser Doppler Instrument) is 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 1.5 m (4 ft 11 in) diameter.[8] The transmitter architecture is based on a 150 mJ pulsed diode-pumped Nd:YAG laser, frequency-tripled to provide 60 millijoules pulses of ultraviolet light at 355 nm.[8] This frequency was chosen because of the increased Rayleigh scattering in the ultraviolet region of the spectrum, and because it is eye-safe at distances greater than several hundred metres.[8][9] The Mie receiver consists 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 is directly linked to the wind velocity; the wind speed is determined by the fringe centroid position to better than a tenth of the resolution (1.8 m/s).[8] The Rayleigh receiver employs a dual-filter Fabry–Pérot interferometer with a 2 GHz resolution and 5 GHz spacing. It analyzes the wings of the Rayleigh spectrum with a CCD; the etalon is split into two zones, which are imaged separately on the detector.[8] The lidar is aimed 35° from nadir and 90° to the satellite track (on the side away from the Sun).[8]

The processing of the backscatter signals will produce line-of-sight wind-component profiles above thick clouds or down to the surface in clear air along the satellite track, every 200 km (120 mi). Wind information in thin cloud or at the tops of thick clouds is also attainable; from the data processing, information on other elements like clouds and aerosols can also be extracted. The data will be disseminated to the main numerical weather prediction centres in near-real time.

Development of the ALADIN instrument has been problematic. The ultraviolet laser was causing damage to the optical surfaces in a vacuum. ESA scientists asked NASA for support; however, NASA has minimal experience with lidar of this design. Technology required for the satellite was pushing the technology envelope; therefore, after problematic development, ESA asked Airbus to perform additional full-model tests in a vacuum before continuing mission development. Overall complications involved in the instrument caused an estimated 50% final cost overrun, so ESA had to come up with additional funding for the project.[10]

Launch

Aeolus was designed to be compatible with many small-capacity launch vehicles such as Vega, Rokot or Dnepr.[11] In November 2013, ESA scheduled the launch on a VEGA in one of the five flights of the VERTA Programme,[6][12] but in 2015 launch was postponed to August 2018 due to problems with their lidar development.[10] A €32.57 million launch contract with Arianespace was signed on 7 September 2016.[13] The launch finally took place on 22 August 2018 on a Vega launch vehicle from French Guiana at 18:20 local time.[14]

Status

The satellite was launched on 22 August 2018. Three months of testing was conducted before including data in weather models.[15] One year of usage has resulted in reduced power from the primary laser. After switching to the second laser, the instrument is meeting mission objectives.[16]

In mid-2019, ESA determined that the UV laser was losing power: it started with pulses of 65 millijoules once it reached orbit, but that energy declined 20 to 30% in the first nine months, and was losing one millijoule per week in May 2019. ESA then decided to switch to a backup laser that had not been used, offering the opportunity to complete the expected 3 year life of the satellite. The report[17] also said that the satellite's orbit at 320 km required re-boosting every week, limiting the satellite's life to the available propellant.

In 2020 it was reported that measurements from Aeolus enabled ECMWF to partly compensate for reduced measurements from commercial aircraft at the start of the COVID-19 outbreak.[18]

In September 2021, since it was launched three years ago, Aeolus has far exceeded expectations and frequently hailed a remarkable success. It was developed as a research mission and to demonstrate how novel laser technology could deliver vertical profiles of Earth's wind. These measurements were much needed, for example by the World Meteorological Organization's Global Observing System, which is a coordinated system of methods and facilities for making meteorological and environmental observations on a global scale.[8]

It is expected to reenter the atmosphere in 2022.

See also

• BIOMASS
• CryoSat and CryoSat-2
• EarthCARE
• FLEX
• Gravity Field and Steady-State Ocean Circulation Explorer (GOCE)
• Soil Moisture and Ocean Salinity (SMOS)
• Swarm

References

External links

Wikimedia Commons has media related to ADM-Aeolus.

• Aeolus page at Airbus Defence and Space
• Aeolus pages at ESA, with latest news
• Aeolus blog by Gilles Labruyère, mechanics engineer in the Aeolus project

На других языках

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[de] ADM-Aeolus

ADM-Aeolus (englisch Atmospheric Dynamics Mission – Aeolus: Griechischer Gott der Winde) ist der Name eines ESA-Satelliten aus der Reihe der Earth Explorer Missions, ein langfristiges Rahmenprogramm der ESA zur Erdbeobachtung. Als erster Satellit überhaupt trägt er als Nutzlast einen Laser und ein Spiegelteleskop, womit nach dem Lidar-Prinzip Luftströmungen großräumig erfasst werden sollen.

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- [en] ADM-Aeolus

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[ru] ADM-Aeolus

ADM-Aeolus (англ. Atmospheric Dynamics Mission Aeolus — миссия [по изучению] динамики атмосферы «Эол») — космический спутник дистанционного зондирования Земли, построенный Airbus Defence and Space[2]. ADM-Aeolus должен стать первым спутником, способным проводить глобальные наблюдения за ветрами от поверхности Земли до 30 км (стратосферы), что позволит получить информацию, важную для предсказания погоды.

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