ESA’s Trailblazing Aeolus Mission Comes to a Historic End

ESA’s Trailblazing Aeolus Mission Comes to a Historic End

Aeolus, ESA’s wind mission reentered Earth’s atmosphere on 28 July at around 21:00 CEST above Antarctica, confirmed by US Space Command. The reentry comes after a series of complex manoeuvres that lowered Aeolus’ orbit from an altitude of 320 km to just 120 km to reenter the atmosphere and burn up.

Crucially, these manoeuvres – the first assisted reentry of its kind – positioned Aeolus so that any pieces that may not have burned up in the atmosphere would fall within the satellite’s planned Atlantic ground tracks.

Today, satellite missions are designed according to regulations that require them to minimise the risk of causing damage on their return to Earth. This would typically be achieved by the majority of a satellite burning up on reentry or through a controlled reentry at the end of its life in orbit.

However, when Aeolus was designed back in the late 1990s no such regulations were in place.

So, after running out of fuel and without intervention, Aeolus would have reentered Earth’s atmosphere naturally within a few weeks from now – but with no control over where this would happen.

Satellites and rocket parts fall back to Earth roughly once a week, and pieces that survive have only very rarely caused any damage, so the risk of Aeolus causing harm was always incredibly small. In fact, the chance of being struck by a piece of debris is three times less than being struck by a meteorite.

Nevertheless, ESA went above and beyond for Aeolus and attempted a new way of assisting its reentry to make it even safer.

Essentially trying to make a satellite do what it was never designed to do involved a huge amount of thinking and a lot of planning.

Then, over the last week, the team of spacecraft engineers, flight dynamics experts and space debris specialists at ESA’s ESOC mission control centre in Germany set to work. They used the satellite’s remaining fuel to carry out a series of burns to lower Aeolus and place it in the best position to reenter.

And they pulled it off – with Aeolus reentering in line with current regulations.

Key stages in Aeolus’ reentry

ESA’s Director of Operations, Rolf Densing, said, “The teams have achieved something remarkable. These manoeuvres were complex, and Aeolus was not designed to perform them, and there was always a possibility that this first attempt at an assisted reentry might not work.

“The Aeolus reentry was always going to be very low risk, but we wanted to push the boundaries and reduce the risk further, demonstrating our commitment to ESA’s Zero Debris approach.

“We have learned a great deal from this success and can potentially apply the same approach for some other satellites at the end of their lives, launched before the current disposal measures were in place.”

This assisted reentry is just one part of ESA’s wider commitment to the long-term safety and sustainability of space activities. By 2030, all ESA missions will be ‘debris neutral’ – thanks to the Zero Debris Charter, the Agency is making sure the technology is ready not just for present-day regulations, but to make possible even more ambitious rules for the future.

From deorbiting kits launched with missions to bring them down safely, to flagship missions like Clearspace-1 that will capture stranded spacecraft in orbit and technologies to limit risks on the ground, ESA is leading the way in sustainable space.

Aeolus: the impossible mission

Aeolus has been a challenging mission – its pioneering laser technology took many years to develop. But after a number of setbacks, Aeolus was finally launched in 2018 to profile Earth’s winds and went on to be one of ESA’s most successful Earth observation research missions.

Aeolus carried an instrument known as Aladin, which is Europe’s most sophisticated Doppler wind lidar flown in space. Its laser fired pulses of ultraviolet light towards Earth’s atmosphere. This light bounced off air molecules and particles such as dust in the atmosphere. The small fraction of light that scattered back towards the satellite was collected by a large telescope.

Through the measurement of the Doppler shifts in the return signals, the horizontal speed of the wind in the lowermost 30 km of the atmosphere was derived, making Aeolus the first satellite mission to deliver profiles of Earth’s wind on a global scale.

The mission, an ESA Earth Explorer research mission, was designed to demonstrate that this technology was feasible – but it did more than that.

ESA’s Director of Earth Observation Programmes, Simonetta Cheli, said, “Aeolus has been truly outstanding. Indeed, the technology was difficult to develop but we have seen huge returns.

“It not only benefited science in terms of contributing to climate research, but its data were used operationally in weather forecasts, which proved essential during the Covid lockdown when aircraft, which carry weather instruments, were grounded.

“A 2022 report by London Economics found that Aeolus also brought real economic benefits – as much as €3.5 billion over the lifetime of the mission.

“We are extremely proud of Aeolus and the many people who made its development, its life in orbit, its data use and its safe end possible.

“And now, with the experience gained from the first Aeolus, our focus turns to its follow-on, Aeolus-2, which is an operational meteorological mission we are developing with Eumetsat, Europe’s Organisation for the Exploitation of Meteorological Satellites.”

Click here to learn more about ESA's Aeolus Mission.

Publisher: SatNow
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GNSS Constellations - A list of all GNSS satellites by constellations


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BeiDou-3 G4Geostationary Orbit (GEO)17 May, 2023
BeiDou-3 G2Geostationary Orbit (GEO)09 Mar, 2020
Compass-IGSO7Inclined Geosynchronous Orbit (IGSO)09 Feb, 2020
BeiDou-3 M19Medium Earth Orbit (MEO)16 Dec, 2019
BeiDou-3 M20Medium Earth Orbit (MEO)16 Dec, 2019
BeiDou-3 M21Medium Earth Orbit (MEO)23 Nov, 2019
BeiDou-3 M22Medium Earth Orbit (MEO)23 Nov, 2019
BeiDou-3 I3Inclined Geosynchronous Orbit (IGSO)04 Nov, 2019
BeiDou-3 M23Medium Earth Orbit (MEO)22 Sep, 2019
BeiDou-3 M24Medium Earth Orbit (MEO)22 Sep, 2019


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GSAT0223MEO - Near-Circular05 Dec, 2021
GSAT0224MEO - Near-Circular05 Dec, 2021
GSAT0219MEO - Near-Circular25 Jul, 2018
GSAT0220MEO - Near-Circular25 Jul, 2018
GSAT0221MEO - Near-Circular25 Jul, 2018
GSAT0222MEO - Near-Circular25 Jul, 2018
GSAT0215MEO - Near-Circular12 Dec, 2017
GSAT0216MEO - Near-Circular12 Dec, 2017
GSAT0217MEO - Near-Circular12 Dec, 2017
GSAT0218MEO - Near-Circular12 Dec, 2017


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Kosmos 2569--07 Aug, 2023
Kosmos 2564--28 Nov, 2022
Kosmos 2559--10 Oct, 2022
Kosmos 2557--07 Jul, 2022
Kosmos 2547--25 Oct, 2020
Kosmos 2545--16 Mar, 2020
Kosmos 2544--11 Dec, 2019
Kosmos 2534--27 May, 2019
Kosmos 2529--03 Nov, 2018
Kosmos 2527--16 Jun, 2018


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Navstar 82Medium Earth Orbit19 Jan, 2023
Navstar 81Medium Earth Orbit17 Jun, 2021
Navstar 78Medium Earth Orbit22 Aug, 2019
Navstar 77Medium Earth Orbit23 Dec, 2018
Navstar 76Medium Earth Orbit05 Feb, 2016
Navstar 75Medium Earth Orbit31 Oct, 2015
Navstar 74Medium Earth Orbit15 Jul, 2015
Navstar 73Medium Earth Orbit25 Mar, 2015
Navstar 72Medium Earth Orbit29 Oct, 2014
Navstar 71Medium Earth Orbit02 Aug, 2014


Satellite NameOrbit Date
NVS-01Geostationary Orbit (GEO)29 May, 2023
IRNSS-1IInclined Geosynchronous Orbit (IGSO)12 Apr, 2018
IRNSS-1HSub Geosynchronous Transfer Orbit (Sub-GTO)31 Aug, 2017
IRNSS-1GGeostationary Orbit (GEO)28 Apr, 2016
IRNSS-1FGeostationary Orbit (GEO)10 Mar, 2016
IRNSS-1EGeosynchronous Orbit (IGSO)20 Jan, 2016
IRNSS-1DInclined Geosynchronous Orbit (IGSO)28 Mar, 2015
IRNSS-1CGeostationary Orbit (GEO)16 Oct, 2014
IRNSS-1BInclined Geosynchronous Orbit (IGSO)04 Apr, 2014
IRNSS-1AInclined Geosynchronous Orbit (IGSO)01 Jul, 2013