ESA selects Airbus for exoplanet mission Ariel

The European Space Agency (ESA) has signed a contract with Airbus to build the Atmospheric Remote-sensing Infrared Exoplanet Large-survey (Ariel) mission. Ariel is the fourth medium-class mission in ESA’s Cosmic Vision programme.

Ariel will study the composition of exoplanets, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets in visible and infrared wavelengths. It is the first mission dedicated to measuring precisely the chemical composition and thermal structures of transiting exoplanets. The contract is valued at around € 200 million.

“Airbus has extensive experience of leading ground-breaking science missions, including JUICE, Gaia, Solar Orbiter, LISA Pathfinder and CHEOPS, on which we are building for ESA’s latest science mission, Ariel,” said Jean-Marc Nasr, Head of Space Systems at Airbus.

“In our Toulouse facilities, the largest space site in Europe, we have all the resources, facilities and expertise to design, manufacture and integrate the spacecraft and actively support ESA with payload development. Airbus Stevenage is fully integrated in the prime team for the engineering of the avionics, Radio Frequency communication and electrical design of the platform, as successfully proven for the development of Gaia”.

Airbus will lead the European industrial consortium with more than 60 contractors for building the satellite and provide expertise and support to ESA for the development of the payload module.

“With this milestone for the Ariel mission we celebrate the continuation of the outstanding relationship with our industry partners to keep Europe at the forefront of excellence in the field of exoplanet research well into the next decade and beyond,” said Günther Hasinger, ESA’s Director of Science.

More than 5,000 exoplanets have been identified since the first observation in 1995, but little is known about the chemical composition of their atmospheres. Existing space science missions are delivering results on exoplanets (such as the Airbus-built CHEOPS for ESA), but Ariel will be the first mission dedicated to studying the atmospheres of a large number of exoplanets, including main atmospheric component determination and cloud characterisation. Observations of these worlds will give insights into the early stages of planetary and atmospheric formation, and their subsequent evolution, in turn contributing to the understanding of our own Solar System. They could help us find out whether there is life elsewhere in our universe and if there is another planet like Earth.

The mission will focus on warm and hot planets, ranging from super-Earths to gas giants orbiting close to their parent stars, taking advantage of their well-mixed atmospheres to decipher their bulk composition.

After its launch, in 2029 on an Ariane 6 launcher, Ariel will be injected onto a direct transfer trajectory to the second Lagrangian point (L2). Thanks to its very stable thermal and mechanical design, the spacecraft will be able to carry out long term observations of the same planet/star system for a duration of between 10 hours and up to three days. Its mission will last four years with a possible extension of at least two years.

Airbus was prime contractor for ESA’s mission CHEOPS. Launched in December 2019, its goal is to characterise exoplanets orbiting nearby stars, observing known planets in the size range between Earth and Neptune and precisely measuring their radii to determine density and composition.

Quelle: AIRBUS

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Update: 27.09.2022

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ExoClock counts down Ariel exoplanet targets

Details of the orbits of 450 candidate exoplanet targets of the European Space Agency's Ariel space mission have been presented this week at the Europlanet Science Congress (EPSC) 2022, and submitted for publication in the Astrophysical Journal Supplement Series. The study, coordinated by the ExoClock (www.exoclock.space) project, has been co-authored by 217 professional and amateur astronomers, as well as university and high school students.

"The ethos of ExoClock can be described in three key words: inclusive, interactive, and integrated. It is open to everyone and accepts contributions from amateur astronomers, students, schools and public citizens," said Anastasia Kokori, ExoClock project coordinator. "This is the third paper produced by the ExoClock team. The majority of the authors are amateur observers - around 160 - and this significant number highlights the interest and the value of the amateur community in contributing to space research."

Ariel will study a population of more than 1000 exoplanets to characterise their atmospheres. The ExoClock project, which launched in September 2019, aims to support the long-term monitoring of exoplanets through regular observations using small and medium scale telescopes.

Participants submit measurements known as 'light curves', which show the drop in intensity as a planet 'transits' or passes in front of its host star and blocks some of the light. When Ariel launches in 2029, it will need to have precise knowledge of the expected transit time of each exoplanet that it observes, in order to maximise the mission's efficiency and impact.

"The new study showed that over 40% of ephemerides for proposed Ariel targets needed to be updated. This highlights the important role that the ExoClock community can play in monitoring the Ariel targets frequently," said Tsiaras.

ExoClock participants schedule and carry out observations, analyse the data and submit their results for review and feedback from members of the science team. This interactive process helps maintain consistency in results, and enriches the experience of the participants who learn through dialogue.

The results show that small and medium sized telescopes can successfully observe ephemerides for the large majority of the Ariel candidate targets. They also show how observations by amateur astronomers using their own telescopes can contribute to real science and have a high impact for a mission. The project helps to integrate Ariel with other space missions, ground-based telescopes, literature data and wider society, making best use of all available resources.

Kokori said: "Science is for everyone, and we are very happy that through the project everyone can be part of a real space mission. Our observers come from more than 35 countries and have different backgrounds. It is wonderful to see so many people willing to learn and work together in a collaborative spirit. Our team keeps growing daily with participants from all over the world."