ARIEL

Ariel will observe 1000 planets orbiting distant stars and make the first large-scale survey of the chemistry of exoplanet atmospheres.{{cite web|url=https://ariel-spacemission.eu/press-releases/|title=A Candidate for the ESA M4 Mission|archive-url=https://web.archive.org/web/20190421085430/https://ariel-spacemission.eu/press-releases/|archive-date=2019-04-21|publisher=Ariel Space Mission |date=21 April 2019|access-date=12 June 2021}} The objective is to answer fundamental questions about how planetary systems form and evolve.{{cite web |url=https://arielspacemission.files.wordpress.com/2018/03/ariel-selection-press-release-uk_2018_final_updated.pdf|title=Ariel exoplanet mission selected as ESA's next medium-class science mission |publisher=Ariel Space Mission|date=20 March 2018|access-date=12 June 2021}} A spectrometer will spread the light into a spectrum ("rainbow") and determine the chemical fingerprints of gases in the planets' atmospheres. This will enable scientists to understand how the chemistry of a planet links to the environment in which it forms, and how its formation and evolution are affected by its parent star. ARIEL will study a diverse population of exoplanets in a wide variety of environments, but it will focus on warm and hot planets in orbits close to their star.

The Ariel mission is being developed by a consortium of various institutions from eleven member states of the European Space Agency (ESA),{{efn|These are the University of Vienna from Austria, the Universities of Leuven and Liège from Belgium, the Technical University of Denmark, the CEA, CNES, Paris Institute of Astrophysics, Marseille, Côte d'Azur, and Paris Observatories in France, the Max Planck Society and University of Hamburg in Germany, SRON and the Universities of Amsterdam, Delft, and Leiden in the Netherlands, the Space Research Centre of Polish Academy of Sciences, the CAB, Institute of Space Sciences and the Institute of Astrophysics of the Canary Islands in Spain, University of Bern in Switzerland, and the ATC and the Universities of Cardiff, Exeter, Hertfordshire, Keele, Leicester, London, and Oxford in the United Kingdom.{{cite web|title=(ESA/SCI(2017)2) ARIEL – Atmospheric Remote-sensing Infrared Exoplanet Large-survey -- Enabling Planetary Science across Light-years|url=https://arielspacemission.files.wordpress.com/2017/05/sci-2017-2-ariel.pdf|publisher=ARIEL Science Mission |archive-url=https://web.archive.org/web/20180322214222/https://arielspacemission.files.wordpress.com/2017/05/sci-2017-2-ariel.pdf|archive-date=22 March 2018|date=March 2017|access-date=12 June 2021}}}} and international contributors from four countries.{{efn|These are the Université de Montréal and the University of Toronto in Canada, the ELSI, Tokyo Institute of Technology, and Osaka University in Japan, the National Autonomous University of Mexico, and Caltech, the Lunar and Planetary Laboratory (LPL) and Jet Propulsion Laboratory (JPL), Lunar and Planetary Institute, and Universities of Arizona State, Chicago, and Princeton in the United States.}} The project is led by principal investigator Giovanna Tinetti of the University College London,{{cite web |last=Amos|first=Jonathan|title=Discovering the nature of planets|url=https://www.bbc.com/news/av/science-environment-43477355/discovering-the-nature-of-planets|publisher=BBC News|access-date=22 March 2018 |archive-url=https://web.archive.org/web/20180322221849/http://www.bbc.com/news/av/science-environment-43477355/discovering-the-nature-of-planets|archive-date=22 March 2018|date=20 March 2018}}{{cite journal|last=Gibney|first=Elizabeth|title=First space mission dedicated to exoplanet atmospheres gets green light|journal=Nature |date=20 March 2018|volume=555 |issue=7698 |page=571 |doi=10.1038/d41586-018-03445-5 |bibcode=2018Natur.555..571G |doi-access=free}} who had previously led the unsuccessful Exoplanet Characterisation Observatory (EcHO) proposal for the M3 Cosmic Vision launch slot.{{cite journal|last=Gewin|first=Virginia |title=Turning point: Giovanna Tinetti|journal=Nature |date=14 April 2011|volume=472|issue=7342|page=251|doi=10.1038/nj7342-251a|issn=1476-4687|doi-access=free}}{{cite web|author=European Space Agency|title=ESA selects planet-hunting PLATO mission|url=http://www.astronomy.com/news/2014/02/esa-selects-planet-hunting-plato-mission|publisher=Astronomy (magazine)|access-date=22 March 2018|archive-url=https://web.archive.org/web/20180322221837/http://www.astronomy.com/news/2014/02/esa-selects-planet-hunting-plato-mission|archive-date=22 March 2018|date=21 February 2014}} Operations of the mission and the spacecraft will be handled jointly by ESA and the consortium behind the mission's development, through a coordinated Instrument Operations and Science Data Centre (IOSDC). A Mission Operations Centre (MOC) will be set up at the European Space Operations Centre (ESOC) in Darmstadt, Germany, while a concurrent ARIEL Science Operations Centre (SOC) will be set up at the European Space Astronomy Centre (ESAC) near Madrid, Spain. The MOC will be responsible for the spacecraft itself, while the SOC will be responsible for archiving mission data and scientific data downlinked from the spacecraft. The IOSDC will help develop results from the mission based on data received by the SOC.

In August 2017, NASA conditionally selected Contribution to ARIEL Spectroscopy of Exoplanets (CASE) as a Partner Mission of Opportunity, pending the result of ESA's Cosmic Vision selection.{{cite web|title=NASA Selects Proposals to Study Galaxies, Stars, Planets|url=https://www.jpl.nasa.gov/news/news.php?feature=6918|work=Jet Propulsion Laboratory|publisher=NASA|access-date=28 April 2018}} {{PD-notice}} Under the proposal NASA provides two fine guidance sensors for the ARIEL spacecraft in return for the participation of U.S. scientists in the mission.{{cite web|title=FINESSE and ARIEL + CASE: Dedicated Transit Spectroscopy Missions for the Post-TESS Era |url=https://cor.gsfc.nasa.gov/copag/AAS_Jan2018/bean_finesse_case.pdf|work=Cosmic Origins Program Analysis Group (COPAG)|publisher=NASA|access-date=28 April 2018}} {{PD-notice}} CASE was officially selected in November 2019, with JPL astrophysicist Mark Swain as principal investigator.{{cite web|last=Landau|first=Elizabeth|url=https://www.nasa.gov/feature/jpl/nasa-instrument-to-probe-planet-clouds-on-european-mission|title=NASA Instrument to Probe Planet Clouds on European Mission|publisher=NASA|date=8 November 2019|access-date=12 November 2019}} {{PD-notice}}

On December 7, 2021, ESA announced that the €200 million contract to build Ariel had been awarded to Airbus Defence and Space.{{cite web|title=ESA award €200m contract to Airbus to build Ariel observatory|date=7 December 2021 |url=https://europeanspaceflight.com/esa-award-e200m-contract-to-airbus-to-build-ariel-observatory/|publisher=European Spaceflight|access-date=7 December 2021}}

On December 6, 2023, ESA approved the construction of Ariel with a targeted launch date of 2029. {{cite web|title=ESA's Ariel Mission is Approved to Begin Construction|date=6 December 2023 |url=https://www.universetoday.com/164655/esas-ariel-mission-is-approved-to-begin-construction/|access-date=6 December 2023}}

The design of the ARIEL spacecraft is based on that intended for the Exoplanet Characterisation Observatory (EChO) mission, and has heritage from the thermal design of Planck.{{cite web|title=ARIEL: Spacecraft|url=http://sci.esa.int/ariel/59800-spacecraft/|publisher=European Space Agency|access-date=22 March 2018|archive-url=https://archive.today/20180322044912/http://sci.esa.int/ariel/59800-spacecraft/|archive-date=22 March 2018|date=20 March 2018|url-status=live}} The body of the spacecraft is split into two distinct modules known as the Service Module (SVM) and the Payload Module (PLM). The PLM will complete its Assembly, Integration and Test (AIT) at RAL Space, STFC. The PLM consists of three aluminium V-Grooves and three pairs of low conductivity fibreglass bipod struts supporting the PLM. A basic horizontal telescope (see next section) configuration is used for the PLM itself, housing all of the spacecraft's scientific instruments and its oval {{cvt|1.1 × 0.7|m}} primary mirror.{{cite web|title=Facts & Figures|url=https://ariel-spacemission.eu/ariel-media/|publisher=ARIEL Space Mission|date=May 2017 |access-date=22 March 2018|archive-url=https://web.archive.org/web/20180322054107/https://ariel-spacemission.eu/ariel-media/|archive-date=22 March 2018}} At launch, the spacecraft will have a fuelled mass of {{cvt|1300|kg}}, and will have a dry mass of {{cvt|1000|kg}}. The PLM will account for around {{cvt|300|kg}} of that mass.

The Ariel telescope's assembly is an off-axis Cassegrain telescope followed by a third parabolic mirror to recollimate the beam. The telescope uses an oval {{cvt|1.1 × 0.7|m}} primary mirror; the imaging quality of the system is limited by diffraction for wavelengths longer than about 3 μm, and its focal ratio (f) is 13.4.[http://sci.esa.int/ariel/59801-payload/ ARIEL - Payload] ESA, 20 March 2018 The system will acquire images in the visible and near-infrared spectrum. The near-infrared sensor and its front-end driver board, is the same of Euclid.NISP instrument. To operate its infrared spectroscope between 1.95 μm and 7.8 μm, the telescope will be cooled to a temperature of {{cvt|55|K}}.

The Ariel spacecraft is expected to be launched in 2029 by Arianespace's Ariane 62 launch vehicle (currently in development{{cite web|last=Amos|first=Jonathan|title=Full thrust on Europe's new Ariane 6 rocket |url=https://www.bbc.com/news/science-environment-40366736|publisher=BBC News|access-date=22 March 2018|archive-url=https://web.archive.org/web/20180322110946/http://www.bbc.com/news/science-environment-40366736|archive-date=22 March 2018|date=22 June 2017}}{{cite web|last=Pultarova |first=Tereza|title=ArianeGroup CFO Pierre Godart on Ariane 6 cost savings, micro launchers and reusability|url=http://spacenews.com/arianegroup-cfo-pierre-godart-on-ariane-6-cost-savings-micro-launchers-and-reusability/|publisher=SpaceNews|access-date=22 March 2018|archive-url=https://archive.today/20180322112321/http://spacenews.com/arianegroup-cfo-pierre-godart-on-ariane-6-cost-savings-micro-launchers-and-reusability/|archive-date=22 March 2018|date=25 October 2017|url-status=live}}) together with the Comet Interceptor.{{cite web |url=https://www.esa.int/Science_Exploration/Space_Science/Ariel_moves_from_blueprint_to_reality|title=Ariel moves from blueprint to reality|publisher=ESA|date=12 November 2020|access-date=12 June 2021}}{{cite web|title=ESA's next science mission to focus on nature of exoplanets|url=http://sci.esa.int/cosmic-vision/59796-esa-s-next-science-mission-to-focus-on-nature-of-exoplanets/ |series=ESA Science & Technology Portal|publisher=European Space Agency|access-date=22 March 2018|archive-url=https://archive.today/20180322105424/http://sci.esa.int/cosmic-vision/59796-esa-s-next-science-mission-to-focus-on-nature-of-exoplanets/|archive-date=22 March 2018|date=20 March 2018|url-status=live}}{{cite web|last=Warren|first=Melissa|title=UK part of Ariel exoplanet project selected as ESA's next medium-class science mission|url=https://www.stfc.ac.uk/news/uk-part-of-ariel-exoplanet-project/|publisher=Science and Technology Facilities Council|access-date=22 March 2018|archive-url=https://web.archive.org/web/20180322105041/https://www.stfc.ac.uk/news/uk-part-of-ariel-exoplanet-project/|archive-date=22 March 2018|date=20 March 2018}} It will be launched from the Centre Spatial Guyanais (CSG) in Kourou, French Guiana, from the "Ensemble de lancement Ariane" ELA-4 (Ariane Launch Area-4) being purpose-built for future Ariane 6 launches.{{cite web|title=Race to build Ariane 6 rocket launch pad|url=http://www.euronews.com/2017/12/14/race-to-build-ariane-6-rocket-launch-pad|publisher=Euronews|access-date=22 March 2018|archive-url=https://web.archive.org/web/20180322110944/http://www.euronews.com/2017/12/14/race-to-build-ariane-6-rocket-launch-pad|archive-date=22 March 2018|date=14 December 2017}} Ariel will be launched to the L₂ Lagrange point, in a position located at a distance of {{cvt|1500000|km}} from Earth, where it will encounter a very stable thermal environment that is required to detect exoplanets.

{{Portal|Astronomy|Spaceflight}}

• CHEOPS and PLATO – Cosmic Vision exoplanetology missions
• Fast Infrared Exoplanet Spectroscopy Survey Explorer (FINESSE) – was a mission proposal (cancelled) to NASA equivalent to ARIEL
• Comet Interceptor – launching on the same launch vehicle
• List of space telescopes

{{Notelist|30em}}

{{Reflist}}

• [https://ariel-spacemission.eu ARIEL] {{Webarchive|url=https://web.archive.org/web/20180330122940/https://ariel-spacemission.eu/|date=30 March 2018}} official website
• [http://sci.esa.int/ariel/ ARIEL] at the European Space Agency

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{{Exoplanet search projects}}

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{{Future spaceflights}}

Category:2029 in spaceflight

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