ARIEL: ESA's new exoplanet-hunting mission

The ARIEL mission will investigate the atmospheres of exoplanets. The project will be led and planned within the UK.

The ARIEL satellite will look for traces of chemicals such as water vapour, carbon dioxide and methane in exoplanet atmospheres. Image Credit: ESA/STFC RAL Space/UCL/Europlanet-Science Office
Published: March 21, 2018 at 12:00 pm
Try 3 issues for just £5 when you subscribe to BBC Sky at Night Magazine today!

A new exoplanet-investigating spacecraft, ARIEL, that will explore how distant planets form and evolve has been given the green light by the European Space Agency. The leadership and planning of ARIEL (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) spacecraft will largely be based in the UK, across several different institutions.


ARIEL will be ESA’s fourth medium-class science mission and is currently due for launch in 2028.

The four-year mission will study over 1,000 previously known exoplanets, teasing out details about their atmospheres' composition, temperature, pressure and weather.

“Although we’ve now discovered around 3,800 planets orbiting other stars, the nature of these exoplanets remains largely mysterious,” says Giovanna Tinetti of University College London, who is ARIEL’s principal investigator.

“ARIEL will study a statistically large sample of exoplanets to give us a truly representative picture of what these planets are like.

“This will enable us to answer questions about how the chemistry of a planet links to the environment in which it forms, and how its birth and evolution are affected by its parent star.”

ARIEL will study a wide range of exoplanets from Jupiter-sized bodies planets to 'super Earths'.

Most of these will closely orbit their host stars, as warmer temperatures help to keep the chemicals the team are looking for at high altitudes where ARIEL can see them, though some will lie in their star’s more temperate 'habitable zone'.

But before ARIEL can look at its first exoplanet, the spacecraft needs to be designed and built.

The project is a grand undertaking – over 60 institutes across 15 ESA member state nations are taking part in ARIEL, and the mission has a budget of €450 million.

Several UK institutions will be involved, including University College London, Cardiff University, the University of Oxford, STC Rutherford Appleton Laboratory and the Mullard Space Science Laboratory.

“The decision to select the ARIEL mission demonstrates the scientific vision and ambition of ESA, and it’s the start of a great adventure for everyone involved,” says Matt Griffin, a member of Cardiff University’s instrumentation group, which will create simulations that will help plan and interpret observations.

“The team are very excited to have the opportunity to realise the mission we’ve been developing for the last two years,” says Paul Eccleston, the ARIEL Consortium Project Manager from the STFC’s Rutherford Appleton Laboratory Space.


“It is wonderful news that ESA have selected ARIEL for the next medium class science mission.”


Ezzy Pearson is the News Editor of BBC Sky at Night Magazine. Her first book about the history of robotic planetary landers is out now from The History Press.


Sponsored content