ARIEL homepage image


ARIEL In A Nut-shell​​​



5 December 2023: 

Ariel, ESA’s mission to identify the chemical elements in exoplanetary atmospheres, successfully passed the spacecraft preliminary design phase and now moves from the ‘drawing board’ to the construction phase. Read more at in our Press release and in our new Ariel pages. Congratulations to all teams! 


A lovely poem we would like to share has been composed by Maxsim Pudney (Airbus) following this achievement just before Christmas: 



Great congratulations to all, for PDR success!
Now everyone has worked so hard, enjoy a Christmas rest!

And just imagine Christmases on some far exo-planet,
that Ariel might find someday if it would get to scan it.

By good fortune many planets cross in front of their star,
and our dear spacecraft will observe their passing from afar.

But what makes up their atmospheres, what processes evolve?
What mysteries lie waiting that, you, Ariel will solve?

From rocky types, transitional, to gas giants and more,
a plethora of planets now seen like never before.

Observing thermal gradients, exo-cartography,
even starlight reflecting clouds your eye will strain to see.

Some water worlds may dash before your near infrared gaze,
Or puffy atmospheres proudly present their billowed haze.

Some planets abundant, sub-Neptune and super-Earth,
will show their spectral colours and reveal their hidden worth.

Some planets rare, with orbital high eccentricity,
or places far, exotic, like a circumbinary.

Calmly nestled in your V-Grooves, safe from the raging Sun,
your telescope will cooly watch each planetary run.

And who knows WHAT celebrations are taking place below?
Do aliens construct themselves from their own winter's snow?

Do they, too, gaze into the night, and wonder what is here?
And launch their own spectrometers to have a distant peer?

Remember every day the launch gets closer, more unfurled,
and with it greater insight of each miraculous world.

Merry Christmas!



Successful Ariel preliminary design review: Ariel, ESA’s next-generation mission to observe the chemical makeup of distant exoplanets, has passed a major milestone! The successful completion of the payload PDR marks a crucial step forward for Ariel, demonstrating that the mission's payload design meets all the required technical and scientific specifications, and no holdups were found for the foreseen launch in 2029. 

Please see the ESA and the Consortium news release and read more about Ariel here and here


ESA and Airbus have signed a contract to move forward with the design and construction of the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, Ariel, planned for launch in 2029

See the news release: Airbus will build ESA’s Ariel exoplanet satellite .


Ariel adoption: The ESA Science Programme Committee (SPC) has adopted Ariel in the meeting held on 12 November 2020. The mission adoption was the last study phase milestone before proceeding to mission implementation.

See the news release: Ariel moves from blueprint to reality.

Ariel is the M4 (4th medium-sized) mission in the ESA Cosmic Vision longterm plan. Ariel was selected in March 2018 and has now completed phase B1 (the definition study phase). The final study phase milestone was Mission Adoption achieved on 12 November 2020. After the succesful adoption the actual mission implementation will commence in 2021, with a planned launch by an Ariane 62 launcher in 2029 for a nominal 4 year mission, with a possible extension to 6 years.

The objective of Ariel is to perform a chemical sensus of a large (of order 1000) well selected diverse sample of primarily warm and hot exoplanets orbiting relatively nearby host stars with a range of spectral types from A to M. The key science questions Ariel will address are:

  • What are the physical processes shaping planetary atmospheres?
  • What are exoplanets made of?
  • How do planets and planetary systems form and evolve?

The target selection will be made before launch based on ESA science team and community inputs, and can be updated throughout the mission. The mission will deliver a homogeneous catalogue of planetary spectra, yielding refined molecular abundances, chemical gradients and atmospheric structure; diurnal and seasonal variations; presence of clouds and measurement of albedo.

Ariel will perform observations in three photometric bands (0.5-0.6 micron, 0.6-0.8 micron, and 0.8-1.1 micron) and three spectroscopic bands (1.1-1.95 micron (R>15), 1.95-3.9 micron (R>100), and 3.9-7.8 micron (R>30)) simultaneously covering the 0.5-7.8 micron spectral range, with an off-axis Cassegrain telescope having a 1.1x0.7 m primary providing a collecting area of 0.61 m2.

Ariel is a collaboration between ESA and the Ariel Mission Consortium (AMC - consisting of more than 50 institutes in 17 European countries and with NASA/JPL participation) which is responsible for the provision of the entire Ariel paylod module. After launch operations will be conducted jointly by ESA (mission operations & part of the science operations) an the AMC (part of the science operations) with the spacecraft in a large halo orbit around L2.

All aspects of the Ariel mission as adopted on 12 November 2020 are described in detail in the Red Book, which is available on the Documents and Articles webpage together with additional material.

Also, check out the presentations from the ARIEL: Science, Mission & Community 2020 conference held on 14-16 January 2020 in ESA/ESTEC, Noordwijk, The Netherlands.