ARIEL homepage image


ARIEL In A Nut-shell


ARIEL is the M4 (4th medium-sized) mission in the ESA Cosmic Vision longterm plan. ARIEL was selected in March 2018 and is now in phase B1 (definition study phase). The next major milestone is Mission Adoption planned for November 2020. After succesful adoption the actual 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 F to M. The key science questions ARIEL will address are:

  • What are exoplanets made of?
  • How do planets and planetary systems form?
  • How do planets and their atmospheres evolve over time?

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 Consortium (consisting of more than 50 institutes in 17 European countries) which is responsible for the provision of the ARIEL paylod module. After launch operations will be conducted jointly by ESA (mission operations & part of the science operations) an the ARIEL Consortium (part of the science operations) with the spacecraft in a large halo orbit around L2.

Check out the presentations from the ARIEL: Science, Mission & Community 2020 conference held on 14-16 January 2020 in ESA/ESTEC, Noordwijk, The Netherlands to learn the latest on all aspects of the ARIEL mission.