ARIEL
| Names | Atmospheric Remote-sensing Infrared Exoplanet Large-survey |
|---|---|
| Mission type | Space telescope |
| Operator | European Space Agency |
| Website | esa.int: Ariel arielmission |
| Mission duration | 4 years (planned) |
| Spacecraft properties | |
| Launch mass | 1,300 kg (2,900 lb) |
| Dry mass | 1,000 kg (2,200 lb) |
| Payload mass | 300 kg (660 lb) |
| Start of mission | |
| Launch date | 2031 (planned) |
| Rocket | Ariane 62 |
| Launch site | Guiana Space Centre, Kourou, ELA-4 |
| Contractor | Arianespace |
| Orbital parameters | |
| Reference system | Sun–Earth L2 orbit |
| Main Cassegrain reflector | |
| Diameter | 1.1 × 0.7 m |
| Focal length | f/13.4 |
| Collecting area | 0.64 m2 |
| Wavelengths | visible and near-infrared |
| Instruments | |
| Telescope assembly (TA) Ariel infrared spectrometer (AIRS) Fine Guidance System (FGS) | |
Ariel mission insignia | |
Ariel (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) is a planned space telescope and the fourth medium-class mission of the European Space Agency's Cosmic Vision programme. The mission is aimed at observing at least 1,000 known exoplanets using the transit method, studying and characterising the planets' chemical composition and thermal structures. Compared to the James Webb Space Telescope, Ariel will be a much smaller telescope with more observing time available for planet characterisation. Ariel was expected to be launched in 2029 aboard an Arianespace Ariane 6 together with the Comet Interceptor into the Sun-Earth Lagrange point L2. However as of January 2026, it is likely to be delayed until 2031.