ARIEL (space telescope)

ARIEL
Type:	Space telescope
Operator:	ESA
Mission dates
Dimensions:	≈ 1300 kg
Begin:	2028 (planned)
Starting place:	Guiana Space Center ELA-4
Launcher:	Ariane 62
Status:	in planning
Orbit data
Orbit:	Halo orbit around the sun-earth L 2 point

The Atmospheric Remote-sensing Infrared Exoplanet Large-survey ( ARIEL ) is a planned space telescope and the fourth medium-sized mission (M4) as part of the Cosmic Vision 2015–2025 program of the European Space Agency (ESA). The telescope is to be launched on an Ariane 62 together with the Comet Interceptor comet probe in 2028 . ARIEL is to use the transit method to investigate the atmospheres of around 1000 exoplanets .

Goals and structure

Precise spectroscopy of the combined light of an exoplanet and the star it orbits, during and outside of mutual eclipses (transits), makes it possible to go from the discovery of exoplanets to the determination of the chemical composition and structure of their atmospheres. The infrared spectral range , which shows the signatures of important atmospheric molecules, is well suited for this . After initial results with the Spitzer Space Telescope and the Hubble Space Telescope , this will also be an important task (of several) for the James Webb Space Telescope . With a much smaller telescope, ARIEL will not be able to compete with the sensitivity of the JWST, but can use its instruments, which have been optimized for exoplanet studies, and all of its observation time to obtain information on a large number of mainly hot exoplanets.

The ARIEL telescope will have an elliptical main mirror of 1.1 m × 0.7 m, which will be passively cooled to about 55 K by radiation. This enables sensitive spectroscopy in the infrared up to a wavelength of 7.8 µm. In addition, photometry of exoplanet transits in visible light is obtained. ARIEL is to be put into orbit around Lagrangian point L2 , about 1.5 million kilometers behind Earth when viewed from the sun.

History of the project

A similar project, Exoplanet Characterization Observatory (EChO) , had already been proposed for ESA's M3 launch opportunity , but was ultimately not selected. A modified and simplified design was then successful as the ARIEL for the M4 launch opportunity.

Web links

• ARIEL project website
• ARIEL at ESA

Individual evidence

1. ↑ ARIEL - Spacecraft , ESA, accessed September 13, 2019
2. ↑ ARIEL on the ESA website, accessed June 19, 2019.
3. ↑ esa.int: ARIEL Operations
4. ↑ ESA: ESA's Next Science Mission To Focus On Nature of Exoplanets. March 21, 2018, accessed on July 16, 2019 .