ARIEL (Atmospheric Remote-sensing InfraRed Large-survey) is a medium-class mission of the European Space
Agency, part of the Cosmic Vision program, whose launch is foreseen by early 2029. ARIEL aims to study the
composition of exoplanet atmospheres, their formation and evolution. The ARIEL’s target will be a sample
of about 1000 planets observed with one or more of the following methods: transit, eclipse and phase-curve
spectroscopy, at both visible and infrared wavelengths simultaneously. The scientific payload is composed by a
reflective telescope having a 1m-class elliptical primary mirror, built in solid Aluminium, and two focal-plane
instruments: FGS and AIRS.
FGS (Fine Guidance System)1 has the double purpose, as suggested by its name, of performing photometry
(0.50-0.55 µm) and low resolution spectrometry over three bands (from 0.8 to 1.95 µm) and, simultaneously,
to provide data to the spacecraft AOCS (Attitude and Orbit Control System) with a cadence of 10 Hz and
contributing to reach a 0.02 arcsec pointing accuracy for bright targets.
AIRS (ARIEL InfraRed Spectrometer) instrument will perform IR spectrometry in two wavelength ranges:
between 1.95 and 3.9 µm (with a spectral resolution R > 100) and between 3.9 and 7.8 µm with a spectral
resolution R > 30. This paper provides the status of the ICU (Instrument Control Unit), an electronic box whose purpose is to
command and supply power to AIRS (as well as acquire science data from its two channels) and to command
and control the TCU (Telescope Control Unit)
