CHaracterizing ExOPlanet Satellite

Mission Overview:

The CHEOPS mission - adopted by ESA on February 2014 - will be the first S-Class ESA Mission in partnership with Switzerland and with a number of contributing member states in the CHEOPS Consortium. It will be the first mission entirely dedicated to search for exoplanets transits through ultra-high precision photometry of stars already known to host planets. The satellite is currently (April 2019) integrated and scheduled to lift off in the launch slot 15 October 14 November 2019.

The main scientific objective is the study of the structure of exoplanets smaller than Saturn, orbiting bright stars. The current ground-based high-precision spectroscopic surveys have determined hundreds of stars hosting planets with masses in the range of 1 < Mplanet/MEarth < 20, i.e. from Super-Earth to Neptunes. Planned future ground surveys will continue to increase this sample. CHEOPS studies of planets' transits of a sample of about 500 targets, with a photometric precision of 20 ppm for a G5 star in 6 hours of integration, will allow to measure radii with a precision of 10% for Neptune sized planets and so to estimate the bulk planet densities.

The Italian contribution includes the provision of the CHEOPS Telescope, the Science Archive mirror at the ASI Science Data Center, the contribution to the preparation and fulfillment of the CHEOPS science program. The CHEOPS telescope is a very fast instrument whose design is driven by the requirement of very high precision and stable photometry, that can be reached by strongly suppress and control the straylight. CHEOPS nominal lifetime duration is 3.5 years, and 20% of the science observing time is available to the scientific community for exoplanets studies through an ESA Guest Observer's (GO) Programme. Annual Announcements of Opportunity (AO) will be solicited. The first AO, AO-1, has been opened on March 19 2019.

The primary reference for CHEOPS are CHEOPS Definition Study Report (Red Book) and the CHEOPS Observers' Manual .
A full description of the mission can be found at the following links:

Bern CSH website:
ESA website:
ESA AO-1 website:
INAF-OACT website:

Sky projection map including an example of preliminary target list, with background colors representing the expected exposure at different sky positions in 1 year operations (orange indicate the maximum value, white not covered regions).

SSDC Contribution:

On April 2014 SSDC has been adopted as a SOC partner to host an official CHEOPS Science Archive mirror, with the responsability to keep the archive updated and provide access for scientific users to public and private data. Moreover, SSDC will support the italian scientific community interested in the CHEOPS mission data.

CHaracterizing ExOPlanet Satellite

Primary goal Characterise transiting exoplanets orbiting bright host stars
Targets Known exoplanet host stars with a V-magnitude < 12.5 anywhere in the sky
Wavelength 0.4 to 1.1 µm
Orbit Sun-synchronous, 650-800 km altitude, local time of ascending node: 06:00
Lifetime 3.5 years
Type S-class mission