The CHEOPS mission
Journal article, 2021

The CHaracterising ExOPlanet Satellite (CHEOPS) was selected on October 19, 2012, as the first small mission (S-mission) in the ESA Science Programme and successfully launched on December 18, 2019, as a secondary passenger on a Soyuz-Fregat rocket from Kourou, French Guiana. CHEOPS is a partnership between ESA and Switzerland with important contributions by ten additional ESA Member States. CHEOPS is the first mission dedicated to search for transits of exoplanets using ultrahigh precision photometry on bright stars already known to host planets. As a follow-up mission, CHEOPS is mainly dedicated to improving, whenever possible, existing radii measurements or provide first accurate measurements for a subset of those planets for which the mass has already been estimated from ground-based spectroscopic surveys. The expected photometric precision will also allow CHEOPS to go beyond measuring only transits and to follow phase curves or to search for exo-moons, for example. Finally, by unveiling transiting exoplanets with high potential for in-depth characterisation, CHEOPS will also provide prime targets for future instruments suited to the spectroscopic characterisation of exoplanetary atmospheres. To reach its science objectives, requirements on the photometric precision and stability have been derived for stars with magnitudes ranging from 6 to 12 in the V band. In particular, CHEOPS shall be able to detect Earth-size planets transiting G5 dwarf stars (stellar radius of 0.9R⊙) in the magnitude range 6 ≤ V ≤ 9 by achieving a photometric precision of 20 ppm in 6 hours of integration time. In the case of K-type stars (stellar radius of 0.7R⊙) of magnitude in the range 9 ≤ V ≤ 12, CHEOPS shall be able to detect transiting Neptune-size planets achieving a photometric precision of 85 ppm in 3 hours of integration time. This precision has to be maintained over continuous periods of observation for up to 48 hours. This precision and stability will be achieved by using a single, frame-transfer, back-illuminated CCD detector at the focal plane assembly of a 33.5 cm diameter, on-axis Ritchey-Chrétien telescope. The nearly 275 kg spacecraft is nadir-locked, with a pointing accuracy of about 1 arcsec rms, and will allow for at least 1 Gbit/day downlink. The sun-synchronous dusk-dawn orbit at 700 km altitude enables having the Sun permanently on the backside of the spacecraft thus minimising Earth stray light. A mission duration of 3.5 years in orbit is foreseen to enable the execution of the science programme. During this period, 20% of the observing time is available to the wider community through yearly ESA call for proposals, as well as through discretionary time approved by ESA’s Director of Science. At the time of this writing, CHEOPS commissioning has been completed and CHEOPS has been shown to fulfill all its requirements. The mission has now started the execution of its science programme.

High-precision transit photometry

Small mission

Exoplanets

CHEOPS

Author

W. Benz

University of Bern

C. Broeg

University of Bern

A. Fortier

University of Bern

N. Rando

European Space Research and Technology Centre (ESA ESTEC)

T. Beck

University of Bern

M. Beck

University of Geneva

D. Queloz

University of Geneva

D. Ehrenreich

University of Geneva

P. Maxted

Keele University

K. Isaak

European Space Research and Technology Centre (ESA ESTEC)

N. Billot

University of Geneva

Y. Alibert

University of Bern

R. Alonso

Instituto Astrofisico de Canarias

C. António

DEIMOS Engenharia

J. Asquier

European Space Research and Technology Centre (ESA ESTEC)

T. Bandy

University of Bern

T. Bárczy

Admatis

D. Barrado

Centro de Astrobiologia (CAB)

S.C.C. Barros

University of Porto

W. Baumjohann

Institut fur Weltraumforschung

A. Bekkelien

University of Geneva

M. Bergomi

Osservatorio Astronomico di Padova

F. Biondi

Osservatorio Astronomico di Padova

X. Bonfils

Université Grenoble Alpes

L. Borsato

Osservatorio Astronomico di Padova

A. Brandeker

Stockholm University

M.-D. Busch

University of Bern

J. Cabrera

German Aerospace Center (DLR)

V. Cessa

University of Bern

S. Charnoz

Institut de Physique du Globe de Paris

B. Chazelas

University of Geneva

A. Collier Cameron

University of St Andrews

C. Corral Van Damme

European Space Research and Technology Centre (ESA ESTEC)

D. Cortes

Airbus Group

Melvyn B. Davies

Lund University

M. Deleuil

Laboratoire d'Astrophysique de Marseille

A. Deline

University of Geneva

L. Delrez

University of Liège

O. Demangeon

University of Porto

B.O. Demory

University of Bern

Anders Erikson

German Aerospace Center (DLR)

J. Farinato

Osservatorio Astronomico di Padova

L. Fossati

Institut fur Weltraumforschung

Malcolm Fridlund

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

Leiden University

D. Futyan

University of Geneva

D. Gandolfi

University of Turin

A. Garcia Munoz

Technische Universität Berlin

Michaël Gillon

University of Liège

P. Guterman

Laboratoire d'Astrophysique de Marseille

A. Gutierrez

DEIMOS Engenharia

J. Hasiba

Institut fur Weltraumforschung

Kevin Heng

University of Bern

E. Hernandez

University of Bern

S. Hoyer

Laboratoire d'Astrophysique de Marseille

L.L. Kiss

Hungarian Academy of Sciences

Z. Kovacs

Admatis

T. Kuntzer

University of Geneva

J. Laskar

Paris Observatory

A. L. des Etangs

Institut d 'Astrophysique de Paris

M. Lendl

University of Geneva

A. López

Airbus Group

I. Lora

Instituto Nacional de Tecnica Aeroespacial

C. Lovis

University of Geneva

T. Lüftinger

University of Vienna

D. Magrin

Osservatorio Astronomico di Padova

L. Malvasio

University of Bern

L. Marafatto

Osservatorio Astronomico di Padova

H. Michaelis

German Aerospace Center (DLR)

D. de Miguel

Airbus Group

D. Modrego

Instituto Nacional de Tecnica Aeroespacial

M. Munari

Osservatorio Astrofisico di Catania

Valerio Nascimbeni

University of Padua

G. Olofsson

Stockholm University

H. Ottacher

Institut fur Weltraumforschung

R. Ottensamer

University of Vienna

I. Pagano

Osservatorio Astrofisico di Catania

R. Palacios

Airbus Group

E. Palle

Instituto Astrofisico de Canarias

G. Peter

German Aerospace Center (DLR)

D. Piazza

University of Bern

Giampaolo P. Piotto

Osservatorio Astronomico di Padova

A. Pizarro

Airbus Group

D. Pollaco

The University of Warwick

Roberto Ragazzoni

Osservatorio Astronomico di Padova

F. Ratti

European Space Research and Technology Centre (ESA ESTEC)

H. Rauer

German Aerospace Center (DLR)

I. Ribas

Universitat Autonoma de Barcelona (UAB)

M. Rieder

University of Bern

R. Rohlfs

University of Bern

F. Safa

European Space Research and Technology Centre (ESA ESTEC)

M. Salatti

Agenzia Spaziale Italiana

N. C. Santos

University of Porto

Gaetano Scandariato

Osservatorio Astrofisico di Catania

D. Segransan

University of Geneva

A.E. Simon

University of Bern

Alexis M. S. Smith

German Aerospace Center (DLR)

M. Sordet

University of Geneva

S.G. Sousa

University of Porto

Manfred B. Steller

Institut fur Weltraumforschung

G.M. Szabó

Hungarian Academy of Sciences

J. Szoke

Admatis

Nicolas Thomas

University of Bern

M. Tschentscher

German Aerospace Center (DLR)

S. Udry

University of Geneva

V. Van Grootel

University of Liège

V. Viotto

Osservatorio Astronomico di Padova

I. Walter

German Aerospace Center (DLR)

N. A. Walton

University of Cambridge

F. Wildi

University of Geneva

D. Wolter

German Aerospace Center (DLR)

Experimental Astronomy

0922-6435 (ISSN) 1572-9508 (eISSN)

Vol. 51 1 109-151

Subject Categories

Aerospace Engineering

Astronomy, Astrophysics and Cosmology

Other Physics Topics

Infrastructure

Onsala Space Observatory

DOI

10.1007/s10686-020-09679-4

More information

Latest update

4/7/2021 3