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.
Exoplanets
Small mission
CHEOPS
High-precision transit photometry
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 de Astrofísica 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
Istituto nazionale di astrofisica (INAF)
F. Biondi
Istituto nazionale di astrofisica (INAF)
X. Bonfils
Grenoble Alpes University
L. Borsato
Istituto nazionale di astrofisica (INAF)
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
Istituto nazionale di astrofisica (INAF)
L. Fossati
Institut fur Weltraumforschung
Malcolm Fridlund
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
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
Istituto nazionale di astrofisica (INAF)
L. Malvasio
University of Bern
L. Marafatto
Istituto nazionale di astrofisica (INAF)
H. Michaelis
German Aerospace Center (DLR)
D. de Miguel
Airbus Group
D. Modrego
Instituto Nacional de Tecnica Aeroespacial
M. Munari
Istituto nazionale di astrofisica (INAF)
Valerio Nascimbeni
University of Padua
G. Olofsson
Stockholm University
H. Ottacher
Institut fur Weltraumforschung
R. Ottensamer
University of Vienna
I. Pagano
Istituto nazionale di astrofisica (INAF)
R. Palacios
Airbus Group
E. Palle
Instituto de Astrofísica de Canarias
G. Peter
German Aerospace Center (DLR)
D. Piazza
University of Bern
Giampaolo P. Piotto
Istituto nazionale di astrofisica (INAF)
A. Pizarro
Airbus Group
D. Pollaco
The University of Warwick
Roberto Ragazzoni
Istituto nazionale di astrofisica (INAF)
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
Istituto nazionale di astrofisica (INAF)
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
Istituto nazionale di astrofisica (INAF)
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 1 109-151Subject Categories
Aerospace Engineering
Astronomy, Astrophysics and Cosmology
Other Physics Topics
Infrastructure
Onsala Space Observatory
DOI
10.1007/s10686-020-09679-4