The CHaracterising ExOPlanet Satellite (CHEOPS) is a mission dedicated to the search for exoplanetary transits through high precision photometry of bright stars already known to host planets. The telescope will provide the unique capability of determining accurate radii for planets whose masses have already been measured from ground-based spectroscopic surveys. This will allow a first-order characterisation of the planets' internal structure through the determination of the bulk density, providing direct insight into their composition. The CHEOPS simulator has been developed to perform detailed simulations of the data which is to be received from the CHEOPS satellite. It generates accurately simulated images that can be used to explore design options and to test the on-ground data processing, in particular, the pipeline producing the photometric time series. It is, thus, a critical tool for estimating the photometric performance expected in flight and to guide photometric analysis. It can be used to prepare observations, consolidate the noise budget, and asses the performance of CHEOPS in realistic astrophysical fields that are difficult to reproduce in the laboratory. Images generated by CHEOPSim take account of many detailed effects, including variations of the incident signal flux and backgrounds, and detailed modelling of the satellite orbit, pointing jitter and telescope optics, as well as the CCD response, noise and readout. The simulator results presented in this paper have been used in the context of validating the data reduction processing chain, in which image time series generated by CHEOPSim were used to generate light curves for simulated planetary transits across real and simulated targets. Independent analysts were successfully able to detect the planets and measure their radii to an accuracy within the science requirements of the mission.

/pdf/expected-performances-of-the-characterising-exoplanet-51ua1nterl.pdf

Expected performances of the Characterising Exoplanet Satellite (CHEOPS) II. The CHEOPS simulator

ARIEL (the Atmospheric Remote-sensing Infrared Exoplanet Large-survey) is one of the three candidates for the next
ESA medium-class science mission (M4) expected to be launched in 2026. This mission will be devoted to observing
spectroscopically in the infrared a large population of warm and hot transiting exoplanets (temperatures from ~500 K to
~3000 K) in our nearby Galactic neighborhood, opening a new discovery space in the field of extrasolar planets and
enabling the understanding of the physics and chemistry of these far away worlds. The three candidate missions for M4
are now in a Phase A study which will run until mid-2017 at which point one mission will be selected for
implementation.
ARIEL is based on a 1-m class telescope feeding both a moderate resolution spectrometer covering the wavelengths
from 1.95 to 7.8 microns, and a four channel photometer (which also acts as a Fine Guidance Sensor) with bands
between 0.55 and 1.65 microns. During its 3.5 years of operation from an L2 orbit, ARIEL will continuously observe
exoplanets transiting their host star.

An integrated payload design for the Atmospheric Remote-sensing Infrared Exoplanet Large-survey (ARIEL)

Context. The CHaracterising ExOPlanet Satellite (CHEOPS) is a mission dedicated to the search for exoplanetary transits through high precision photometry of bright stars already known to host planets. The telescope will provide the unique capability of determining accurate radii for planets whose masses have already been measured from ground-based spectroscopic surveys. This will allow a first-order characterisation of the planets’ internal structure through the determination of the bulk density, providing direct insight into their composition. By identifying 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.Aims. The CHEOPS simulator has been developed to perform detailed simulations of the data which is to be received from the CHEOPS satellite. It generates accurately simulated images that can be used to explore design options and to test the on-ground data processing, in particular, the pipeline producing the photometric time series. It is, thus, a critical tool for estimating the photometric performance expected in flight and to guide photometric analysis. It can be used to prepare observations, consolidate the noise budget, and asses the performance of CHEOPS in realistic astrophysical fields that are difficult to reproduce in the laboratory.Methods. The simulator has been implemented as a highly configurable tool called CHEOPSim, with a web-based user interface. Images generated by CHEOPSim take account of many detailed effects, including variations of the incident signal flux and backgrounds, and detailed modelling of the satellite orbit, pointing jitter and telescope optics, as well as the CCD response, noise and readout.Results. The simulator results presented in this paper have been used in the context of validating the data reduction processing chain, in which image time series generated by CHEOPSim were used to generate light curves for simulated planetary transits across real and simulated targets. Independent analysts were successfully able to detect the planets and measure their radii to an accuracy within the science requirements of the mission: for an Earth-sized planet with an orbital period of 50 days orbiting a Sun-like target with magnitude V  = 6, the median measured value of the planet to star radius ratio, R p /R s , was 0.00923 ± 0.00054(stat) ± 0.00019(syst), compared to a true input value of 0.00916. For a Neptune-sized planet with an orbital period of 13 days orbiting a target with spectral type K5V and magnitude V  = 12, the median measured value of R p /R s was 0.05038 ± 0.00061(stat) ± 0.00031(syst), compared to a true input value of 0.05.

/pdf/expected-performances-of-the-characterising-exoplanet-366puxjmvy.pdf

Expected performances of the Characterising Exoplanet Satellite (CHEOPS): II. The CHEOPS simulator

Infrared image sensor developments supported by the European Space Agency

We propose a dedicated, ultra-deep spectroscopic survey in the near infrared (NIR), that will target a mass-limited sample of galaxies during two of the most fundamental epochs of cosmic evolution: the formation of the first galaxies (at z $\gtrsim $
 6; comsmic dawn), and at the peak of galaxy formation activity (at redshift z
 $\sim $
 1–3; cosmic noon). By way of NIR observations (λ= 0.8–2μ m), it is possible to study the UV Lyman-α region in the former, and the optical rest-frame in the latter, allowing us to extract fundamental observables such as gas and stellar kinematics, chemical abundances, and ages, providing a unique legacy database covering these two crucial stages of cosmic evolution. The need to work in the NIR at extremely low flux levels makes a ground-based approach unfeasible due to atmospheric emission and absorption. Only with the largest facilities of the future (e.g. ELT) will be possible to observe a reduced set of targets, comprising at most of order thousands of galaxies. Likewise, from space, the small field of view of JWST and its use as a general purpose facility will yield a rather small set of high quality NIR spectra of distant galaxies (in the thousands, at best). Our project (codename Chronos) aims to produce $\sim $
 1 million high quality spectra, with a high S/N in the continuum, where information about the underlying stellar populations is encoded. The main science drivers are:

/pdf/chronos-a-nir-spectroscopic-galaxy-survey-to-probe-the-most-1bjsrfiyfn.pdf

Chronos: A NIR spectroscopic galaxy survey to probe the most fundamental stages of galaxy evolution

Two PLATO Teledyne-e2v CCD280 have been proton irradiated: one whilst operating at cold and the other unbiased at room temperature. We report on differences in the postirradiation hot pixel population, trap species, and charge transfer inefficiency (CTI), including after annealing. We demonstrate once more that proton irradiation performed at the charge-coupled device temperature of operation can show significant differences to the traditional room-temperature irradiation. The cold-irradiated detector shows a factor 2 greater radiation induced increase in dark current and a factor 3 to 4 greater increase in hot pixel numbers, however, the parallel CTI measured in the PLATO operating conditions is a factor 1.5 lower. Using the trap pumping technique, we provide distributions of radiation-induced trap release time constants at different temperatures, which can be used to identify the type of defects and estimate CTI in other operating conditions.

Comparative Study of Cryogenic Versus Room-Temperature Proton Irradiation of N-Channel CCDs and Subsequent Annealing

The European Space Agency has a very strong interest in the performance enhancement of detector arrays for future scientific and astronomy missions. Improvements in Visible and Infrared wavelengths are of particular interest and the Agency undertakes a programme of continuous development aimed at enhancing the capability of detectors in these wavebands. This paper presents the status of these detector technology development activities.

The status of European Space Agency supported detector developments

In the context of PLATO | ESA's exo-Earth hunting mission due for launch in 2026 | the Science Payload Validation team at ESA/ESTEC have performed a cryogenic proton irradiation and testing campaign of the PLATO CCD radiation test vehicle the Teledyne-e2v CCD280. Following the irradiation in standard conditions (room temperature, unbiased) of one device, and the irradiation of another in close to flight conditions (at T=203K and operated), the devices performance (CTI, dark current, hot pixels, trap population) were concurrently monitored over a two month period, first at a constant temperature and then following several temperature cycles. The results of these investigations will be presented.

Investigating end-of-life performance of the PLATO CCD: cryogenic versus room temperature proton irradiation comparison

PLATO is an exoplanet hunting mission of the European Space Agency. It is a medium-class mission, with a launch foreseen in 2026. Its prime objective is to uncover Earth-sized planets residing in their habitable zone. The payload consists in 26 cameras with a very wide field of view. These cameras consist in a Telescope Optical Unit, aligned at ambient and characterised at the operational temperature, and a Focal Plane Array bearing the detectors, and delivered after coupling with the Front End Electronics. In this contribution, we report on the alignment of the Engineering Model camera of Plato, i.e., the input metrology, the mechanical alignment of the optical unit with the focal plane array, the test environment and the optical characterisation throughout the process until the integrity check after delivery to the cryo-vacuum testing facility where the camera underwent a thorough performance demonstration. We also give a detailed description of the bolting process and the associated error budget.

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Yves Levillain

Papers

Comparative Study of Cryogenic Versus Room-Temperature Proton Irradiation of N-Channel CCDs and Subsequent Annealing

The status of European Space Agency supported detector developments

Investigating end-of-life performance of the PLATO CCD: cryogenic versus room temperature proton irradiation comparison

Alignment and integration of the first PLATO camera

Characterization of the response to spot illumination of the PLATO CCD