PLATO - PLAnetary Transits and Oscillations of stars - is a Cosmic Vision 2015-2025 M-class mission candidate of
ESA's future Science and Robotic Exploration programme. The scientific goals are to detect exoplanetary transits and to
characterize the parent stars using astero-seismology. This is achieved through high-accuracy, high time-resolution
photometry in the visible waveband. Assessment studies were carried out for all M-class missions during 2008-2009 in
order to design a basic spacecraft configuration and identify critical areas. Following the down-selection in the beginning
of 2010, PLATO will enter into the Definition Phase, in which the spacecraft design will be consolidated and optimized.
The proposed payload will use a multi-aperture approach in which the combined observations of 34 telescopes with
individual pupil sizes of ~120 mm will produce highly accurate light curves of the target stars. Since the orbits of the
exoplanets should preferably be in or close to their habitable zone, an observation period of several years per sky field is
required to detect repeated transits of the exoplanets around the parent stars. This requires a stable spacecraft with a high
pointing accuracy and a benign operating environment. It is foreseen to launch PLATO using a Soyuz 2-1b via a direct
insertion into a large amplitude orbit around Sun-Earth L2. This paper will give an overview of the PLATO mission and
the planned activities during the Definition Phase.
PLATO is a candidate of the European Space Agency's Science programme Cosmic Vision 2015-2025. "PLAnetary
Transits and Oscillations of stars" aims to characterise exoplanetary systems by detecting planetary transits and
conducting asteroseismology of their parent stars. This is achieved through high-precision photometry (visible
waveband). PLATO is currently in assessment phase, which was started with an internal study in ESA's Concurrent
Design Facility (CDF). Two phase-A, parallel industrial studies with 12-months durations are being conducted until July
2009. The objectives of these studies are to understand the critical areas inherent to this mission and assess the trade-offs
in order to define a baseline concept that optimises scientific return while minimising complexity and risk and meeting
the applicable programmatic constraints. PLATO will operate in a large-amplitude orbit around Sun-Earth L2 where it
will observe targets for several years in order to characterise the exoplanetary transits. To observe enough stars (with
focus on Sun-like cool dwarfs) to maximize the number of transit detections, a large field-of-view (FoV) is required as
well as a sufficiently high collecting area. PLATO will achieve this objective by utilizing several smaller telescopes
instead of one large telescope. Several different optical designs, both reflective and refractive, are being studied. Due to
the large number of simultaneously observed stars the spacecraft will require a high degree of autonomy and adequate
on-board processing capability. Moreover, the stars must be monitored with high accuracy, which means that the
spacecraft must provide a stable environment in terms of pointing stability and thermal environment. This paper
summarises the results of the assessment studies.
In order to better understand the properties of exoplanetary systems, the Cosmic Vision mission "PLAnetary Transits and
Oscilliations of stars" (PLATO) will detect and characterise exoplanets using their transit signature in front of a large
sample of bright stars as well as measuring the seismic oscillations of the parent star of these exoplanets. PLATO is a
potential mission of the European Space Agency's Science programme Cosmic Vision 2015-2025, with a planned launch
by the end of 2017. The mission will be orbiting the Sun-Earth second Lagrangian point, which provides a stable thermal
environment and maximum uninterrupted observing efficiency. The payload will consist of a number of individual
catadioptric telescopes, covering a large field-of-view on the sky. It will allow for continuous observation of predetermined
star fields in order to detect many exoplanetary systems as well as smaller exoplanets with longer orbital
periods. Such performance is achieved by high time-resolution, high precision, and high duty-cycle visible photometry
using catadioptric telescopes with CCD detectors. In order to fulfill the specific science requirements, special attention is
being paid to the opto-mechanical design of the payload, in order to maximize the field-of-view and throughput of the
optical system, while minimizing the image distortion, mass and volume of each telescope to ensure compatibility with
the launcher's maximum payload capability. Ground-based observations will complement the observations made by
PLATO to allow for further exoplanetary characterization. The paper provides a summary of the preliminary results
achieved by the ESA internal pre-assessment study.
Astrobiology is a new discipline that promises to answer one of mankind's so-called 'great questions', that is whether we
are alone in the Universe. In order to do so, new technologies are required since the key element is to detects signs of life
- biomarkers - at interstellar distances. If we are going to be able to do so from the ground or if we will have to deploy
instruments in space is still somewhat un-clear. The issue is complex, and at the heart of the matter is the question of
which wavelengths will be suitable.
The Darwin and TPF-I space missions will be able to study the atmosphere of distant worlds similar to the Earth.
Flying these space-based interferometers will however be an extraordinary technological challenge and a first step
could be taken by a smaller mission. Several proposals have already been made in this context, using the simplest
nulling scheme composed of two collectors, i.e., the original Bracewell interferometer. Two of these projects, viz.
Pegase and the Fourier-Kelvin Space Interferometer, show very good perspectives for the characterisation of hot
extra-solar giant planets (i.e., Jupiter-size planets orbiting close to their parent star). In this paper, we build on
these concepts and try to optimise a Bracewell interferometer for the detection of Earth-like planets. The major
challenge is to efficiently subtract the emission of the exo-zodiacal cloud which cannot be suppressed by classical
phase chopping techniques as in the case of multi-telescopes nulling interferometers. We investigate the potential
performance of split-pupil configurations with phase chopping and of OPD modulation techniques, which are
good candidates for such a mitigation. Finally, we give a general overview of the performance to be expected
from space-based Bracewell interferometers for the detection of extra-solar planets. In particular, the prospects
for known extra-solar planets are presented.
A brief overview of the Darwin project in the context of the European Space Agency's Cosmic Vision program is given. The scientific goals in the context of the new approach with themes, is given. The goals are broken down into a stepwise approach first relating current ground based and immediate space based experiments (e.g. radial velocity measurements from the ground and the CNES/ESA COROT occultation mission). Then, the different approaches to how to achieving the full goal of a survey of the nearest stars is described. Then, a brief outline of steps following after the current objectives of Darwin have been reached will follow. Some focus is also given to the response of the European community on how to address these goals in a timely and technically correct fashion. This will lead up to scenarios likely to occur over the next 3 years. Darwin is developed through an active technology program, parts of which are described in other papers at this conference. A description of where the different elements fit will be given. Finally the international aspects as currently foreseen are presented.
We have conducted an exhaustive inventory of potential astrophysical "noise sources" with respect to the detection and characterisation of Earth-like planets, focusing on the specifics of the nulling interferometry technique. We have extrapolated their characterisation at these yet-to-be-attained resolution and sensitivity, from existing data and models. They range from stellar features and significant orbital motion of pegasides during exposure, to exozodiacal cloud structures, background galaxies and galactic cirrus emission. This enabled us to evaluate the offset between the various features a typical interferometric nulling field-of-view (FOV) is likely to exhibit in reality, and the simplified, planet-only, detection FOV model generally used. This work is complementary to precise nulling data model formalization and detection algorithms development (Thiebaut et al., this conference), together conducted in the frame of an ESA contract by an Alcatel Alenia Space-led consortium. As such, part of this work is under embedment into a Java open-source simulator (ORIGIN). This approach can be useful for less signal-entangling, direct imaging techniques.
Darwin is a mission under study by the European Space Agency, ESA. The mission objectives are detection
and characterization of exo-planets, with special emphasize on the planets likely to harbour earthlike life.
The mission cancels the light from the target star by nulling interferometry, while the light collected from
any orbiting planets will interfere constructively. In this way absorption features in the planetary light can
be detected and analysed. In the preceding years ESA has developed the required technology and elaborated
on and evaluated different mission concepts with the aim of reducing over-all mission cost. This has
resulted in a number of mission architectures, and various interferometric beam recombination techniques.
To consolidate the study results two parallel mission assessment studies were initiated September 2005,
taking benefit from the large number of technology developments as conducted since 2000. This article
reviews the Darwin mission and its architecture evolution from the feasibility study up to the currently
ongoing system assessment studies.
The prime objective of GENIE (Ground-based European Nulling Interferometry Experiment) is to obtain experience with the design, construction and operation of an IR nulling interferometer, as a preparation for the DARWIN / TPF mission. In this context, the detection of a planet orbiting another star would provide an excellent demonstration of nulling interferometry. Doing this through the atmosphere, however, is a formidable task. In this paper we assess the prospects of detecting with nulling interferometry on ESO's VLTI, low-mass companions in orbit around their parent stars. With the GENIE science simulator (GENIEsim) we can model realistic detection scenarios for the GENIE instrument operating in the VLTI environment, and derive detailed requirements on control-loop performance, IR background subtraction and the accuracy of the photometry calibration. We analyse the technical feasibility of several scenarios for the detection of low-mass companions in the L'-band.
Darwin is one of the most challenging space projects ever considered by the European Space Agency (ESA). Its principal objectives are to detect Earth-like planets around nearby stars and to characterise their atmospheres. Darwin is conceived as a space "nulling interferometer" which makes use of on-axis destructive interferences to extinguish the stellar light while keeping the off-axis signal of the orbiting planet. Within the frame of the Darwin program, the European Space Agency (ESA) and the European Southern
Observatory (ESO) intend to build a ground-based technology demonstrator called GENIE (Ground based European Nulling Interferometry Experiment). Such a ground-based demonstrator built
around the Very Large Telescope Interferometer (VLTI) in Paranal will
test some of the key technologies required for the Darwin Infrared Space Interferometer. It will demonstrate that nulling interferometry can be achieved in a broad mid-IR band as a precursor to the next phase of the Darwin program. The instrument will operate in the L' band around 3.8 μm, where the thermal emission from the telescopes and the atmosphere is reduced. GENIE will be able to operate in two different configurations, i.e. either as a single Bracewell nulling interferometer or as a double-Bracewell nulling interferometer with an internal modulation scheme.
The Darwin and Terrestrial Planet Finder missions, represent the European Space Agency (ESA) and NASA's interest in ultimately searching for and when found studying planets similar to the Earth-like planets in our own Solar System. As such they may be technologically very challenging space missions but recent developments points towards robust solutions. In this talk, we compare the technologies, the available solutions, and the current status in both projects. We put the emphasis on the optical technologies required, and address both main possibilities considered for planet finding, i.e. a nulling interferometer and a coronograph. We outline the strategies for selecting the appropriate technology for each element of the missions. Finally we also address the synergy in the technologies required for other missions, as well as other applications except purely scientific.
The IR Space Interferometer Darwin is an integral part of ESA's Cosmic Vision 2020 plan, intended for a launch towards the middle of next decade. It has been the subject of a feasibility study and is now undergiogn technological development. The scientific scope is aimed towards developing a system that could carry out the search for, and characterization of Earth-like planets orbiting other stars. A secondary objective is to carry out imaging of astrophysical objects with unprecedented spatial resolution. The implementation of Darwin is based on the new technique of 'nulling interferometery', in the mid-IR and becomes the culmination of a decade of technology- and science precursor missions. Darwin is also foreseen to be carrie dout in an international context.
Darwin is one of the most challenging space projects ever
considered by the European Space Agency (ESA). Its principal
objectives are to detect Earth-like planets around nearby stars and to characterize their atmospheres. Darwin is conceived as a space
"nulling interferometer" which makes use of on-axis destructive
interferences to extinguish the stellar light while keeping the
off-axis signal of the orbiting planet. Within the frame of the Darwin program, the European Space Agency (ESA) and the European Southern Observatory (ESO) intend to build a ground-based technology
demonstrator called GENIE (Ground based European Nulling
Interferometry Experiment). Such a ground-based demonstrator built
around the Very Large Telescope Interferometer (VLTI) in Paranal will
test some of the key technologies required for the Darwin Infrared Space Interferometer. It will demonstrate that nulling interferometry can be achieved in a broad mid-IR band as a precursor to the next phase of the Darwin program. The present paper will describe the objectives and the status of the project.
The closing years of the 20th century have allowed us, for the first time, to seriously discuss interferometric instruments deployed in space. With the express purpose of achieving unprecedented spatial resolution, these missions will lead to new astrophysics. Especially--and most challengely--we expect the carrying out of the first search for terrestrial exoplanets. The detection and study of the latter promises to usher in a new era in science and will affect a broad spectrum of science and technology. Further, the time line for implementation of such instruments is such that it is probably less than 5 - 10 years until we have results from them.
Darwin was proposed in 1993 to the European Space Agency as a mid-IR (5-30 micron) interferometry observatory with baselines greater than 50 meters. It would be a long-duration general purpose radiatively cooled observatory, to be launched in the 2009-2018 timeframe. Since then ESA has started a study of such a mission, called the Infrared Space Interferometer (IRSI), as one of its candidate Cornerstone missions in its Horizons 2000 plan. This paper describes some of the aspects of the Darwin concept as presently conceived by the members of the Darwin Informal Team. This team is comprised of the original proposal authors and a number of additional persons.