ESA Science & Technology - Publication Archive

Reference: ECHO-SRE-SA-PHASEA-010, Issue 2

A Design Reference Mission, hereafter the EChO Core Survey, has been constructed for the Exoplanet Characterisation Observatory in order to determine the mission lifetime required to fulfil the science requirements. The EChO science requirements call for the observation of at least 100 exoplanets of diverse type and environment to provide a “Chemical Census” of exoplanet atmospheres. A proportion of these are required to be observed at high signal to noise ratio to provide an Origin sample and “Rosetta Stones” giving a deeper understanding of the physics and chemistry of their atmospheres. Two target samples lists have been derived: one using catalogues of real targets as known today, and a second using a statistical approach to predict how many targets will be available by the time EChO is operational in the 2020’s. These lists have been evaluated using mission performance models to test the observing time required to fulfil the EChO Core Survey. We find that a nominal mission lifetime of four years is sufficient to fulfil the science requirements and a mission of six years will fulfil the ambitious goals for EChO. The use of separate target lists and performance models gives confidence that the Core Survey can be undertaken within the mission lifetime and that will result in a revolution in understanding the origin and evolution of planets.

Reference: SRE-PA/2011.040/, Issue 3, Revision 2

This document provides a detailed description of the ESA EChO radiometric model. This model will be used to validate the mission requirements, which have, in turn, been derived from the science requirements. The model provides the means to calculate, for a given host star/exoplanet target:

• The SNR that can be achieved in a single primary transit
• The SNR that can be achieved in a single occultation
• The number of transit/occultation revisits necessary to achieve a specified SNR
• The total number of revisits that could be achieved during the proposed mission lifetime.

The radiometric model will be used to establish whether proposed samples of known or model targets can be observed to the signal-to-noise ratio (SNR) called for in the Science Requirements Document, with mission requirements given in the Mission Requirements Document (i.e. within the mission lifetime, with the observation efficiency required and the minimum design requirements), and to confirm the minimum design requirements for the mission.

Reference: ESA-ECHO-RP-0001, Issue 1.

EChO, an Exoplanet Characterisation Observatory, is one of five candidate missions for the M3 launch opportunity. A Preliminary Requirements Review (PRR) of all candidate missions has been performed to review their status in support of the M3 selection. This document reports the results of the technical and programmatic review for the EChO mission candidate.

Reference: ESA/SRE(2013)2

This is the Assessment Study Report (also known as the Yellow Book) for EChO - a candidate mission for the M3 launch opportunity in Cosmic Vision.

Reference: SRE-PA/2011.037

This document provides the top-level science requirements for the Exoplanet Characterisation Observatory (EChO), a dedicated mission to investigate exoplanetary atmospheres. The EChO mission was proposed to ESA in response to the M3 call in ESA's Cosmic Vision programme, and was selected for assessment in February 2011. The mission in turn builds on a concept for an Exoplanet Spectroscopy Mission (ESM) that was recommended by the Exoplanetary RoadMap Advisory Team (EPRAT) in 2009/10 for study by ESA. The science requirements were initially derived from the science objectives described in the EChO M3 proposal and have been refined and updated following discussions between the EChO science team and the ESA internal study team. This document was first written as input to the CDF study starting in June 2011. It has been updated continuously since, and will continue to be refined over the course of the study. The aim of this document is to detail the science requirements for all aspects of the mission. As such, the document provides a means by which to understand, trace and support a detailed analysis of the relationship between the science objectives of the mission and the specification of the mission and payload.

Reference: SRE-PA/2011.038/

EChO (Exoplanet Characterisation Observatory) is an M-class mission candidate for the M3 slot within the Cosmic Vision programme, for a planned launch between 2022 and 2024. EChO, with 3 other science missions, was recommended by the Space Science Advisory Committee (SSAC) to enter an assessment study (Phase 0), starting by an ESA internal study followed by parallel industrial study activities.

Within the M3 boundary conditions, the readiness for launch by 2022/2024 is a severe requirement which in practice requires designing the space segment without major technology developments and with minimum developments risks. Therefore, only technologies with estimated Technology Readiness Levels (TRL) of at least 5 by the end of the Phase A/B1 (estimated at the end of 2015) may be used.

This document aims at providing a complete and comprehensive list of all high level mission requirements (including spacecraft and payload, launcher, ground segment and operations) necessary to achieve the science goals detailed in [EChO SciRD (Science Requirements Document), SRE-PA/2011.037/]. It is hence an applicable document that all mission design activities shall comply with. The MRD will be further reviewed matching the results of future study phases (e.g. definition phase) to finally evolve in the System Requirements Document at the start of the implementation phase.

Reference: SRE-PA/2011.039/

This document aims at providing the description of the EChO reference payload complement. The payload complement comprises the following elements:

• The telescope
• The common optics, common in the sense that all alternative instrument designs must use this same set of fore-optics
• The instruments:
  • The science instrument, defined as a spectrometer covering the complete wavelength range required in [EChO MRD (Mission Requirements Document), SRE-PA/2011.038/]. This wavelength range is split into different science channels.
  • The Fine Guidance Sensor (FGS, acting as a non-scientific instrument), also required in [EChO MRD (Mission Requirements Document), SRE-PA/2011.038/] to answer the pointing needs of the spacecraft.

It is also important to highlight that not all elements of this payload complement are applicable to all partners: specificities are foreseen with each partner, i.e. industry and instrument team(s) will have different responsibilities.

Summary of the study performed at ESA's Concurrent Design Facility (CDF), with the goals to:

1. Assess the technical feasibility of the ECHO mission proposal
2. Design an example mission compatible with achieving the science goals

EChO is the Exoplanet Characterisation Observatory. The EChO mission proposal was submitted in 2010 to ESA in response to the Call for medium-size (M-class) missions in the Cosmic Vision 2015-2025 plan with a launch opportunity in the period 2020-22. In February 2011 EChO was one of four missions recommended by the ESA advisory structure and selected for an assessment study. The mission proposal can be accessed through the publication link below.