ESA UNCLASSIFIED – For Internal Use

PLATO Preliminary Requirements Review Technical Report

Prepared by Review Team Reference SRE-F/2013.075/ Issue 1 Revision 1 Date of Issue 16/12/2013 Status Issued Document Type Distribution

ESA UNCLASSIFIED – For Internal Use

Title Issue 1 Revision 0 Author PLATO PRR Panel Date 16/12/2013 Approved by: Alberto Gianolio Date 17/12/2013

Reason for change Issue Revision Date

Issue 1 Revision 0 Reason for change Date Pages Paragraph(s)

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Table of contents:

1 Introduction ...... 4 1.1 M3 mission in ESA plan ...... 4 1.2 M3 Reviews: Process and Objectives ...... 5 2 Applicable and Reference documents ...... 7 3 List of Acronyms ...... 7 4 OutCOME of the PLATO Preliminary Requirements Review held in 2011 ...... 8 5 New Consortium organization ...... 8 6 PLATO schedule vs M3 reference schedule ...... 10 6.1 Overall PLATO organization...... 10 6.2 CCDs development and delivery ...... 10 6.3 Payload Instrument delivery ...... 10 6.4 ESA estimate of PLATO schedule ...... 11 7 Conclusion ...... 12

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1 INTRODUCTION 1.1 M3 mission in ESA Cosmic Vision plan Following the Call for M3 mission proposals that was issued in July 2010, five mission candidates are today competing for M3 nominal launch slot in 2024: - EChO, an Characterisation Observatory, - LOFT, a Large Observatory For X-ray Timing, - MarcoPolo-R, a Near-Earth Asteroid (NEA) sample return mission, - PLATO, an Exoplanet mission devoted to PLAnetary and Oscillations of stars, - STE-QUEST, a Space-Time Explorer and Quantum Equivalence Principle Space Test. M3 timeline is recalled in Table 1. With the exception of PLATO, for which an assessment study was completed in 2011, the other missions have recently completed their Assessment Phase (phase A). A Preliminary Requirements Review (PRR) of all candidate missions has been performed to review their status in support of the M3 selection.

Event Date Selection of M3 mission candidates Feb 2011 Industrial studies kick-off Feb 2012 Industrial studies mid-term reviews with model payload Jul 2012 Instrumentation AO Sept 2012 Selection of instrument teams Feb 2013 Industrial Phase A studies data package delivery for PRR Sept 2013 ESA technical and programmatic reviews completed Dec 2013 Public presentations, Science Advisory Structure assessment and SSAC Jan 2014 recommendation for M3 selection M3 mission selection by the SPC Feb 2014 Phase B1 completion for the selected mission Nov 2015 M3 mission adoption by the SPC Q1 2016 Industrial Phase B2/C/D kick-off Sept-Oct 2016 M3 nominal launch by 2024 (*) Table 1- Timeline for M3 selection and implementation (*) Compatibility of M3 implementation with a launch by 2022 was requested

PLATO, which has successfully completed the Definition Phase (A/B1), was not selected by the SPC for the M1 or the M2 launch slots in the Cosmic Vision 2015-2025 plan. Following

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M3 Call outcome and ESA consultation of the SSAC, the SPC agreed to consider PLATO as a candidate for M3 slot. The PLATO instrument consortium was restructured and the instrument documentation was update accordingly.

1.2 M3 Reviews: Process and Objectives The independent reviews followed a common procedure and have several objectives: 1) Assess the design maturity of the mission at the end of Phase A 2) Evaluate ESA Estimate at Completion (EaC) 3) Provide recommendations for the next phases While objectives 1) and 2) serve the M3 selection process, the third objective is actually applicable only to the mission that would be selected. For each mission candidate, the reviews were chaired by an experienced project manager and supported by a number of senior engineers and technical experts across the Agency, involving typically about 20 people per mission, with a natural dispersion depending on the mission needs and the review Chairman requests. The reviewers are independent of the study team, and the latter was supporting the review process on the request of the Chairman e.g. by providing the historical background and answering questions raised by the reviewers. For practical reasons, the reviews were conducted in parallel for the five missions and the reviewers were distributed in two panels: - A technical and programmatic panel (also called Review Panel), assessing all technical aspects for the mission implementation, including: mission requirements and flow down to engineering level; spacecraft definition and technology readiness; science payload definition and technology readiness; launch aspects and launcher compatibility; ground segment and operations; spacecraft development plan (model philosophy, schedule for the spacecraft and payload elements) and the associated development risks. - A cost panel, in charge of assessing ESA costs (EaC), taking into account the technical and programmatic findings The input documentation is constituted of: - ESA requirement documents (e.g. Science Requirements Document, Mission Requirements Document, Experiment Interface Documents, etc) - The data packages provided by the two industrial contractors - The data package provided by the instrument consortia The Review Panel was specifically tasked with the following activities:

a- Confirmation of the Mission and System requirements: • Adequacy and completeness of ESA Mission Requirements (MRD) • Adequacy, completeness and traceability of spacecraft, payload, ground segment and launcher requirements • Adequacy and completeness of interfaces definition

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b- Confirmation of the mission technical feasibility: • Mission design justification and compliance with applicable requirements • Concept of operations, observing strategy and modes (where applicable), calibration aspects, driving requirements on mission, spacecraft and payload design • Validity and maturity of the spacecraft and payload design concept • Margin philosophy • Adequacy, completeness and credibility of system, spacecraft and payload budgets and margins • Availability of appropriate models and analyses in support to design definition • Identification of critical technologies for the spacecraft and payload, identification of current technological maturity and availability of credible roadmap to achieve TRL 5 before adoption, critical review of ongoing technology development activities

c- Confirmation of the mission programmatic feasibility: • Critical review of the spacecraft and payload development plans • Adequacy and completeness of the proposed development and verification approach • Model philosophy • Realism and completeness of spacecraft and payload development schedule (incl. margins) • Compatibility of payload need and delivery dates • Critical path analysis • Risk assessment and related mitigation plan • Credibility and compatibility of technology maturation roadmap schedule with system schedule

The reviews were implemented through a series of meetings held throughout October and November. Towards the end of the review process, the major findings were presented to a common management board in the science directorate, who further challenged some findings and, in some cases, requested additional clarifications. A substantial effort was devoted to the harmonisation and cross-verification of the cost estimates. For the specific case of PLATO, since this mission already went through a Preliminary Requirement Review (PRR) in the frame of the M1/M2 selection process and since its technical definition has not changed, the PLATO M3 PRR process was limited to a review of its updated programmatic and cost data package including updated input from the PLATO Consortium, from ESA and from Industries. This document contains the findings of the panel following the review of the programmatic documentation recently updated by the PLATO Consortium, the two industrial study teams for the spacecraft, and by E2V for the PLATO detectors. The report is made public for the sake of transparency and for providing feedback to all teams who actively contributed to the mission assessment phase, namely: the study science team and the science community

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supporting the mission, the science instrument consortia, the industrial study teams, and ESA study team.

2 APPLICABLE AND REFERENCE DOCUMENTS

The present document is a summary of the output of the PLATO Preliminary Requirement Reviews held in 2011 and updated for cost and programmatic aspects in 2013 taking into account the constraints imposed by the M3 mission reference schedule. It is based on the following documents (and references therein):

[RD1]: PLATO Preliminary Requirement Review – Board Report – 05/07/2011

[RD2]: Selection of the M1/M2 missions - ESA/SPC(2011)39 – 19/09/2011

[AD01]: PLATO M3 candidate Mission - Preliminary Requirement Review – Programmatic and Cost Panel Report – Issue 1 – 01/11/ 2013

[AD02]: M3 missions reference schedule - SRE-F/2013.039/ - Issue 1 – Rev. 0 – 23/04/2013

3 LIST OF ACRONYMS

AEU: Ancillary Electronics Unit CCD: Charge Couple Device CDR: Critical Design Review CFE: customer furnished equipment DPU: Data Processing Unit FPA: Focal Plane Assembly ICU: Instrument Control Unit FM: Flight Model FEE: Front End Electronics MRD: Mission Requirement Document PICD-B: Payload Interface Control Document part B PDR: Preliminary Design Review PRR: Preliminary Requirement Review (PRR) ROM: Rough Order of Magnitude TOU: Telescope Optical Unit

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4 OUTCOME OF THE PLATO PRELIMINARY REQUIREMENTS REVIEW HELD IN 2011

The board report of the PLATO Preliminary Requirements Review held in 2011 (see RD1 – section 5) in preparation for the M1/M2 selection process had confirmed the technical feasibility of the PLATO mission space segment. The status of the mission requirements document was considered fully acceptable by the Board. The designs of both Astrium and TAS were judged well defined and already at a pretty mature level. The report further states that the payload interface and performance requirements specified in the mission requirement document (MRD) and the payload interface control document part B (PICD-B) were generally satisfied by the design. For the spacecraft development no new technology was needed to support this mission and the necessary equipment was existing and/or was a modification of equipment from other missions. For the payload development, the 2011 board report indicated that critical aspects existed (e.g. the CCDs, the telescope focusing via thermal control, the complexity of the overall data processing architecture) and had been adequately addressed, i.e. all was in reach of the available technology and the areas requiring development attention had been identified. These conclusions of the 2011 PRR have not been challenged and are still considered valid since the technical definition of the PLATO mission has not changed. However, the board report of the PLATO PRR held in 2011 also concluded (within the frame of the M1/M2 constraints) that the schedule was challenging and clearly depending on some critical developments (e.g. the CCDs) and the timely start of the industrial development activities of the instruments suppliers. These schedule aspects have been reviewed in the PLATO PRR held in 2013 within the frame of the new M3 mission reference schedule. The review takes into account: the payload consortium new organization, the experience for the CCD development and the outcome of a technology development phase of the PLATO CCDs that was conducted by E2V between 2010 and 2013.

5 NEW CONSORTIUM ORGANIZATION

The PLATO Management Consortium (PMC) is organised in three main elements: • Payload: the payload development • Data Center: the PMC contribution to the Science Ground Segment • Science Preparation Management: provides science specifications for the PDC development and organises the international scientific community

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The structure of the PMC presented for M1/M2 has been preserved for the M3 opportunity. Several responsibilities within the PLATO consortium have been reassigned. Most importantly, Heike Rauer (DLR Institute of Planetary Research, DLR-PF, Berlin, Germany) has taken over as PMC Lead from Claude Catala (LESIA, Observatoire de Paris, France) and a new German management team has been put in place. The responsibilities for Payload, Camera and DPS Management have been assigned to German partners.

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6 PLATO SCHEDULE VS M3 REFERENCE SCHEDULE

6.1 Overall PLATO organization The development of the PLATO space segment includes the delivery by ESA of 156 CCDs to the PLATO Consortium and the delivery of 34 cameras by the Consortium to ESA, who will then provide them to the Industrial prime as customer furnished equipment (CFE). Due to this unusually large series of components and subsystems for a space mission, it is felt that extreme care and adequate margins have to be considered to avoid the propagation by domino effect of some delay on CCDs or cameras delivery and a significant escalation of the cost at system level.

6.2 CCDs development and delivery A development Phase of the PLATO CCDs was initiated in 2010 and completed by E2V in November 2013. E2V manufactured and characterized 15 PLATO CCD devices. Following this development Phase, E2V provided a non-binding schedule and a Rough Order of Magnitude (ROM) estimate of the cost of development, qualification and delivery of the required number of flight models of the CCDs. This programme has been divided into two parts, the first for validation/qualification activities and the second for the production of the flight model CCDs. The PLATO validation phase (starting in July 2014) is ending in Febryary 2017, i.e after the anticipated date for mission adoption. The PLATO production phase is starting in February 2017 and reults in staggered delivery of the N-CCDs between May 2018 and March 2019. The resulting delivery dates for the PLATO FM CCDs are well ahead the need dates of the PLATO Consortium for integration into the PLATO FM cameras (between June 2019 and July 2021) assuming a kick-off of the implementation Phase in line with the M3 schedule. This 13 to 28-months margin on CCDs delivery by E2V with respect to the Consortium need date is considered adequate.

6.3 Payload Instrument delivery The PLATO payload includes 34 cameras, each consisting of a telescope optical unit (TOU) with 6 lenses, a plane assembly (FPA) with 4 CCDs and a front end electronics unit (FEE). The development of the 34 Cameras (32 Normal Cameras + 2 Fast Cameras) will be led by a German industry operating under contract by the Consortium. The development approach includes the development of design representative prototypes of the TOU, FPA, FEE, Ancillary Electronics Unit (AEU) as well as breadboards of the Data Processing Unit (DPU) and Instrument Control Unit (ICU) during the Phase B2 to be ready for a Preliminary Design Review (PDR) foreseen in April 2017.

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These important activities are on the overall critical path and their schedule is considered tight. The procurement of the TOU lenses and the TOU integration are also critical since the assembly, integration, and verification of each of the 34 cameras consist of a large number of steps. The PLATO design and development plan assumes a delivery of the first batch of 8 cameras in December 2020, i.e. 16 months after the kick-off of Phase D in August 2018 pending a successful Critical Design Review (CDR).

6.4 ESA estimate of PLATO schedule The development of the PLATO space segment includes the delivery by ESA of 156 CCDs to the PLATO Consortium and the delivery by the Consortium through ESA of 34 cameras to the Industrial prime as customer furnished equipment. The existing margin on CCDs delivery by E2V with respect to the Consortium need date is considered adequate. It is felt that an additional 3 months margin should be taken on top of the 3 months assumed by Industry between camera delivery and integration, thus bringing the delivery of the first batch of cameras to March 2021. The panel considers that these three months can be absorbed in the system schedule by readjusting the system AIT activities, without impacting the launch date. The review panel considers a duration of 18, 24, 38 and 2 months appropriate for respectively the Phase B2, C, D and E1 (until launch only) of the spacecraft development. A combination of the above data leads to a launch date of the PLATO mission in July 2023. Adding the 6-month contingency between FAR and Launch brings the launch date to January 2024, as indicated in the schedule below.

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7 CONCLUSION

Based on the updated programmatic and cost data package provided for the PLATO Preliminary Requirement Review, the review panel concludes that the PLATO mission is feasible with an earliest launch date in December 2023, including the nominal six months margin. The risk on the schedule is considered adequately covered by margin. The scenario with a launch date in 2022 has been analyzed but is not considered feasible.

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