Doc Ref: ARIEL-RAL-PL-DD-001 ARIEL Payload ARIEL Payload Design Issue: 2.0 Consortium Description Date: 15 February 2017 ARIEL Consortium Phase A Payload Study ARIEL Payload Design Description ARIEL-RAL-PL-DD-001 Issue 2.0 Prepared by: Date: Paul Eccleston (RAL Space) Consortium Project Manager Reviewed by: Date: Kevin Middleton (RAL Space) Payload Systems Engineer Approved & Date: Released by: Giovanna Tinetti (UCL) Consortium PI Page i Doc Ref: ARIEL-RAL-PL-DD-001 ARIEL Payload ARIEL Payload Design Issue: 2.0 Consortium Description Date: 15 February 2017 DOCUMENT CHANGE DETAILS Issue Date Page Description Of Change Comment 0.1 09/05/16 All New document draft created. Document structure and headings defined to request input from consortium. 0.2 24/05/16 All Added input information from consortium as received. 0.3 27/05/16 All Added further input received up to this date from consortium, addition of general architecture and background section in part 4. 0.4 30/05/16 All Further iteration of inputs from consortium and addition of section 3 on science case and driving requirements. 0.5 31/05/16 All Completed all additional sections except 1 (Exec Summary) and 8 (Active Cooler), further updates and iterations from consortium including updated science section. Added new mass budget and data rate tables. 0.6 01/06/16 All Updates from consortium review of final document and addition of section 8 on active cooler (except input on turbo-brayton alternative). Updated mass and power budget table entries for cooler based on latest modelling. 0.7 02/06/16 All Updated figure and table numbering following check. Added comments from KM & GT. Added section 8.4 on other cooler options. 1.0 02/06/16 All Added Executive summary. Prepared for release for MCR datapack. 1.1 23/12/16 All Draft issue to consortium with section authors identified 1.2 10/02/17 All Updated throughout with consortium input for updated designs ready for the MSR submission. 1.3 11/02/17 All Further updates for MSR based on consortium input 1.4 13/02/17 All Added sections on Mechanical, Thermal, detector readout modes, science overview & telescope assy from consortium authors. 1.5 14/02/17 All Added inputs on ACS and AIRS from consortium. Other minor editorial changes. 1.6 15/02/17 All Added comments from EP & KM reviews. Added section on TA thermo-elastic analysis. 1.7 15/02/17 All Final review comments incorporated 2.0 15/02/17 All Document released for MSR datapack Page ii Doc Ref: ARIEL-RAL-PL-DD-001 ARIEL Payload ARIEL Payload Design Issue: 2.0 Consortium Description Date: 15 February 2017 DISTRIBUTION LIST ARIEL Payload Consortium External Co-PIs Study Engineering Team European Space Working Group Leads Agency Giovanna Tinetti Paul Eccleston Goren Pilbratt Giusi Micela Kevin Middleton Ludovic Puig Jean-Philippe Beaulieu Emanule Pace Astrid Heske Paul Hartogh Gianluca Morgante Enzo Pascale Tom Hunt Ignasi Ribas Vania Da Deppo Hans Ulrik Nørgaard-Nielsen Pino Malaguti Michiel Min Jerome Amiaux Mirek Rataj Pep Colome Bart Vandenbussche Jean-Louis Auguères Manuel Gudel Etienne Renotte David Luz Martin Frericks Other Engineering Team As necessary for doc Page iii Doc Ref: ARIEL-RAL-PL-DD-001 ARIEL Payload ARIEL Payload Design Issue: 2.0 Consortium Description Date: 15 February 2017 TABLE OF CONTENTS Document Change Details ......................................................................................................... ii Distribution List ........................................................................................................................ iii Table of Contents .................................................................................................................... iv 1 Executive Summary ....................................................................................................... 11 2 Introduction ................................................................................................................... 12 2.1 Purpose ............................................................................................................................... 12 2.2 Scope .................................................................................................................................. 12 2.3 Applicable Documents ........................................................................................................... 12 2.4 Reference Documents ........................................................................................................... 12 3 ARIEL Science Background ........................................................................................... 15 3.1 The ARIEL Science ............................................................................................................... 15 3.1.1 Background ...................................................................................................................................... 15 3.1.2 ARIEL Science Goals ........................................................................................................................ 15 3.1.3 Observational Strategy ...................................................................................................................... 16 3.2 ARIEL science requirements .................................................................................................. 17 3.2.1 Wavelength coverage & spectral resolving power ............................................................................... 17 3.2.2 ARIEL performances requirements .................................................................................................... 19 3.2.3 ARIEL core sample, observational strategy & sky visibility ................................................................... 20 4 Payload System Design and Architecture ........................................................................ 23 4.1 Payload Architecture & Responsibilities ................................................................................... 23 4.2 The Need for Mechanisms in PLM .......................................................................................... 24 4.3 Design Philosophy ................................................................................................................ 24 4.3.1 Modularity ........................................................................................................................................ 24 4.3.2 Material Selection ............................................................................................................................. 24 4.4 Performance Analysis and Noise Budget ................................................................................. 25 4.4.1 Photometric Stability ......................................................................................................................... 26 4.4.1.1 Frequency Bands of Interest ...................................................................................................... 26 4.4.1.2 Pointing stability ........................................................................................................................ 27 4.4.1.3 Slit Losses ................................................................................................................................ 29 4.4.1.4 Detector stability ........................................................................................................................ 29 4.4.1.5 Thermal stability ....................................................................................................................... 30 4.4.2 Noise Budget .................................................................................................................................... 31 4.4.2.1 Contribution from star variability ................................................................................................. 32 4.4.3 Compliance with requirements ........................................................................................................... 33 4.5 Detector Readout Modes ....................................................................................................... 35 4.5.1 FGS Detectors and Readout Rates .................................................................................................... 35 Page iv Doc Ref: ARIEL-RAL-PL-DD-001 ARIEL Payload ARIEL Payload Design Issue: 2.0 Consortium Description Date: 15 February 2017 4.5.2 AIRS Detectors and readout rates ...................................................................................................... 36 4.5.3 SIDECAR ASIC as controller electronics ............................................................................................ 36 5 System Optical Design ................................................................................................... 37 5.1 Optical System Design Overview ............................................................................................ 37 5.2 Module Optical Division ......................................................................................................... 41 5.3 Common Optics Design ......................................................................................................... 41 5.3.1 Dichroics .......................................................................................................................................... 41 5.3.2 Spectrometer Input Optics ................................................................................................................