SO-PL-ESA-SYS-5505 Issue: 1.3 Date: 20/10/2009 Page: 1 / 195 SMOS. In-Orbit Commissioning Phase Plan. ESTEC Noordwijk The Netherlands

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1 Page: 1 / 195 SMOS In-Orbit Commissioning Phase Plan ESTEC Noordwijk The Netherlands

2 Page: 2 / 195 DOCUMENT SIGNATURE PAGE Name & Function Date Signature Prepared by: Checked by: Approved by: Approved by: M. Brown SMOS Calibration & Processing Engineer M. Martin-Neira SMOS Principal Instrument Engineer H. Barré SMOS Mission & System Manager A. Hahne SMOS Project Manager

3 Page: 3 / 195 DISTRIBUTION ESTEC/EOP: ESTEC/TEC: INDUSTRY: A. Hahne 1 H. Barré 1 M. Suess 1 EADS-CASA: M. Brown 1 ESRIN: J. Closa Soteras 1 S. Cooke 1 S. Delwart 1 S. Mecklenburg 1 UPC: B. Duesmann 1 N. Wright 1 M. Zundo 1 I. Corbella 1 CNES: F. Torres 1 K. McMullan 1 S. Ekholm 1 M. Venet 1 Deimos: J. Marti M. Martin-Neira 1 CESBIO: J. Barbosa 1 W. Rits Y. Kerr 1 HUT/TKK: F. Cabot 1 J. Kainulainen 1 Documentation 1

4 Page: 4 / 195 DOCUMENT CHANGE RECORD Iss./Rev. Date Page Observations Draft 01 15/12/06 All First issue of document. Generated for M-CDT-KP review, February Draft 02 29/06/07 All Second issue of document incorporating detailed elaboration by MB & SMOS project team. Draft 03 16/07/07 All Third issue of document incorporating detailed comments/inputs from internal project review by AH, HB, NW, SD (all ESA) & JC (CASA). Draft 04 15/02/08 All Fourth issue of document incorporating comments following GS-CDR and internal discussions with ESRIN. Additional inputs from AH, MMN, SD and NW (all ESA) /05/08 All First official release of document to SMOS project. Additional inputs from project teams at ESTEC and ESRIN plus CASA (JC), SAG and some L2 users /08/08 All Minor additions to instrument-led activities by UPC. 1.2 Draft 08/05/09 Sidebars Major changes following working meetings at ESTEC, ESAC and CNES on Instrument-led Activities during the Commissioning Phase /09/09 Sidebars Major changes to draft version following review by the IOCP team /10/09 Sidebars Minor changes

5 Page: 5 / 195 TABLE OF CONTENTS 1 INTRODUCTION DOCUMENTS Applicable Documents Reference Documents THE SMOS MISSION Mission Objectives Mission Components Mission Phases Commissioning Phase Launch Date IOCP Objectives COMMISSIONING PHASE DECOMPOSITION LEOP Platform Check-out Payload Check-out Phasing of Payload Switch-on X-Band Switch-on X-band Data Acquisition Failure Scenario SODAP Schedule Instrument Characterisation, Calibration & Verification Instrument Thermal Stability (Characterisation) Correlator Functionality (Characterisation) Instrument Electrical Stability (Characterisation & Calibration) First Deep Sky View (Calibration) First Galaxy L1b Image (Verification) First Calibrated Dual Polarisation L1c Image (Characterisation) First Full Polarisation Mode External Calibration (Calibration) First Calibrated Full Polarisation Image (Characterisation) Payload Commanding (Verification) Payload Thermal Tuning (Characterisation) Instrument Measurement Modes (Characterisation) Instrument Calibration Modes (Calibration) RF Interference (Characterisation) Reduced Attitude Control (Characterisation) Impact Of Solar Array Orientation (Characterisation) NIR Temperature Sensitivity (Characterisation)...66

6 Page: 6 / Receiver Noise Temperature Monitoring (Verification) Data Downlink Optimisation (Characterisation) Sun Self-estimation (Characterisation) Loss Of GPS Signal (Characterisation) Impact Of Leakage on Baselines (Characterisation) All LICEF Instrument (Characterisation) NIR PMS Calibration (Earth Targets) Temperature Characterisation External Target Verification Validation Of 3 rd & 4 th Stokes Parameters Using NIRs Instrument Validation In-Orbit CAS Validation (PMS Cold Sky Validation) PMS Offset & PMS Attenuator Validation LICEF Receiver Temperature Validation Moon As A Validation Target Galaxy Imaging (Validation) U-Noise During LO Calibration Product Calibration (L1a, L1b) Performance Verification Product Verification L1 Product Verification L2 Product Verification Product Validation (L2) Vicarious Calibration For Long-term Monitoring Summary Of IOCP Activities General Activities GROUND SEGMENT VALIDATION Transfer of Algorithms from L1PP to L1OP Operations Procedures and Plans Verification Execution Of Ground Segment Training Activities Relationship Between Payload Activities And Ground Segment Activities SCHEDULE Scheduling Principles SMOS TEAM ORGANISATION Commissioning Team Functions Of The IOCP Core Team Operations Of The IOCP Commissioning Team SMOS Validation and Retrieval Team (SVRT)...115

7 Page: 7 / MANAGEMENT OF ANOMALIES AND CHANGES Management of Anomalies The Anomaly Review Board (ARB) Software Maintenance Space Segment Software Ground Segment Software Management of Changes Changes Following Anomalies Evolutionary Changes (Commissioning Phase) Configuration Control Board (CCB) TASKS AND REQUIREMENTS Operation Timelines LEOP Initial Instrument Switch-On Routine Operations During IOCP Orbit Requirements Processing Requirements Archiving Requirements Distribution Requirements Ground Segment Operation Requirements Ground Segment Configuration Requirements REPORTING Project Reporting Reporting to External Bodies (TBC) REVIEWS RESOURCES Tools and Infrastructure ESA Project Staff Space Segment Industrial Support Ground Segment Industrial Support ABBREVIATIONS Appendix A MIRAS-led Activities Appendix B Ground Segment Activities Appendix C System Requirements Verification Matrix Appendix D Project Schedule...180

8 Page: 8 / 195 Appendix E External Calibration Opportunities in Appendix F Terms Of Reference Of IOCP Functions...187

9 Page: 9 / INTRODUCTION The SMOS In-Orbit Commissioning Phase (IOCP) will start immediately after the Launch and Early Orbit Phase (LEOP) and finish when the complete SMOS System (Space and Ground Segment) has been commissioned. The IOCP is concluded by the In-Orbit Commissioning Review (IOCR), at which the mission will be declared ready for the nominal operational phase [AD01]. This milestone marks the handover of responsibility for the mission from the SMOS Project Manager to the SMOS Mission Manager. The IOCP is the most demanding phase of the entire mission for both the space and ground segments. The responsibility for the IOCP is delegated to the SMOS Commissioning Phase Manager. The allocated duration for the IOCP is 5.5 months, following on from the LEOP which has an allocated duration of 2 weeks. This plan defines the context, the purpose and the main characteristics of the SMOS In-Orbit Commissioning Phase. In particular, it addresses The IOCP objectives Breakdown into its sub-phases and tasks Preparatory activities Organisation and interaction of the team(s) Management of anomalies and requests for changes Reporting and reviews Planned resources The schedule for the execution of the sub-phases and tasks will be defined separately to this plan. This will allow the IOCP timeline to be continually developed, both before launch and during the IOCP itself. Furthermore, it is assumed that the IOCP activities will be begun only after completion of the LEOP. The initial schedule is referenced in an annex to this document. The SMOS mission is introduced in section 3 where the objectives and mission phases are described, with the main emphasis on the IOCP and its context within the overall programme. The SMOS mission operations concept is described in [AD02]. It establishes the operational philosophy for the overall mission. At the highest level the IOCP activities can be split between those based on the instrument and those based on the ground segment elements. The IOCP is split into a number of sub-phases which support the overall objectives. The Commissioning Phase sub-phases are decomposed into activities in sections 4 and 5. These activities, following-on from the orbit acquisition in the LEOP, can be classified into the following categories Payload Switch-On & Data Acquisition Instrument Characterisation, Verification & Validation Data Processing

10 Page: 10 / 195 Product Calibration (up to L1c) Product Verification Performance Verification Product Validation (L2) Ground Segment Verification/Validation The main components of the SMOS instrument and supporting ground segment are addressed in section 3. This provides an introduction to the major aspects which need to be included in the calibration scheme. The phasing of the mission is introduced, with emphasis on the IOCP. Finally, the objectives of the IOCP are presented. The IOCP activities are proposed in sections 4 and 5, with a split between the instrument-based activities and the ground segment activities. The main sub-phases, introduced in section 3, are decomposed into individual tasks. These represent standalone procedures, but have relative constraints between them. Each task has a primary objective, but may also support several secondary objectives. For example, a task may support both the instrument verification and part of the ground segment validation. The sub-activities presented in sections 4 and 5 will be further detailed in the plans from the relevant body (industrial team) doing the analysis. The main message for these teams is to be consistent with this overall plan. This plan should be read at the same time as the High Level Planning which is the first attempt at putting all the tasks into an overall timeline, or schedule as referenced in Appendix D, for the IOCP. Note that the timeline for the SODAP is defined separately.

11 Page: 11 / DOCUMENTS 2.1 Applicable Documents [AD01] SMOS System Requirements Document, SO-RS-ESA-SYS-0555, Issue 4/2, 30/06/05. [AD02] SMOS Mission Operations Concept Document, SO-TN-ESA-GS-1118, Issue 1.3, 06/02/06. [AD03] SMOS-PLM Command and Control, SO-TN-CASA-PLM-0279, Issue 2.5, 12/02/07. [AD04] Ancillary Packet Description, SO-TN-CASA-PLM-0594, Issue 3.1, 13/02/07. [AD05] Operational Interface Agreement Between The Satellite Command-Control Center And The Payload Programming Center, SMOS-OP-0-IF-8003-CNES, Issue PR, Rev 5, 09/02/07. [AD06] SMOS Calibration and Characterisation Plan, SO-PL-ESA-SYS-3771, Issue 1, 31/01/07. [AD07] SMOS Payload Requirements Specification, SO-RS-ESA-PLM-0003, Issue 3.2, 21/07/05. [AD08] SMOS Satellite Specification, SMOS-LB-SP-302-CNES, Issue 3, Rev0, 28/07/04. [AD09] Sequence Plan: SMOS LEOP, SMO-OP-0-SPL-8010-CNES, Edition PR, Rev 3, 09/02/07. [AD10] SMOS Payload Technical Description, SO-TN-CASA-PLM-0017, Issue 05, 30/09/05. [AD11] SMOS PLM Deployment Sequence, SMOS-SO-NT-472-CNES, Edition 1, Rev 0, 06/06/06. [AD12] PLM PROTEUS Flight Operations Procedures, SO-TN-ESA-SYS-2137, Issue 1.1, 05/07/06. [AD13] SMOS Mission Analysis Report, SO-TN-ESA-SYS-1084, Issue 3.1, 09/02/07. [AD14] SMOS PLM PM-18 Electrical Splinter, SO-HO-CASA-PLM-1230, 24/01/07. [AD15] CCU Requirements Specification,

12 Page: 12 / 195 SO-RS-CASA-PLM-0050, Issue 3.4, 01/10/04. [AD16] CMN Requirements Specification, SO-RS-CASA-PLM-0051, Issue 2.2, 09/01/06. [AD17] SMOS Packet Utilisation Standard, SO-TN-SSL-ASW-002, Issue 2.3 Draft, 14/07/06. [AD18] SMOS L1 Processor L0 to L1a Data Processing Model, SO-DS-DME-L1PP-0007, Issue 2.2, 09/04/07. [AD19] Calibration Requirements, Constraints and Strategy, SO-TN-CASA-PLM-0839, Issue 3.2, 27/04/07. [AD20] Image Validation Test Plan, SO-PR-CASA-PLM-1041, Issue 1.5, 03/03/07. [AD21] NIR Calibration and Characterisation Plan, SO-TS-HUT-NIR-0005, Issue 05E, 29/11/06. [AD22] NIR Requirements Specification, SO-RS-CASA-PLM-0049, Issue 3.1, 21/04/05. [AD23] NIR-1 Test Report (FM), SO-TR-HUT-NIR-0061, Issue 1B, 31/08/06. [AD24] NIR-2 Test Report (FM), SO-TR-HUT-NIR-0062, Issue 1B, 31/08/06. [AD25] NIR-3 Test Report (PFM), SO-TR-HUT-NIR-0063, Issue 1B, 31/08/06. [AD26] SMOS L1 Processor L1a to L1b Data Processing Model, SO-DS-DME-L1PP-0008, Issue 2.2, 09/04/07. [AD27] Antenna Test Campaign Requirements Specifications, SO-RS-CASA-PLM-0148, Issue 3.0, 27/09/05. [AD28] Usage Of Calibration Data In Measurement Processing, SO-TN-CASA-PLM-1075, Issue 2.0, 20/04/07. [AD29] Generation of a Sky Map to be used in Lvl1 and Lvl2 Processors, N. Floury (ESA), Issue 1.0, 21/04/06. [AD30] Definition of Coordinate System/Reference Frame and Units Nomenclature, SO-PL-CASA-PLM-0022, Issue 2.2, 14/09/06. [AD31] SMOS In-orbit Calibration Plan. Phase C-D,

13 Page: 13 / 195 SO-TN-UPC-PLM-0019, Issue 1.5, 17/01/07. [AD32] LICEF Requirements Specification, SO-RS-CASA-PLM-0048, Issue 4.0, 02/12/04. [AD33] In-orbit CAS and LICEF Receiver Temperature Validation, SO-TN-UPC-PLM-0054, Issue 2.1, 24/10/06. [AD34] LICEF Calibration and Characterization Files Requirements, SO-RS-CASA-PLM-0728, Issue 1.0, 14/09/05. [AD35] SMOS ESA/CNES Coordination Meeting, PLM Switch On, ESTEC, 15/05/07. [AD36] UPC IVT Meeting, SO-MN-UPC-PLM-0019, 03/07/07. [AD37] SMOS PLM Flight Operations Plan, SO-TN-ESA-SYS-4703, Issue 1.1, 27/11/06. [AD38] PLM: Integrated System Tests (IST) Definition, SO-PR-CASA-PLM-1040, Issue 1, 16/02/07. [AD39] NIR In-Orbit Characterisation Over Temperature, SO-TN-HUT-NIR-0103, Issue 00A (Draft), 17/06/07. [AD40] Payload Operations Manual, SO-UM-CASA-PLM-0700, Issue 3, 19/01/07. [AD41] Alcatel Inputs for the SMOS PDIS (Payload Design and Interface Specification), SMOS-ASP-SP-0004, Issue 4, 30/09/05. [AD42] SMOS L1 Product Format specification, SO-IS-DME-L1PP-0002, Issue 2.1, 09/04/07. [AD43] SMOS L1 Processor L1c Data Processing Model, SO-DS-DME-L1PP-0009, Issue 2.0, 17/11/06. [AD44] SMOS Hand-over Plan, SO-PL-ESA-SYS-5917, Issue 1, 10/05/07. [AD45] SMOS Validation and Retrieval Plan, SO-PL-ESA-SY-3898, Issue 1.0, 01/07/07. [AD46] IOCP High Level Plan 15 October 2009, ESA presentation attached to this document.

14 Page: 14 / 195 [AD47] SMOS In-Orbit Commissioning Preparation Meeting, SMOS-0-CR-1006-CNES, 07/04/09. [AD48] SMOS DPGS Pre-Launch Rehearsals And Commissioning Support SOW, XSMS-GSEG-EOPG-SW , Issue 0,1, 05/11/08. [AD49] SMOS System and PROTEUS Bus In-Flight Assessment Test Plan, SMOS-0-TP-1003-CNES, Issue 1, 10/04/09. [AD50] RF-SODAP Activity zip (containing RF Task During SODAP issue 1.5 (pdf) and X-Band_passes synoptic v8 (xls)) 2.2 Reference Documents [RD01] The Flat Target Transformation, M. Martin-Neira, et al, IEEE Trans. On Geoscience and Remote Sensing, Special Issue on SMOS, Vol. 46, No. 3, March [RD02] The Visibility Function in Interferometric Aperture Synthesis Radiometry, I. Corbella et al, IEEE Trans. On Geoscience & Remote Sensing, Vol. 42, No. 8, August [RD03] Comparison of Model Prediction With Measurements of Galactic Background Noise at L-Band, David M. Le Vine, IEEE Trans. Geoscience & Remote Sensing, Vol. 43, No. 9, September [RD04] Sun Effects in 2-D Aperture Synthesis Radiometry Imaging and Their Cancellation, A. Camps et al, IEEE Trans. On Geoscience and Remote Sensing, Vol. 42, No. 6, June [RD05] Assessment of the Impact of the SMOS Satellite Structure and Solar Panels on the LICEF Antenna Pattern and the Effects on Sun Suppression, TICRA, S , September [RD06] Implementation design for SMOS Vicarious calibration monitoring algorithms v1, R. Crapolicchio and P. Ferrazzoli. [RD07] Operational vicarious calibration monitoring for SMOS, M. Meloni, Tor Vergata, March 2008.

15 Page: 15 / THE SMOS MISSION This section presents an overview of the relevant aspects of the SMOS mission, in particular the mission phases and the context of the IOCP within the overall programme. 3.1 Mission Objectives The SMOS mission has been defined to provide global maps of soil moisture (SM) and ocean salinity (OS) with the specified quality (accuracy, sensitivity, spatial resolution, spatial and temporal coverage) ([AD01]). Improved assessments of both SM and sea surface salinity (SSS) will allow significant progress to be made in weather forecasting, climate modelling and extreme events modelling. 3.2 Mission Components SMOS is the second mission to be selected as an Earth Explorer Opportunity Mission within the Living Planet Programme (the first being CryoSat). The major components of the SMOS system are shown in Figure 3.1 The following elements of the SMOS mission are relevant to the IOCP activities. The SMOS satellite comprises a single payload module (PLM) or instrument, known as MIRAS (Microwave Imaging Radiometer by Aperture Synthesis), developed by ESA/CASA, coupled to a PROTEUS platform developed by CNES/Alcatel. MIRAS synthesises a large aperture from a reasonably sized 2-D array of passive microwave radiometers. By using interferometric techniques the required coverage and spatial resolution ([AD01]) can be achieved without the need for a large antenna. The SMOS Satellite Operations Ground Segment (SOGS) is responsible for operating, controlling and monitoring the satellite. The SOGS comprises the Command and Control Centre (CCC), the Telemetry, Tracking and telecommand Earth Terminal (TTCET) and the associated Data Communications Network (DCN). The CCC is based on the generic PROTEUS control centre and is located in Toulouse, France. The TTCET is an S-band ground station, located in Kiruna, Sweden, providing bidirectional communication. Additionally, a second station at Aussaguel, France, may also be used. The choice of station(s) should be transparent to the payload operations. The PayLoad operations Programming Centre (PLPC) is in charge of programming, controlling and monitoring the SMOS payload, namely the MIRAS instrument. The PLPC acquires and monitors all SMOS PLM housekeeping telemetry received by the S-band link of the SOGS. The Data Processing Ground Segment (DPGS) controls the acquisition, processing, archiving and dissemination of the scientific and auxiliary data produced by MIRAS. The DPGS comprises the X-Band Acquisition Station (XBAS), the Payload Data

16 Page: 16 / 195 Processing Centre (PDPC), the SMOS Plan Generation Function (SPGF), the User Service and, finally, the associated Data Communications Network (DCN). The XBAS, PDPC and SPGF are located at ESAC in Villafranca, Spain, whilst the User Service is provided by both ESAC and ESRIN, Italy. Figure 3.1: SMOS System Architecture (reproduced from [AD01]) The location of ESAC for the XBAS restricts the number of passes available for data downlink to 4 per day, two ascending passes and two descending passes. The data will then be up to 10 hours old (best case) when acquired on-ground ([AD01]). Consequently, the XBAS will now be complemented by additional ground station(s) to form the Near Real-Time system (not shown in Figure 3.1). Instead of downlinking data on 2 or 4 orbits per day to the XBAS, the data will be downlinked on every orbit. If the XBAS is visible, it will receive the data; otherwise the additional ground station(s) will be used and the data transferred to the DPGS at ESAC. The SPGF defines and generates the high-level Payload Operations Plan (POP) in the form of pre-scheduled timelines. These are passed to the PLPC, which then interfaces to the SOGS.

17 Page: 17 / 195 The PDPC comprises the Science Data Processing Centre (SDPC) and the Calibration and Expertise Centre (CEC). The SDPC, known as the Fast Processing Centre, processes, calibrates and archives the scientific data up to level 2 inclusive. The operational processing chain includes the Systematic Product Quality Control (SPQC) which will provide the quality stamp for the operational products. The CEC will include software analysis tools such as the Monitoring Facility (MF), the Interactive Analysis Toolbox (IAT) as well as a copy of the prototype processor (L1PP). The NRT acquisition system, located at Svalbard, will also acquire the X-band telemetry which contains both the science data (CORR-TM) ([AD03]) and the ancillary data (I-HKTM) ([AD04]). This latter data stream provides all the additional data produced on-board (e.g. instrument data such as instrument mode, PMS values, temperatures, etc. or satellite data such as attitude, etc) which is necessary for the ground processing. The ancillary data is also provided in the S-band telemetry stream. The User Service will not be active during the IOCP beyond preparation activities. The Long Term Archive (LTA) will store all data products (L0, L1 & L2). The Reprocessing Centre, co-located with and interacting with the LTA, performs the distribution of products to internal (e.g. instrument team and Cal/Val teams) and external users (mainly investigators identified through the AO procedure). The Expert Support Laboratories (ESLs) will support the mission in terms of calibration and processing of level 1 and 2 products. The LABOs and CATDS are concerned with higher level products (levels 3 and 4) and are outside the scope of the IOCP. Furthermore, they will not be active during the IOCP. The use of existing elements within the SMOS system architecture imposes programmatic and operational constraints. In particular, the PROTEUS generic ground segment (GS) and the location of the XBAS at ESAC and NRT acquisition station at Svalbard affect the operational timelines. The PROTEUS GS is used both to uplink the PLM telecommands (TC) and to receive the PLM telemetry (TM), through the S-band link. This leads to the following constraints nominal operations only during CNES working days uplink-and-forget handling of PLM TCs & TM limited uplink availability (4 passes per day) due to it being a generic system, shared by many satellites long nominal planning loop (1 week) TM reception delays between TTCET and PLPC

18 Page: 18 / 195 According to [AD05] the PUS-HKTM (containing CCSDS standard packets) will be available on the PLPC gateway less than 2 hours after the end of the pass. The IOCP activities can be divided into two categories, as follows Instrument-led activities which confirm that the SRD technical requirements are met Ground-segment activities which confirm that the GS is stable and provides a steady stream of the expected data types 3.3 Mission Phases The Launch and Early Orbit Phase (LEOP) begins with the launch countdown. The launch will be on a Rockot-Breeze KM from the Plesetsk Cosmodrome in Russia. The LEOP activities are controlled from the SOGS. After separation from the launcher, the PROTEUS solar panels are deployed and the MIRAS survival heater lines are switched-on. Subsequently, the 3 MIRAS arms are deployed. The phase ends once the satellite has reached operational status, with all deployments completed, attitude and thermal control established and in the final orbit. Next, within the Commissioning Phase the payload is switched-on to characterise, calibrate and verify the functionality of the instrument, data downlink and ground processing. End-to-end testing will be performed on all subsystems of both the space and ground segments. A range of calibration strategies will be examined in order to assess the impact on the products. The frequency of the calibration activities will be determined for the subsequent nominal operations phase. Also, a recommendation on the nominal measurement mode, either Dual or Full polarisation, will be made at the Commissioning Phase Review. The launch campaign (LC), LEOP and IOCP are sometimes grouped together as Phase E1. Subsequently, the exploitation phase, or Phase E2, is performed. For SMOS this is expected to last 2.5 years. During this phase, also known as the Nominal Operations (NO) Phase, the end-to-end system should be operated according to the recommendations from the In-Orbit Commissioning Review. 3.4 Commissioning Phase The context and high level breakdown of the IOCP is shown in Figure The classical Phase C/D comprising the development and test (DT) phases concludes with the Flight Acceptance Review (FAR) which gives the consent to ship to the launch site. Note that preparations for the in-flight commissioning activities may continue up until launch. The time interval between the FAR and the launch date (i.e. the end of the LC) is expected to be at least 2 months, with a longer duration being imposed by external factors (e.g. other launches, or slippage in the proposed launch date). The LC is scheduled to last 38 days.

19 Page: 19 / 195 At the IOCR the in-flight system (platform and payload) and the ground segment (processing chains and data dissemination) should be fully verified and in a stable state such that no further changes for optimisation of the system elements are necessary. However, the on-ground data processing elements may be improved and optimised over the mission lifetime. Preparation DT LC LEOP NO IOCP FAR Phase C/D Launch Phase E1 Figure 3.4.1: Mission Operations Context of IOCP IOCR Phase E2 The IOCP is divided into a number of sub-phases which focus on specific aspects of the overall mission. These sub-phases are inter-dependent and overlap in time, as shown in Figure Within the 5.5 months duration for the IOCP it was initially proposed to plan activities for about 4 months and allow the remaining 1.5 months for contingencies including margins, repeat activities and additional activities. This was superseded by the timing given in the High Level Planning ([AD46]). The platform check-out will be performed by CNES. It is assumed that this will occur immediately after completion of the LEOP. Potentially, some of these activities could be performed during the LEOP. Consequently, these activities run in parallel to the first of the instrument activities. The first in-flight activity for the instrument is the payload switch-on. The payload shall remain off until all the out-of-plane manoeuvres have been completed. This is a constraint imposed by the platform as part of its battery management. However, the instrument can be on during any subsequent in-plane manoeuvres since this is essentially the same as the External Calibration attitude changes for the instrument. Following the meeting at CNES on the 7 th April 2009 it was agreed between ESA and CNES that the instrument switch-on would happen on day 14 of the LEOP ([AD47]). This then allows a few more days for the early instrument tests (checking the functionality). Following the instrument switch-on the payload and ground segment verification will commence. (Strictly, the ground segment verification begins during the switch-on as the X-band downlink is activated.) This should be a systematic check of the instrument functionality and a progressive cycling through the instrument modes (the instrument is immediately in Dual Polarisation imaging mode after switch on). These activities will include the various calibration and instrument validation activities

20 Page: 20 / 195 presented in [AD06]. In general the philosophy for the IOCP is success oriented. That is to say, it is assumed that the instrument will function correctly in its initial switch-on configuration. Consequently, there will not be any verification of the redundant configurations (e.g. use of cross-strapping) unless resulting from an anomaly. The nominal X-band downlink introduces noise into some baselines when stuffing is being transmitted. The preferred solution is to activate the redundant downlink which does not introduce any spurious signals. Consequently, the configuration to be used in the IOCP is known as Prime and consists of all the redundant units. Platform Check-out Payload Switch-On Characterisation, Verification & Validation Data Processing Product Calibration (L0, L1a, L1b, L1c) Performance Verification Product Verification (L1) Product Verification (L2) Product Validation (L2) Long-term Monitoring Ground Segment Verification IOCP Figure 3.4.2: IOCP Sub-Phases The objectives for the IOCP can be broadly categorised into two main topics (see section 3.6), namely Verification of the SRD technical requirements ([AD01]) Establishment of a stable ground segment and operations plan The IOCP activities in the first topic are essentially driven by the instrument. Generally, each activity (e.g. for characterisation, calibration, verification or validation) relates to specific operation of the instrument (and data processing). The supporting

21 Page: 21 / 195 ground segment activities are an essential part of each activity and may include data acquisition on-ground, data distribution within the ground segment, data processing and analysis. However, the ground segment is not considered as the main driver for these instrument activities. For the second topic the ground segment verification is covered by an additional set of activities, but can of course make use of the activities from the first topic. The ground segment verification will ensure that a regular stream of data products is available, whilst the instrument verification will ensure that the scientific data content in the products has the expected quality. The ground segment verification activities can commence as soon as the instrument is switched-on, particularly for the commanding and data acquisition elements. The SDPC utilises the level 1 operational processor (L1OP) whilst the CEC contains the level 1 prototype processor (L1PP). The two processors implement the same algorithms which have been verified during development. The L1OP will begin systematic processing of all data produced by the instrument. In parallel, the L1PP will be used in the CEC during the IOCP to support the analysis of the specific IOCP activities, including the non-nominal operations, using a subset of the data. Additionally, as an offline tool, the L1PP will be used to investigate anomalies and identify software modifications and corrections as needed. Following verification and validation of algorithm modifications within the L1PP, these changes will be implemented in the L1OP. The co-location of both processors (and operators) at ESAC during the early phase of the IOCP will enable this update cycle to be performed efficiently. The payload verification, calibration and validation activities require the ground segment to be able to disseminate level 0 products to the CEC. Nominally, these activities can commence after switch-on and the initial data distribution verification. The product calibration, up to the L1c product, includes assessment of all the lower level products (e.g. L0, L1a and L1b and browse). Each product level should be verified before the higher level products. The (performance) verification of the calibrated level 1b & 1c products can be undertaken once the payload verification and calibration activities have been performed. The long-term monitoring (for instrument stability) can use data from the complete IOCP once the instrument is switched-on. These activities can make use of the CEC as well as the nominal ground segment monitoring facilities within the SDPC such as the SPQC and MF. Strictly, the validation of the level 2 products should not begin until the instrument activities have been concluded and a calibrated level 1c product is available. However, by starting the level 2 product validation earlier, the Users will benefit from exposure to the real products (even if they are not fully calibrated).

22 Page: 22 / 195 Note that these sub-phases will be decomposed into individual activities in the subsequent chapters. Furthermore, the overall timeline will continue to evolve as activities are refined following the on-going ground testing and characterisation activities. Generally speaking, the instrument activities will be led by the ESA SMOS project team at ESTEC, responsible for the instrument procurement. Similarly, the ground segment activities will be led by ESA SMOS project team at ESRIN, responsible for the DPGS procurement (see section 6). 3.5 Launch Date For the purposes of timing within this plan the launch date is taken as Monday 2 nd November 2009 The main impact of a change in launch date is the supporting ground truth experiments. These have to be organised months in advance, and they do not want staff unnecessarily in potentially inhospitable regions. However, this relates more to Cal/Val activities than IOCP activities. This launch date also means that the IOCP activities will have to be suspended over the Christmas/New Year period since the ESAC site is closed. This is included in the high level planning ([AD46]). 3.6 IOCP Objectives The objectives of the IOCP are to bring the (satellite and) instrument into a fully operational condition to optimise the (satellite and) payload in terms of on-board software, parameters and operations in order to best meet the mission requirements to verify that the performance of the (satellite and) payload meets its requirements to verify the mission operations procedures to bring the ground processing segment into a fully operational condition to calibrate the level 1 data products to verify that the level 2 products are credible The compliance of the in-orbit performance to the mission requirements ([AD01]) should be contained in a System Requirements Verification Matrix. The system requirements ([AD01]) have been split between the payload ([AD01) and the platform ([AD08]). The in-orbit performance verification matrix should be a condensed version of the payload requirements, being limited to those requirements which can be verified in-flight. Note that some requirements which can only be verified by analysis before launch will now be verified by testing.

23 Page: 23 / 195 These high-level requirements presented in this section are decomposed into smaller elements in the activities in the next section, which define the team involved in each task, the tools required, the timelines and the interaction with other tasks. The review of the operational readiness of the ground segment for the subsequent nominal operations phase is considered to be a precursor to the IOCR. This is all line with the handover plan [AD44].

24 Page: 24 / COMMISSIONING PHASE DECOMPOSITION The breakdown into sub-phases has been introduced in Figure The key points to be noted are Sub-phases are not necessarily sequential Sub-phases may have both short-term and long-term elements Each sub-phase can be broken down into tasks, with relative constraints between them. The following sub-sections provide a summary of each sub-phase, whilst the tasks themselves are described in appendices A and B. The instrument-based activities within the IOCP are categorised as characterisation, calibration, verification or validation with specific limitations to the instrument or lowerlevel products. For completeness, these categories relate to the following definitions Instrument Characterisation is the measurement of the typical behaviour of instrument properties, including subsystems, which may affect the accuracy or quality of its response or derived data products. For the IOCP these in-flight activities can be compared to the on-ground characterisation performed prior to launch. Product Calibration is the process of quantitatively defining the system response to known, controlled system inputs. These in-flight activities form a major element of the IOCP, from which a reduced set are carried through to the Operational Phase. Performance Verification encompasses the testing and analysis necessary to provide confirmation that all instrument requirements have been met. These activities ensure that the system provides the correct products (in terms of the quality of the performance). Instrument Validation is the process of assessing, by independent means, the quality of the instrument data. In this context the validation is an independent verification. These definitions, although slightly modified, are consistent with those used in other areas of the SMOS programme, in particular for the calibration and characterisation ([AD06]). Additionally, product verification is the process of checking the correctness or integrity of the contents of the file. The instrument-led activities defined in this section are defined by ESTEC, whilst the ground segment activities, given in the next section, are defined by ESRIN. A summary of the IOCP objectives is given in Table 4.1 (the colour-coding of the subphases corresponds to those used in Figure 3.4.2). The long-term monitoring is included as a by-product of the characterisation, verification and validation activities. The nominal long-term monitoring will feed off the products produced by the main operational processing chain. However, it will also be possible to use the functionality

25 Page: 25 / 195 of the monitoring facility in a more hands-on way within the CEC. In this way the input can come from the L1PP instead of the L1OP. Note that the ground segment validation is covered by section 5, although it is included here for completeness. In fact, the ground segment validation encompasses those tasks which specifically support the instrument-led activities, and those which relate to the overall ground segment. The first type is included with the instrument-led activities in this section, while the others are given in section 5. Success Criteria For many of the activities defined in the following sections, success criteria will be defined. The issue of non-compliance is addressed in the definitions of the IOCP activities in appendices A and B. These need to be considered on a case-by case basis since the outcome can vary from use as is through repeat activity through adjust approach to failure.

26 Page: 26 / 195 Sub-phase Objective Start Event End Event Comments LEOP To bring the satellite into a safe Satellite switch-over to Stable orbit CNES responsibility and stable in-orbit configuration internal power pre-launch Platform Check-out To verify and optimise the Starts during LEOP Stable configuration two CNES responsibility performance of the platform weeks into IOCP Payload Switch-On and Data Acquisition To bring payload and the up/down links into an operating condition Platform services ready to support payload Payload fully functional, ready for parameter tuning, up/down links fully operational Instrument Verification & To optimise the payload Payload switched-on Payload parameters and Characterisation parameters and operations operations tuned Data Processing To ensure that the processors Payload switched-on Processors provide all L1 provide the products data products Instrument Validation To support the verification and Payload switched-on Payload parameters and characterisation sub-phase operations tuned Product Verification (L1) To ensure the integrity of products Payload switched-on All L1 data products conform to specifications Product Calibration Initial optimisation of the Level 1c Platform, payload and Commissioning Phase processing parameters and processing parameters Review algorithms (including L0, L1a & properly set. L1b) Performance Verification To determine the performance of Initial product calibration Commissioning Phase the payload (Level 1c) performed Review Long-term Monitoring To support instrument verification Payload switched-on Commissioning Phase and characterisation Review Ground Segment Verification To bring the ground segment into a Availability of X-band Ground segment state where it can support the data (end of LEOP) operations and interfaces mission fully functional Product Validation (L2) Initial optimisation of Level 2 Initial product calibration Initial validation processing parameters and (Level 1c) performed performed for Comm. algorithms Phase Review Table 4.1: IOCP Activities MIRAS in mode(s) which support these activities Includes monitoring long-term No further payload changes expected after this process is completed Included as part of instrument verification

27 Page: 27 / LEOP The Launch and Early Orbit Phase (LEOP) will bring the satellite into a safe and stable in-orbit configuration. It begins prior to launch at the switch-over to satellite internal power. The detailed LEOP planning and implementation is a CNES responsibility with ESA support for the PLM deployment and configuration ([AD09]). This document describes both the overall sequence of events and the detailed sequences with links to the Flight Control Procedures (FCPs). It is assumed that the payload is OFF until the LEOP is completed. The LEOP is not treated as part of the Commissioning Phase. However, since it includes sequences which bring the instrument into a state ready to be switched-on (i.e. deploying the arms, switching on heater lines etc). As such the LEOP is briefly described here for information purposes. The nominal LEOP sequence ([AD09]) contains the following steps Launch Launcher separation o 6 minutes before centre of Hartebeestshoek, SA, visibility Initialisation and solar array (SA) deployment o PLM survival heater lines 8 & 16 switched-on ([AD10]) 1 st safe hold mode (SHM) o AOCS 1 st phase RDP0/RDP1/SPP o BBQ AOCS mode and reduced control-command (CC) mode Payload deployment (see below) Second SHM Star acquisition mode (STAM) o Preparation in 2 nd BBQ/reduced o PLM in passive state (from platform point of view) Power applied to payload heater lines ([AD10]) 3 & 15 for Arm A 6 & 12 for Arm B 4 & 11 for Arm C o Transition from BBQ/reduced mode to STAM heliocentric/reduced mode o STAM heliocentric mode Earth-centred attitude (32.5 tilt in orbital plane) o Transition from STAM HELIO to STAM RAMP: G2 TCs o Transition from STAM heliocentric to STAM geocentric: G2 o Transition from STAM heliocentric to STAM geocentric: G1 TCs o STAM geocentric Nominal AOCS mode o Yaw-steering attitude law Calibration manoeuvre for thrusters 5 th day of LEOP Orbit correction ([AD13])

28 Page: 28 / 195 The MIRAS arms are deployed during the barbecue (BBQ) phase, based on the Sun Pointing Phase (SPP). The SPP aligns the satellite -x-axis towards the sun with no satellite body kinetic momentum. The +x-axis is aligned with the physical boresight direction, or normal, of the MIRAS antenna array ([AD01]). The payload deployment is defined in [AD11] from which the FCPs are built ([AD12]). The deployment is currently under review. The instrument may be switched-on for a few minutes (4-5) one orbit before the deployment in order to obtain more information on the temperatures around the hinges. In addition, if the instrument is put into U- noise mode (the internal calibration mode used in on-ground testing) we can obtain data on the U-noise susceptibility to (extreme) temperatures in the same I-HKTM. This is sensible since the instrument will not measure any external targets in its foldedup configuration. Note that the instrument is switched-off again before the deployment sequence. The survival heater lines maintain the PLM temperature at -10 C. The MIRAS arm heater segment lines are switched-on using TCs at 10 minute intervals. Note that in this context the hub elements are included as a 4 th segment for each arm. These heaters maintain the PLM temperature between -7 C and -5 C by using the main thermal heaters. (See MIRAS switch-on details in next section.) CASA will support ESA during this first switch-on and arm deployment. The satellite is injected directly into the reference orbit ([AD01]). However, it is to be expected that some orbit corrections are required, depending on the launch dispersions. These activities are defined relative to the nominal attitude ([AD13]). The eccentricity and semi-major axis can be adjusted together using in-plane manoeuvres. The inclination correction requires an out-of-plane manoeuvre. The nominal attitude will be achieved within 4 days ([AD09]). The orbit corrections will comprise ([AD13]) 2 or 3 in-plane manoeuvres 1 or 2 out-of-plane manoeuvres A minimum waiting period of 2 to 3 days (depending on the magnitude of the manoeuvres) between successive manoeuvres is required for orbit determination and preparation of the next manoeuvre. The orbit acquisition will therefore take between 8 and 17 days ([AD13]). The final inplane manoeuvre will be performed after the out-of-plane manoeuvres. 4.2 Platform Check-out The objective of this sub-phase is to verify and optimise the operations of the platform. These activities should be completed as soon as possible. Often the acquisition of the operational orbit is included in this sub-phase. In practice there is an overlap with the LEOP since some check-out activities do not need the nominal orbit.

29 Page: 29 / 195 Similarly, this sub-phase can continue in parallel to the payload activities (see Figure 3.4.2). It is expected that this phase will last for 2 weeks, and overlap with the first 2 weeks of the instrument activities. Following the meeting at CNES on the 7 th April 2009 it became clear that CNES want to test the various pointing strategies to be used in external manoeuvres before they are used operationally. The 3 cases to be tested are: Inertial pointing for 2 minutes (a short period so the reverse slew is opposite to normal) Inertial pointing for 30 minutes (slightly longer than nominal, see section 4.6.4) Zenith pointing for 1.1 orbits (see section ) The detailed planning and implementation for this sub-phase is a CNES responsibility. They propose to do all 3 cases during week 2 of our schedule. Note that the payload is on during these activities (since it is switched-on during the last days of LEOP). Some support from the payload team may be necessary, for example, when investigating overall power or thermal aspects. The effect of the S-band transmitter interference will be checked during the platform commissioning using two zenith pointing external manoeuvres. During the payload commissioning a nominal external calibration using inertial pointing will check the X- band transmissions and the effect of the star tracker (STR). The first star tracker will remain on continuously and the second one will be switched on and off. For both activities the impact on the correlator signals will be assessed using the UPC TS and the L1PP. This data analysis will be performed by UPC and Deimos. To keep things simple from a commanding point of view, the same timeline is used for the SADM (section ) and X-band/STR RFI (section ) tests using the Deep Sky as a target. These activities can be considered to be completed satisfactorily once the platform, SOGS and the S-band TM & TC have been shown to operate correctly. Data analysis will be performed in both real-time and offline using the S-band TM and X-band telemetry. 4.3 Payload Check-out The objective of this sub-phase is to bring the payload into an operational condition, fully functional and ready to support internal parameter tuning. These activities will be part of the SODAP sub-phase (see Table 4.1). Nominally, this sub-phase begins once the orbit acquisition has been completed, i.e. after LEOP. However, there is an overlap with LEOP with regard to the initial switchon of the heater lines in order to keep the payload in a survivable thermal environment.

30 Page: 30 / 195 The baseline timeline for the payload switch-on is to wait until all orbit correction manoeuvres have been completed. This will allow the actual orbit to be known and the details provided to the SPGF so that the downlink commands can be generated. The baseline switch-on scenario was presented in [AD14]. This has subsequently been modified in order to improve (smooth) the power demand profile ([AD35]). It is assumed that the arm heater segment lines have been switched-on during the STAM phase. The arm heaters remain on during an out-of-plane manoeuvre. Starting from the nominal attitude the correlator and control unit (CCU) is switched-on. This is controlled by commands known as High Priority Commanding (HPC) which are made available from the platform. The CCU performs two main tasks: general payload operation control and digital correlation of raw scientific information ([AD15]). The central processing unit (CPU), digital correlator (CORR) and mass memory unit (MM) are activated and their settings (nominal or redundant) define the CMN configuration. Once the CCU receives power, the on-board software (OBSW) is activated and the CCU is running in an initialisation state. The switch-on activities should be performed during visibility with an S-band ground station. The first thing the OBSW does is to initialise the CCU hardware (HW), that is to configure itself, and then checks which arm electronics (main or redundant) are currently powered. The OBSW does this by trying to communicate first to a main command and monitoring node (CMN) ([AD16]) and then to the corresponding redundant CMN. The first CMN to answer defines the redundancy configuration for all future communications. The OBSW continuously loops around all 12 CMNs trying to get an answer from one of the chains. The CCU (strictly the OBSW) remains in this initialisation state until it has received an acknowledgement from all the CMNs. The arm electronics, comprising the command and monitoring nodes (CMNs), are then switched-on, arm by arm, also during visibility to allow the S-band telemetry to be assessed in real-time. The first two arms, A and B, are switched-on with a one minute interval. Once these CMNs are switched-on the heat dissipation from their power consumption will cause the thermostats controlling the arm heater segment lines to switch off. The thermal control threshold, or target set point, is set to 10 C. This intermediate set point is used due to constraints on the battery charging/discharging management. Note that the switch-on of the CMNs requires the clock signal from the CCU to be available. To avoid the X-band switch-on, and hence another power demand, the ground station detection algorithm is disabled (see section 4.4). This should be performed before the CMNs are switched-on. The CMNs in arm C are then switched-on 1 minute later and during visibility. The OBSW will identify that all the CMNs are now active and so the next state can be instigated. The active thermal control from the CMNs now starts. The CCU is acquiring some payload auxiliary data as soon as it is switched-on. Until the X-band

31 Page: 31 / 195 downlink is activated, either by TCs or by using the autonomous mode, the only data downlink is the S-band telemetry. After a further 2 (TBC) hours the ground station detection algorithm could be enabled again (see section 4.4). It is planned to use TCs to control the data downloading and only utilise the autonomous mode much later in the IOCP. Finally, after 6 hours, to allow the batteries to recharge, the thermal control set point is set to 22 C. After 8 hours the instrument should be at the nominal operating temperature. The activation of the X-band downlink (via the ground station detection algorithm) could be based on the ability or need to examine the effect of the changing thermal environment. This assessment could be performed for the 10 C set point before raising it to 22 C. However, the orbital timeline is such that the data downlink opportunities to the XBAS at ESAC are not compatible with the switch-on scenario. The CCU controls the transmission of the stored data over the X-band interface ([AD16]). The data is formatted into CCSDS source packets ([AD15]) and (during nominal measurement mode operations) comprises the science data and the ancillary data ([AD03]). A total of 24 science data packets and 1 ancillary packet are produced for each 1.2s integration period, or epoch. Additionally, the CCU produces PUS HKTM ([AD17]). These data sets are available via both the S-band and X-band downlinks, the latter being configurable. The PUS- HKTM packets comprise start-up telemetry or application software (ASW) telemetry ([AD03]). The start-up telemetry, containing the health status and memory dump, is produced by the start-up software between the power-on and the application software taking control (approximately 10 s later). The PUS packets containing the ASW telemetry are encapsulated in packets of 476 bytes for X-band and 1024 bytes for S-bands. These PUS housekeeping packets contain the ancillary data (422 bytes) and additional instrument management and software information ([AD03]) leading to a total size of 546 bytes. Thus, the downlinked packets (in either band) may contain data from more than one housekeeping packet. The ASW starts in an initialisation mode prior to beginning the instrument initialisation. This status is reported in the instrument mode parameter within the ancillary packet. During the switch-on procedure the instrument will be in the instrument initialisation mode when the CCU is interrogating the CMNs. The start-up telemetry is only available through the S-band downlink, whilst the housekeeping telemetry is available through both downlinks. On-ground the PUS data can be ingested by the PLPC/PXMF system, which is based on the SCOS-2000 monitoring and control system. The PLPC performs the monitoring of the S-band TM, whilst the PXMF performs the monitoring of the X-band housekeeping data. The PXMF can also ingest the S-band TM (from the PLPC). The PUS start-up telemetry can be assessed by the PLPC, or the file can be manually

32 Page: 32 / 195 examined (e.g. using a hex dump). It is not considered necessary to develop specific tools to analyse the start-up data since the amount of data is minimal. Prior to the X-band downlink being available the switch-on activities can only be monitored by the S-band data stream. The payload switch-on can be considered to be completed satisfactorily once the instrument in is Dual Polarisation measurement mode and the science and auxiliary data is being recorded on-board in the memory and the corresponding TM packets are produced. In case of future modifications to the switch-on procedure, reference should be made to the Flight Operations Manual ([AD40]). Data analysis will be performed in both real-time and offline using the S-band PUS- HKTM. The telemetry includes data on the MM (number of packets and read/write pointer addresses) and the number of packets created for each data type (science, ancillary, S-band and X-band). Note that these data values are outside the ancillary table area of the PUS-HKTM. CASA will verify that the nominal switch-on sequence has been followed. ESA and CNES will also analyse data from this activity Phasing of Payload Switch-on As mentioned previously, the CCU begins acquiring payload auxiliary data as soon as it is switched-on. It would be useful to acquire initial confirmation of the payload operation as early as possible. Originally, the baseline timeline was to switch-on the payload only when all the orbital manoeuvres have been completed and the final orbit is achieved. However, by switching-on during the last few days of the LEOP we can gain these days to support the initial payload testing. Thus, it is proposed that the payload is switched-on, and left on, after completion of the out-of-plane manoeuvres, but before the final in-plane manoeuvres. This may complicate the planning since the orbit is not the final one. However, we are not planning to use the X-band data stream during these initial tests. The data is limited to the S-band PUS-HKTM unless the X-band downlink is activated. Since the orbit will not be the final one it could be necessary to manually command downlinks through X-band even if it were to be activated. The X-band data provides the science data (the digital correlation counts) and ancillary data in addition to the PUS-HKTM (which contains the ancillary data). This is not essential for verification of the instrument switch-on, but is necessary for verifying the subsequent activities. In particular, the science data needs to be verified as one of the early payload characterisation activities, thereby limiting the benefits from too early a switch-on.

33 Page: 33 / X-Band Switch-on The operational X-band downlink scenario is based on open loop operations ([AD02]). This assumes that the payload data is dumped to the ground each time the satellite is within the XBAS visibility. This strategy can be achieved using either the planning tools within the SPGF or the autonomous algorithm within the on-board software. The SPGF considers the complete mission planning, including constraints, and computes the XBAS visibility from which a downlink plan is generated. The PLPC generates the necessary PLM TCs which are passed to the CCC for uplink to the satellite. The on-board software includes an algorithm which computes when the satellite is in the reception capability of a designated ground station (nominally the XBAS). The on-board X-band autonomous mode (OAM) downlink is initially de-activated during the payload switch-on (see section 4.3). In particular, this means that the autonomous algorithm must be inhibited. The key point for the X-band downlink deactivation to be cancelled is the entry into a measurement mode, namely Dual Polarisation measurement mode at the end of the switch-on sub-phase. Once activated, by command from the ground, the data downlink is performed according to the commanding or every time SMOS is visible from the XBAS in the autonomous mode ([AD13]). Both the baseline downlink scenario, the ground commanding mode (GCM) using TCs from the SPGF/PLPC and the optional autonomous programming scenario can be modified to operate using only ascending or descending passes. It is proposed to test both the modes in the IOCP. The telemetry (in the ancillary packet inside the PUS-HKTM available by S-band) cannot be monitored in real-time. However, this is not foreseen to cause any problems. The main constraint for the X-band activation is to wait until the instrument has reached the nominal thermal condition (22 C). This will avoid another potentially large instantaneous power demand when the downlink operates in parallel to the other switch-on activities. Additionally, it will not increase the energy demands during the switch-on sub-phase orbits when the thermal conditions are being configured. The X-band switch-on can be considered to be completed satisfactorily once the measurement data (science and auxiliary data packets) are being received on-ground. Data analysis will be performed in both real-time using the S-band PUS-HKTM and offline using the X-band data sets (science, ancillary and PUS-HKTM). It should also be noted that the autonomous mode is currently only capable of operating with one ground station, whereas multiple stations will be used after launch when the NRT acquisition is running (see section 4.5). Consequently, if more than one ground station is being used (i.e. the baseline approach) the autonomous mode would only be applicable for one station. There are currently no plans to change this.

34 Page: 34 / X-band Data Acquisition Once the instrument is switched-on and the X-band downlink has been activated the data links can be verified. The S-band uplink for TCs and S-band and X-band downlinks (for TM and science data respectively) can be verified in parallel to the instrument activities. However, it is necessary to check the X-band RF downlinks as a precursor to getting L0 data in the ground segment. During these tests there is no guarantee that the data will reach the L0 processor but it does not rule it out completely (i.e. no instrument tests which require data on-ground should be performed at the same time). In order to keep the scenario simple it is planned to test the RF downlinks in a sequential order (first ESAC then SVALSAT or vice-versa) before trying a combined scenario (e.g. the NRT mixed ground stations). By only using one ground station at a time (initially) it simplifies the data chains up to the L1 processor, thereby making analysis of any problems easier. This scenario is shown in Figure This has subsequently been superseded by Figure CASA will provide support to ESA for the initial downlink at ESAC. So, the timeline starts with two RF test campaigns of ESAC and Svalbard (note there is a delay between the two campaigns to allow personnel to travel between the two sites. After each RF campaign there can then be a test using just one ground station to examine the data flow to the L0/L1 processor(s). Each of these single scenario tests (identified as MINI in the diagram) has the RF test as a precursor. The combined scenario test (identified as ROBUST in the diagram) has both single scenario tests as precursors. This will combine data sets from both ground stations and so it is preferable to test each individually first. Within the combined scenario test there may be several different combinations of dumps to ESAC and Svalbard. ESAC RF ESAC MINI T R A V E L SVAL RF SVAL MINI ROBUST Figure 4.5.1: Nominal Timeline for Testing Data Links The RF test campaign at Svalbard does not have to happen immediately after the ESAC test, nor does it have to precede the ESAC MINI test. Indeed, by careful choice of the RF test configuration (at Svalbard) the data can be dumped to ESAC at the same time.

35 Page: 35 / 195 The RF tests are scheduled to last 3 days each. The MINI test scenarios are planned to last one week each (in line with the general planning of the IOCP). The ROBUST scenario is then applicable for the rest of the IOCP, although this scenario includes several combinations of ground stations. The MINI tests (and the ROBUST test) do not affect the instrument tests and so can be performed in parallel. This approach to the testing requires the NRT acquisition (at Svalbard) to be available from launch. This is so that should one ground station fail, the data downlinking can be transferred fully to the other link. Thus, to ensure that all data is received (at the L1 processor), it is proposed that the RF tests are both performed before either of the single station tests. In this way we safeguard against long delays in data acquisition should one ground station fail. The ESAC MINI campaign (and RF test) will allow the XBAS to be commissioned and ensure that all data is acquired. To achieve this all downlink opportunities (i.e. 4 passes per day) should be utilised. Similarly, the Svalbard MINI campaign will allow that downlink (and links to ESAC) to be commissioned. There will obviously be a trade-off to be made between instrument activities (e.g. calibration) and number of downlink orbits. In order to be ready in time, the go-ahead for the Svalbard station needs to be made some 2-3 weeks (or even longer) prior to the RF test campaign. This is then neatly in line with the launch date and the length of the LEOP. The sequential approach to the introduction of the multiple acquisition stations is considered to be the simplest and minimises risk. Note that any data downlinked to either of the ground stations during the RF testing cannot be essential since it may be lost. This potential loss of data (during the second RF test) can be circumvented by dumping all the data in the usual manner to the first ground station (the XBAS at Villafranca) using the nominal strategy, and using commands to dump specific sections of memory during the RF test of the second link (the NRT at Svalbard). In this way no science data is lost (since it is all downlinked to the XBAS) and so the NRT commissioning can be performed in parallel with other instrument-led tasks. Once the second (NRT) downlink has been proven to work the dump strategy can be changed (during the second MINI scenario and the ROBUST scenario). This approach will also allow the quality of the two downlink routes to be assessed, during the ROBUST scenario, since the same set of data could be downloaded through each route if the dump strategies are set-up accordingly. Alternatively, the NRT downlink could be verified first and the XBAS secondly. However, this choice cannot be made until the NRT downlink is up and running, which should be in the final quarter of These activities will be performed by ESA with support from other team members where appropriate (e.g. CASA and Deimos).

36 Page: 36 / 195 Note that the 3 downlink scenarios ([AD01]) are now redundant and should be superseded by a verification of the NRT system and its impact on the ground processing throughput. Additionally, the autonomous algorithm should be examined in order to demonstrate whether it helps to simplify the planning for the subsequent nominal operations phase. This activity can be considered as a supporting activity, later in the IOCP, to the characterisation of instrument measurement modes (section ) and to the ground segment verification (see section 4.10). In other projects (e.g. ENVISAT) the initial data acquisition is considered together with the instrument switch-on as forming the switch-on and data acquisition phase (SODAP). In this case the data acquisition supports several activities from the switchon to the instrument verification. The number of ground stations used has an impact on the time delay between the instrument acquiring data and it being available for on-ground processing. Using only the XBAS the data can be up to 10 hours old when acquired on-ground. When the NRT acquisition station is used data is received every orbit, reducing the latency to 100 minutes (strictly it is more than one orbit (100 minutes plus the time between the two dump sites). However, the routing of data from the acquisition stations to the processors is more complex. Using the success oriented philosophy for the IOCP it is assumed that each orbit dump will be successful. In cases when a dump fails, the instrument measurements may need to be repeated if the data is a prerequisite for other processing. A number of test dumps (i.e. using non-essential data) should be performed soon after the instrument switch-on in order to verify the XBAS acquisition. These dumps are the RF test scenarios. Thus, the first week following instrument switch-on is a dead zone for other instrument activities (due to the potential loss of the X-band data). The exact timeline for events during these X-band tests in the first 3 weeks is under the responsibility of the SODAP team, who are currently working on the fine details. As far as this plan goes, it is envisaged that all SODAP activities can be completed in the first 3 weeks (plus the 2 days during the LEOP). The SODAP activities are defined in [AD50] which comprises the test descriptions and the timeline (based on downlink opportunities) Failure Scenario Should the nominal timeline presented above fail for any reason, we need to have failure cases identified so that the receipt of data by the L0/L1 processors is guaranteed. Failure to get data to the L1 processor(s) is a non-recoverable situation, so we need to have contingency procedures in place prior to launch. Should an RF test fail the other ground station should take up the responsibility to acquire all data. Similarly, if a MINI scenario runs into a problem the other ground station should take up the responsibility to acquire all data.

37 Page: 37 / 195 In such cases, the RF test and MINI test scenario should be replayed at an appropriate slot. The only downside of this is the delay in bringing the NRT scenario fully into operation SODAP Schedule The schedule for the SODAP activities is presented in a separate timeline (from the rest of the IOCP). However, it should be read in conjunction with this plan (and the main IOCP timeline). The overall scheme for SODAP activities is shown in Figure They start with a health check of MIRAS during the end of the LEOP before entering the SODAP weeks when the RF downlinks at ESAC and Svalbard are tested. Figure : SODAP Timeline (High Level)