GALILEO GALILEI (GG) SYSTEM ENGINEERING PLAN DEL-31

Transcription

1 ISSUE : 02 PAGE : 1/34 GALILEO GALILEI (GG) SYSTEM ENGINEERING PLAN DEL-31 Written by Responsibility F. Gilardi Author Verified by A. Anselmi Checker Approved by Product Assurance Configuration Control Design Engineer System Engineering Manager A. Anselmi Study Manager Documentation Manager R. Cavaglià The validations evidence are kept through the documentation management system.

2 ISSUE : 02 PAGE : 2/34 ISSUE DATE CHANGE RECORDS AUTHOR 1 6-Mar-09 First issue delivered at IRR FG 2 08-Jun-09 Issue submitted to PRR

3 ISSUE : 02 PAGE : 3/34 TABLE OF CONTENTS 1. INTRODUCTION SCOPE APPLICABILITY REFERENCES APPLICABLE DOCUMENTS STANDARDS ASI REFERENCE DOCUMENTS GG PHASE A2 STUDY NOTES PROJECT OVERVIEW PROJECT OBJECTIVES AND CONSTRAINTS Background Program Objectives Satellite Architecture Platform Description Payload Description Project Lifecycle Project Lifecycle Support Project responsibilities and organization Project Drivers National and International Regulations Verification and Validation Strategy GG EVOLUTION LOGIC PROJECT PLANNING, PHASES AND REVIEWS Phase B Phase C/D Phase E Phase durations and reviews PROCUREMENT APPROACH Recurring Items Items Requiring Development and/or Qualification Payload Micro-Newton Thrusters Spin Sensor Application Software Software Simulators SYSTEM DESIGN APPROACH SYSTEM ENGINEERING INPUTS... 20

4 ISSUE : 02 PAGE : 4/ SYSTEM ENGINEERING OUTPUTS System Engineering Strategy System Design Major Outputs and Reviews Project Development Design and Manufacturing Activities Assembly, Integration and Ground Test Activities In Orbit Acceptance Model Philosophy System and Platform Model Philosophy Payload Model Philosophy Units and Subsystems Model Philosophy IMPLEMENTATION AND RELATED PLANS SYSTEM ENGINEERING TASKS DESCRIPTION Work Packages RELATED PLANS Programmatic Plans Verification Plans System AIV Plan Payload AIV Plan Subsystem/unit AIV Plan Engineering Discipline Plans Operations Plans SYSTEM ENGINEERING FOR THE FOLLOWING PHASES GG MASTER SCHEDULE GG KEY MILESTONES ACRONYMS...33

5 ISSUE : 02 PAGE : 5/34 LIST OF FIGURES FIGURE 3.1-1: SECTION THROUGH THE SPIN AXIS OF THE GG SATELLITE...11 FIGURE 5.2-1: VERIFICATION LOGIC AND LINKS...27 FIGURE 5.2-2: DEVELOPMENT PLAN AT SATELLITE LEVEL...28 FIGURE 6.1-1: GG MASTER SCHEDULE...31 LIST OF TABLES TABLE 3.3-1: GG PHASE DURATIONS...17 TABLE 6.2-1: GG KEY EVENTS...32

6 ISSUE : 02 PAGE : 6/34 1. INTRODUCTION 1.1 SCOPE This document is submitted in partial fulfilment of Work Package 1A-ADA of the GG Phase A2 Study. The requirements for the contents of the system engineering plan (SEP) are given in Annex D of ECSS-E-ST-10C, Space Engineering - System Engineering General Requirements, 6 March 2009 [SD 1]. According to this document, the SEP shall describe the approaches, techniques, tools, organization, planning and scheduling of the technical effort to accomplish the project objectives. The SEP shall describe all anticipated contributions to the System Engineering effort and be updated during the course of the project to reflect any evolution in the system engineering implementation. 1.2 APPLICABILITY The SEP describes all the project phases, starting from phase B kick off and ending with delivery of the spacecraft to the Customer. Through Phase A2, this draft SEP was built up with a view to preparing a consolidated version to be submitted to the customer for approval, prior to the beginning of Phase B.

7 ISSUE : 02 PAGE : 7/34 2. REFERENCES 2.1 APPLICABLE DOCUMENTS [AD 1] ASI, Progetto Galileo Galilei-GG Fase A-2, Capitolato Tecnico, DC-IPC , Rev. B, and applicable documents defined therein 2.2 STANDARDS [SD 1] ECSS-E-ST-10C, ECSS System Engineering General Requirements [SD 2] ECSS-E-10-02A, ECSS Space Engineering Verification [SD 3] ECSS-M-00-02A, Space Project Management [SD 4] ECSS-E-30, Space Engineering - Mechanical - Part 1: Thermal [SD 5] ECSS-E-30, Space Engineering - Mechanical - Part 2: Structural [SD 6] ECSS-E-30, Space Engineering - Mechanical - Part 3: Mechanism [SD 7] ECSS-E-30, Space Engineering - Mechanical - Part 5: Propulsion [SD 8] ECSS-E-30, Space Engineering - Mechanical - Part 6: Pyrotechnics [SD 9] ECSS-E-30, Space Engineering - Mechanical - Part 7: Mechanical Parts [SD 10] ECSS-E-30, Space Engineering - Mechanical - Part 8: Materials [SD 11] ECSS-E-40 Part 1, Software Engineering Standards [SD 12] ECSS-E-ST-60-10C, Control Performance [SD 13] ECSS-Q-00A, Space Product Assurance [SD 14] ECSS-Q-ST-70-01C, Cleanliness and contamination control, 15 November 2008 [SD 15] ECSS-E-HB-21A, Design requirements for the optical system 2.3 ASI REFERENCE DOCUMENTS [RD 1] GG Phase A Study Report, Nov. 1998, revised Jan. 2000, available at: [RD 2] Supplement to GG Phase A Study (GG in sun-synchronous Orbit) Galileo Galilei-GG : design, requirements, error budget and significance of the ground prototype, A.M. Nobili et al., Physics Letters A 318 (2003) , available at: [RD 3] A. Nobili, DEL001: GG Science Requirements, Pisa, September 2008

8 ISSUE : 02 PAGE : 8/ GG PHASE A2 STUDY NOTES [RD 4] SD-RP-AI-0625, GG Final Report / Satellite Detailed Architecture Report, Issue 1 [RD 5] SD-RP-AI-0626, GG Phase A2 Study Executive Summary, Issue 1 [RD 6] SD-TN-AI-1163, GG Experiment Concept and Requirements Document, Issue 3 [RD 7] SD-RP-AI-0620, GG System Performance Report, Issue 2 [RD 8] SD-TN-AI-1167, GG Mission Requirements Document, Issue 2 [RD 9] SD-RP-AI-0590, GG System Concept Report (Mission Description Document), Issue 3 [RD 10] SD-SY-AI-0014, GG System Functional Specification and Preliminary System Technical Specification, Issue 1 [RD 11] SD-RP-AI-0631, GG Consolidated Mission Description Document, Issue 1 [RD 12] SD-TN-AI-1168, GG Mission Analysis Report, Issue 2 [RD 13] GG-TN-DTM-002, Galileo Galilei Satellite - Design & Structural Analysis Report, Issue 1 [RD 14] SD-RP-AI-0627, GG Thermal Design and Analysis Report, Issue 1 [RD 15] SD-RP-AI-0268, GG System Budgets Report, Issue 1 [RD 16] SD-RP-AI-0621, Technical Report on Drag and Attitude Control, Issue 2 [RD 17] TL25033, Payload Architectures and Trade-Off Report, Issue 3 [RD 18] SD-RP-AI-0629, Technical Report on Simulators, Issue 1 [RD 19] GG.ALT.TN.2003, FEEP Microthruster System Technical Report, Issue 1 [RD 20] TASI-FI-44/09, Cold Gas Micro Thruster System for Galileo Galilei (GG) Spacecraft - Technical Report, Issue 1, May 2009 [RD 21] SD-RP-AI-0630, Spin Sensor Design, Development and Test Report, Issue 1 [RD 22] SD-TN-AI-1169, GG Launcher Identification and Compatibility Analysis Report, Issue 1 [RD 23] ALTEC-AD-001, GG Ground Segment Architecture and Design Report, Issue 1 [RD 24] SD-TN-AI-1218, GG Preliminary Product Tree, Issue 1 [RD 25], GG System Engineering Plan (SEP), Issue 2 [RD 26] TAS-I, Payload Development and Verification Plan, Issue 1 [RD 27] SD-PL-AI-0228, GG System Verification and Validation Plan, Issue 1 [RD 28] SD-TN-AI-1219, Report on Frequency Management Issues, Issue 1 [RD 29] SD-RP-AI-0632, GG Mission Risk Assessment And Mitigation Strategies Report, Issue 1 [RD 30] SD-RP-AI-0633, Report on Mission Costs Estimates, Issue 1

9 ISSUE : 02 PAGE : 9/34 3. PROJECT OVERVIEW 3.1 PROJECT OBJECTIVES AND CONSTRAINTS Background Galileo Galilei (GG) is a project of the Italian Space Agency (ASI), under consideration for implementation as part of ASI s small satellite series, with launch before 2015 (TBC). The GG mission is a part of the Cosmology and Fundamental Physics project of the ASI Unit on Observation of the Universe, the purpose of which is providing support to the Italian Scientific Community in its participation in the European and worldwide development of knowledge in this field, both by independent projects and by international collaboration. GG participates in the worldwide programme of verifying the founding principles of physics by means of groundbreaking experiments which can only performed in the space environment. The goal of GG is to test the Equivalence Principle (EP) to 1 part in 10 17, more than 4 orders of magnitude better than today s ground experiments. As an EP experiment, GG shares the same goal as the STEP experiment of NASA and the Microscope experiment of CNES. Its contribution to the field consists in an original and innovative experiment concept, which promises an accuracy and precision unparalleled by any other experiment. A one-g version of the differential accelerometer designed to fly onboard the GG satellite, called the GGG experiment, is currently operational in the INFN laboratory in San Piero a Grado, Pisa. It is designed to test the main features of the space instrument in a laboratory experiment. The GGG experiment is carried out with Istituto Nazionale di Fisica Nucleare (INFN) funding and ASI support. The GG mission and satellite have already been studied at both scientific and industrial level. Between 1997 and 2000, a mission based on an equatorial orbit was studied under ASI contract [RD 1]. In 2001, adaptation of the mission to a sun-synchronous orbit, driven by launcher availability, was addressed [RD 2]. The successful launch of Agile has demonstrated the feasibility for ASI of launching, at low cost, a small satellite into near perfectly equatorial orbit. Thus the equatorial orbit, which was preferred anyway because of simplicity of design and operation, can be taken again as the GG baseline. The GG project of ASI is carried out in tight collaboration with INFN. ASI and INFN have signed an agreement for collaboration in a number of scientific projects. In the implementation phases of GG, if approved, ASI and INFN will sign a specific agreement which will define the contributions by each institution to the mission.

10 ISSUE : 02 PAGE : 10/ Program Objectives The main objectives of the GG program are as follows: To carry out a test of the Equivalence Principle with sensitivity of a least 1 part in 10 17, in low, near-equatorial, near-circular Earth orbit, for a duration of at least 1 year; To design, develop, and test a small satellite, devoted to the above objectives, over a time span (Implementation Phase) not exceeding 3 years, within a level of resources commensurate with that of a small satellite program of ASI; To launch and operate the satellite using as much as possible the infrastructure and resources of ASI; To use this opportunity to advance the implementation and use of Italian technology and know-how in the service of an outstanding scientific project Satellite Architecture Functionally the GG Satellite is defined as a modular product. The whole Satellite is made up of two modules: Platform (or Service Module) and Payload (Pico Gravity Box). At lower level each module is composed of subsystems, each subsystem can be composed of one of more units plus auxiliary parts. In the next sections the two modules are briefly described Platform Description The spacecraft must provide suitable accommodation to the experiment, provide specific and stable mass properties, and shield it from thermal and dynamic perturbations within specified limits. The cylindrical symmetry of the test masses and their enclosure (Pico-Gravity Box, PGB), and the spin required to provide high frequency signal modulation, lead to a spacecraft of cylindrical symmetry too, stabilized by one-axis rotation about the symmetry axis. The spacecraft body is about 1.5 m wide and 1.5m high. The experimental apparatus is accommodated in a nested arrangement inside the body. The structure is made up of a central cylinder and an upper and lower truncated cone. The upper cone is removable to allow the integration of the PGB with its suspension springs; the lower cone supports the launcher interface ring. The equipment is mounted to the central cylinder and to the upper and lower cone. The solar array is made of two cylinders separated by a central belt for mounting equipment, including thrusters and sensors; this solution also allows a suitable distribution of thermal covers and radiators to realise an efficient thermal control.

11 ISSUE : 02 PAGE : 11/ Payload Description A differential accelerometer for testing the Universality of Free Fall (UFF) is placed inside the spinning top, i.e. the satellite. The accelerometer is mounted inside the so called Pico Gravity Box (PGB) which in turn is suspended inside the satellite, as shown in Fig Figure 3.1-1: Section through the spin axis of the GG satellite The accelerometer (green and blue test masses) is mounted inside the Pico Gravity Box (PGB) which in turn is suspended inside the satellite Project Lifecycle The GG project will be implemented in the following main steps: System Definition Phase, that includes the definition of the GG flight system and its relevant support equipment and the finalization of the System and Payload design Development and Production phase that includes the detailed design, the development, production, verification and delivery of the GG flight Satellite with the Payload installed on it, the associated support equipment, and the launcher adapter. Launch and in orbit commissioning, that include the launch preparation, the launch itself and the system checkout and calibration in the early orbit phases The operative life, where the scientific measurements will be acquired, stored, analyzed until the end of the mission.

12 ISSUE : 02 PAGE : 12/ Project Lifecycle Support Several elements shall support the project during its lifecycle. The main elements will be as follows. GG Payload Prototype on the Ground (GGG): is an experiment to test the Equivalence Principle with an apparatus very similar to a prototype of the payload designed for the GG space experiment. The experiment is carried out at the University of Pisa and will be used as a development model for the flight model. GG Ground Segment: it provides all the necessary features to ensure the satellite control during the mission and the scientific data acquisition, storage and analysis. It is composed of the following subsystems: Ground Stations provide the necessary space to ground communication for TM receiving and TC uplink. They also provide the satellite tracking information to be used in support of the satellite orbit determination as well as local storage of on board stored TM to be subsequently transmitted to OCC. The baseline is to use the ASI GS in Malindi. Operations Control Centre (OCC) is responsible for the overall execution of the GG mission operations in terms of mission planning, spacecraft monitoring and control, orbit and attitude determination, P/L monitoring and control. The OCC will also route the scientific telemetry to the SOC and will receive the P/L command requests from the SOC to be subsequently processed and sent to the satellite. Science Operation Centre (SOC) is responsible for the scientific data processing and analysis, and for the generations of the scientific operations sequence to be executed on board. Ground Support Equipment (GSE): the GSE includes all the special test equipments needed to support the activities on ground on GG and on its components. The GSE are subdivided in: EGSE: Electrical Ground Support Equipment MGSE: Mechanical Ground Support Equipment FGSE: Fluidic Ground Support Equipment OGSE: Optical Ground Support Equipment (if any). Special tools used during the GG integration activities on ground like Break Out Boxes, Cable Extensions, jumpers, etc Standard laboratory equipments needed to perform all the electrical measurements on the items under test, like oscilloscope, multi-meters, frequency spectrum analyzer, etc Facilities: during all its lifecycle on ground GG and its flight components will use different facilities to perform testing activities like thermal vacuum chambers, shakers, acoustic chambers, anechoic chambers. Furthermore, all the flight items will be subjected to a Cleanliness Control Plan and to a Quality Control. Consequently the facility used by the prime contractor and its subcontractors shall be conform to these requirements. In particular all the items qualified to flight shall be maintained in a qualified clean-room (typically class 8). At system level the baseline is to use the following facilities:

13 ISSUE : 02 PAGE : 13/34 TAS-I Turin Clean Rooms for PFM Satellite I&T and system testing A dedicated facility to perform the environmental test campaign that will be chosen in order to satisfy the GG environmental test requirements The VEGA facilities in Kourou to support the Launch Campaign. Simulator: Satellite and Payload simulators, both HW and SW, will be used during the project lifecycle when needed to consolidate the design, verify requirements in advance respect to the HW manufacturing, execute test not performable on real HW. Standard engineering mathematical tools will be used to support the project development Project responsibilities and organization This SEP assumes the following organization and responsibilities. In the frame of GG project, TAS-I Torino will be the prime contractor, having in charge the system design and the Satellite development and validation until its delivery to the customer TAS-I Milano will have in charge the Payload development and verification until its delivery to TAS-I Torino. Telespazio will have in charge the Ground Segment development, validation and management, and ALTEC will have in charge the management of the scientific product related tasks of the ground segment Project Drivers The project drivers derive from the extremely challenging experiment target: to test the Equivalence Principle up to 1 part in This objective requires on the payload side the capability to measure relative displacements of the two coaxial test cylinders made of different materials by few pico-meters. On the spacecraft side, this goal requires drag-free control to be maintained on a spinning platform by means of finely tuned proportional thrusters National and International Regulations No special rules are applicable to this project.

14 ISSUE : 02 PAGE : 14/ Verification and Validation Strategy The verification activities will be incrementally performed at different levels and in different phases, applying a coherent bottom-up building block concept, from the equipment to the overall system. The verification program will cover all the aspects of flight hardware and software together with the associated ground support equipment and other verification tools. The methods which accomplish the verification of the applicable requirements are, in agreement with consolidated standards: Analysis (including similarity); Test; Inspection; Review of Design. In general, test is the preferred one, but analysis and other methods can be used in lieu of it if test is not possible or the effort of it is unacceptable with respect to cost and/or schedule constraints. 3.2 GG EVOLUTION LOGIC The GG Satellite detailed design definition will start from the preparation of high level (system level) specifications. Starting from these documents lower level specifications (subsystem and unit level) will be prepared as input for the subcontractors. The Subcontractors will provide to the Prime the requested items after completion of relevant development and validation process. All the units, subsystems, parts collected by the Prime will be integrated to compose the final Satellite and validated with the testing campaign at system level. Dedicated reviews and milestones will be defines in the various project phases to lead the above process.

15 ISSUE : 02 PAGE : 15/ PROJECT PLANNING, PHASES AND REVIEWS On completion of phase A, the overall GG project will be continued by means of the following phases: Phase B: preliminary design phase Phase C/D: design, development and qualification phase Phase E: launch campaign, technical support for Satellite on-orbit commissioning Phase B At the beginning of Phase B a revision of Phase A results will be performed, the scientific and technical requirements will be frozen and the whole mission scenario will be frozen. The objectives of this phase are: To complete the review and analysis of the GG requirements and the translation of those into subsystem and unit specifications (a task already initiated in Phase A2). Special care will be put in the evaluation of possible reuse of existing and already qualified items, to reduce the cost and increase the reliability. To complete the trade-offs and to establish/freeze a detailed GG design baseline compliant with the requirements and to update the performance budgets. To consolidate the model philosophy. To complete the management, PA, development, integration, test and qualification plans. To establish a detailed design of the GSE needed for the AIV/AIT campaign on the GG models, considering also the possibility to reuse existing GSE, defining the needed modifications and refurbishment. To initiate (if deemed necessary) scientific breadboarding and test activities on critical items. To initiate procurement of long-lead items (if any). To prepare the GG Preliminary Design Review (PDR) that will be the formal phase closure. Many of the above tasks have already reached a good level of definition in Phase A2, and for this reason the GG phase B is planned to be of reduced duration with respect to a normal Phase B Phase C/D The main objective of this Phase is to implement the designs, the plans and the specifications generated in Phase B into a fully integrated, qualified and tested GG proto-flight model together with all required supporting hardware and software.

16 ISSUE : 02 PAGE : 16/34 The Phase C will be concluded with a GG Critical Design Review (CDR) allowing Formal authorization to start with the GG unit and subsystems procurements and relevant AIT activities. The Phase D will be concluded with the GG Final Acceptance Review (FAR). The objectives of the Phase C/D include in particular: Completion of the detailed GG design, including all its components and the GSE, leading to a successful Critical Design Review (CDR) Completion of all detailed plans and specifications for the Satellite development, integration and qualification activities Development and manufacturing of all equipment items Integration and testing of GG Satellite, according to the specified model philosophy GG environmental test campaign execution, after completion of Satellite integration and functional test activities Preparation of the system reviews (CDR, FAR) Production and delivery inputs to satellite User s Manual Delivery of GG proto-flight model Phase E This phase comprises the activities as GG Prime Contractor to the launch campaign, and to the Satellite in orbit commissioning. The objectives of the Launch Campaign include in particular: Final GG verification at the launch site to check the satellite performance after the shipment: baseline is a shipment to Kourou for launch with VEGA Mating operations with the launcher Combined operation jointly with launcher authority, including final countdown. The formal review that completes the Launch campaign will be the Launch Readiness Review (LRR) that will be held few days before launch. A successful LRR will authorize GG to launch. After launch TAS-I will provide support in the commissioning phase, where the main objectives will be: Overall in orbit check of GG subsystems and functions capabilities GG configuration in operative mode Payload calibration Start of scientific acquisition.

17 ISSUE : 02 PAGE : 17/ Phase durations and reviews According to the master planning, presented in section 6, the durations in Table apply. Table 3.3-1: GG Phase durations Phase Duration Milestones and events Phase B 9 months KO, PDR Phase C/D 36 months CDR, TRR, FAR Phase E 3 months LRR 3.4 PROCUREMENT APPROACH Recurring Items The items procurement philosophy relies as much as possible on recurring items defined as Category A and Category B in ECSS [ND 02]. The procurement of already qualified equipments leads to the possibility of customising existing specifications and defining reduced acceptance programs. This approach gives benefit on schedule and cost aspects. According to the current design and implementation assumptions [RD 27], the following units/subsystems belong to this category: CDMU Transponders PCDU Battery Sun Sensors On Board SW (Basic) Auxiliary Propulsion Harness and connectors EGSE and test equipment MGSE.

18 ISSUE : 02 PAGE : 18/ Items Requiring Development and/or Qualification Due to the GG mission peculiarities some satellite requirements can be reached only using new or not completely developed technologies. In this section the area/items in this category are described. Design and development programs on these items will be particularly accurate. For what concerns Solar Array cells, diodes and interconnecting cables, partial recurrence from previous projects is possible, although the geometry of the solar panels (located on the external cylinder surface and with the cylinder continuously spinning) is a non recurring aspect Payload 1) Accelerometer Assembly This assembly is the core of the satellite, and the GG mission will be the first time such an instrument is flown in space. A similar instrument named GGG (Galileo Galilei on-ground) is is operating in the INFN-Pisa laboratory but has significantly reduced performances with respect to those required for the space instrument GG, mainly due to Earth gravity. However in engineering terms the GGG is an important validation / demonstrator model. The development of the GG accelerometer will take advantage of the GGG instrument, both in terms of specific design and test issues. In addition, the GGG test system (test equipment) will be studied to assess its use and/or upgrading for functional testing of the GG space accelerometer. 2) PGB wireless optical data transmission (ODT) The ODT subsystem is specific for the GG payload. It transmits all data between the payload and the satellite via an optical bi-directional link. On the payload side the ODT is housed in the ECE unit, and on the platform side in the PCE unit. In order to meet the specific design conditions of the ODT an engineering or functional model will be developed. It is proposed to validate the functional conditions of the ODT system by implementing the EM model of the ODT on the GGG instrument. 3) Locking/un-locking mechanisms These mechanisms provide for keeping the sensitive items of the accelerometer blocked during launch. When the final orbit and attitude are reached, the actuators are powered, the locks are released and the accelerometer can be operated. Several sets of mechanisms are required to block all items in the accelerometer. At this preliminary stage of development it is supposed that all sets of mechanisms work on the same principle. It is proposed to develop a breadboard with one set of locking/unlocking mechanism and related electronics (as necessary to control one mechanism).

19 ISSUE : 02 PAGE : 19/ Micro-Newton Thrusters Field Emission Electric Propulsion (FEEP) is the reference system for enacting the drag-free control. FEEP is an electrostatic propulsion concept based on field ionization of a liquid metal and subsequent acceleration of the ions by a strong electric field. FEEP is currently the object of great interest in the scientific community, due to its unique features: sub-µn to mn thrust range, near instantaneous switch on/switch off capability, and high-resolution throttleability (better than one part in 10 4 ), which enables accurate thrust modulation in both continuous and pulsed modes. The development status of FEEP is described in [RD 19]. An alternative solution based on Cold Gas Micro Propulsion (CGMP) is also available [RD 20] Spin Sensor The GG mission requires a specifically designed sensor system, with the capability of measuring a spin rate of 1 Hz with the required relative accuracy of Such performance cannot be provided by ordinary off-the-shelf AOCS devices like star trackers or Sun/Earth sensors. The proposed solution for the mission consists of a camera using a Position Sensing Detector (PSD) for measuring the optical power and the coordinates of the light spot focused on the focal plane. A small telescope endowed with the sensor detects the position of light emitting source from the position of the light spot focused on the PSD. In this way Sun angular position with respect to the sensor reference frame can be evaluated. The proposed spin rate sensor design was the subject of a dedicated breadboard development in Phase A2, which has already provided proof-of-concept [RD 21] Application Software The On Board Application SW will be tailored for the GG mission characteristics. All the new DFACS algorithms will be subjected to a complete validation campaign. This development will benefit from the GOCE experience and may reuse parts of the GOCE flight software. For this reason, an in-house TAS-I software development, including coding, is envisaged Software Simulators A full-scale high fidelity simulator of the GG flight experiment is already available after Phase A2 [RD 18]. This simulator is a fundamental building block of the GG development and verification strategy, and extensive use will be made of it for both performance predictions and

20 ISSUE : 02 PAGE : 20/34 4. SYSTEM DESIGN APPROACH 4.1 SYSTEM ENGINEERING INPUTS The GG design has been developed starting from the following initial inputs: Mission Requirements [AD 1], [AD 2] and [AD 3] Cost Target. Since the project is in phase A there aren t other specific input coming from previous phases. The experiences and the data results coming from the GGG experiment constitute important additional input for the flight experiment development. 4.2 SYSTEM ENGINEERING OUTPUTS The system engineering strategy to satisfy the project requirements presented below, identifying the major project outputs foreseen in the different project phases, starting from the design definition activity up to launch campaign and in orbit acceptance System Engineering Strategy Under consideration of the small-mission class and low cost target, the challenging technical requirements shall be met by a design implementing the following guidelines: Use of standard or recurring on board equipments whenever possible Privileged use of well known technologies Maximum reuse of already tested on board SW Maximum reuse of Mechanical Ground Support Equipment from previous projects Maximum reuse of Electrical Ground Support Equipment from previous projects Maximum reuse of Test SW already developed. The progress status of design and development of satellite, both for technical and management aspects, shall be controlled by proper system design reviews.

21 ISSUE : 02 PAGE : 21/ System Design Major Outputs and Reviews For each system design review proper documentation (data package) will be prepared and delivered in order to permit the evaluation of the progress of project and to evaluate if the project status meets the tasks associated to the relevant design review. For the satellite design and development, the following reviews are planned: Preliminary Design Review (PDR) Critical Design Review (CDR) Test Readiness Review (TRR) Test Review Board (TRB) Final Acceptance Review (FAR) Launch Readiness Review (LRR). a) Satellite Preliminary Design Reviews (PDR) The purpose of the PDR is to provide a presentation of satellite preliminary design either at system level or for all the subsystems (including P/L s), with the preliminary prediction of the satellite performances compared with specified requirements. b) Critical Design Reviews (CDR) The purpose of CDR is to provide an exhaustive presentation of satellite design at system level and for all the subsystems, with the evaluation of satellite predicted performances compared with specified requirements. The evaluation of satellite design and of development status at satellite level will be based on the review of a collection of design and development documents, the CDR Data Package, which shall include as minimum the documents listed below: Satellite Specification; Satellite Design and Development Plan; Satellite Design Description; Satellite HW Matrix; Satellite Test Requirements; Design Verification and Compliance Matrix vs Satellite Specification; Satellite Budgets; Satellite Mission Analysis; Satellite Launcher to System Interface Document; Satellite Reliability Analysis and FMECA; Satellite configuration drawings;

22 ISSUE : 02 PAGE : 22/34 Satellite Interface Documents: electrical, telemetry & telecommand, thermal mechanical, SW, including also the interfaces between Payload and Platform Harness design, layout and configuration Satellite Assembly, Integration and Test Plan; Payloads Design Report; Satellite (EGSE and MGSE) Ground Support Equipment Requirements; Qualification Status of Satellite Equipment. c) Test Readiness Review (TRR) This review is foreseen before the start of satellite integration and ground test activities, in order to release the authorization to start those activities. In order to meet this task, during the TRR, the satellite Prime Contractor shall demonstrate that: all satellite parts, equipment and software products, are available and they have been accepted according to required performances and products assurance standards, all items of Ground Support Equipment (EGSE + MGSE) are available and adequate to integrate and test satellite flight hardware; the iteration and test plans as well as the detailed procedures are available and validated. An additional task of TRR is to verify and validate the qualification status of all satellite parts. The achievement of TRR tasks is based on the review of a collection of documents, TRR Data Package, that shall include as minimum the documents listed below: End Item Data Package for all equipment and satellite hardware; GSE documentation (including EIDP s); Satellite Integration and Test Plan; Satellite electrical and mechanical integration procedures; Satellite test procedures. d) Final Acceptance Review (FAR) This review is foreseen at the end of satellite integration and ground test activities, in order to certify the completion of satellite ground tests, to establish the satellite performances, measured by ground test, and to verify that those measured performances meet the specified requirements. An additional task of FAR is to verify that satellite, with all support documentation, is ready to start the launch campaign e) Launch Acceptance Review (LRR) This review will be held a few days before launch and it is the final formal step to authorize the Satellite launch. This review, which will involve also the Launch Authority, has the purpose to certify that the Satellite and the launcher have successfully completed all the launch preparation activities, including the planned countdown rehearsal.

23 ISSUE : 02 PAGE : 23/ Project Development The main activities foreseen in the frame of project development and finalization are described below Design and Manufacturing Activities These activities are related to design and manufacturing of the units, parts and hardware of the satellite up to starting of integration and ground tests of satellite itself. In particular the following actions are part of this development step: Preparation of design and performance test specification for satellite, subsystems and units; Definition of design standards, qualification/acceptance test requirements and product assurance standards with issue of relevant documentation; Completion of satellite design with analytical verification of achievement of specified performances, with update of satellite or subsystem specifications, if necessary; Completion of unit design with analytical verification of achievement of specified performances, with update of units specifications, if necessary; Build and integration of models, for units or satellite hardware where new design is applied, dedicated to qualification product program, and execution of relevant qualification test plan; Build and integration of flight models for units or satellite hardware, to be assembled in the satellite, and execution of relevant acceptance test plan; Design, development and coding of application SW relevant to mission requirements and accomplishment of test plan to validate and accept the flight on board software; Integration between SW and real HW with validation test campaign Definition of GSE both for satellite and for subsystems, EGSE for performance verification and MGSE for handling, transportation and environmental tests; issuing of relevant specifications and consequent manufacturing and/or purchase; Test plan definition and issue of procedures for test and integration, for on board subsystems for which is needed a dedicated acceptance test program, execution of relevant performance acceptance test campaign; Issuing of satellite operational requirements handbook for launch campaign, orbit acquisition and operating life; Definition of satellite ground integration and test plan, definition of in orbit test plan and issue of the relevant detailed procedures. Solar cells integration on the relevant panels, inter-connection, testing and performance (flash test) verification.

24 ISSUE : 02 PAGE : 24/ Assembly, Integration and Ground Test Activities After the acceptance and delivery of all units and parts, the satellite will be integrated and submitted to a test program aimed to demonstrate, if necessary with support of specific analyses, the achievement of specified performances and the capability to survive and operate in the different environments of launch, transfer orbit and final operative orbit. The authorization to execution of each single step of ground test program is released after the demonstration that: all units and parts are qualified, the flight models of them have been accepted, the integration and test tools are adequate and available, the detailed integration and test procedure are ready and validated. This authorization is formally released by the Test Readiness Review (TRR) In Orbit Acceptance The satellite, after the acquisition of final operative orbital position, will be submitted to a dedicated test program (Commissioning Phase) in order to verify the proper operating modes compared with the ground test results, and to verify the communication performances compared with the specified requirements.

25 ISSUE : 02 PAGE : 25/ Model Philosophy Different approach for the model philosophy will be defined at the different project levels: system, module (payload and platform), subsystem and unit System and Platform Model Philosophy For what concern the platform and the system level (i.e., the complete satellite) it is proposed a single Proto Flight approach at system level, with the following considerations: The functional Satellite performances will be validated using a dedicated End to End simulator (purely SW) plus an Avionics Test Bench where representative HW will be included in the loop. This HW will be composed of breadboards and Off the Shelf component functionally representative of flight HW The Satellite thermo-structural performances and the compliance with the relevant requirements will be evaluated by analysis. The Proto Flight Model will be the final product after integration and it is the model that will be launched. Since a single complete Satellite model is foreseen, It will be subject to a complete proto-flight test campaign in order to confirm the functional validation performed on Simulators and the thermo-structural performances evaluated by analysis Payload Model Philosophy The Payload model philosophy is defined in [RD 26] Units and Subsystems Model Philosophy The model philosophy for units and subsystems will be different for recurring and non-recurring items. As a general rule, a Proto Flight approach will be used for the recurring parts. For what concerns the non-recurring items defined in section the following approach is proposed. FEEP One FEEP development model is foreseen along the qualification process, before the flight model. The proposed model philosophy is in [RD 19]. Spin Sensor Two models shall be foreseen along the qualification process: An Engineering Qualification Model (EQM), which shall be submitted to a complete qualification test campaign to assess the design and the technological solutions A Flight Model (FM), which shall be submitted to flight conditions test campaign before installation on the satellite.

26 ISSUE : 02 PAGE : 26/34 5. IMPLEMENTATION AND RELATED PLANS 5.1 SYSTEM ENGINEERING TASKS DESCRIPTION Work Packages The complete Work Breakdown Structure will be provided in the Implementation Proposal. 5.2 RELATED PLANS Programmatic Plans The following programmatic plans are envisaged (TBC): Sub-products engineering plans; Industrial procurement plan; Risk management plan; COTS plan Verification Plans The subject of the verification process is the GG satellite and its components. The complete satellite validation can be reached through tests, analysis, reviews of design inspections, performed at different levels and in different project phases. Figure shows the relation between the system engineering tasks and the verification activities. The AIV/AIT campaign is to demonstrate that: the GG design is qualified at the environmental condition; the overall GG satellite (including tools, procedures and resources) is able to fulfill mission requirements, being free from material and workmanship defects; the Final Model is delivered in due time. Furthermore also the cost target has to be accomplished in the AIV philosophy. Consequently, following the system architecture, different levels of verification are defined: Level 1: System; Satellite completely integrated Level 2: Module, that is Platform Module Payload Module Level 3: Subsystem Level 4: Equipment/Item.

27 ISSUE : 02 PAGE : 27/34 Figure 5.2-1: Verification logic and links

28 ISSUE : 02 PAGE : 28/ System AIV Plan At platform and system level the PFM will be subjected to a complete proto flight test campaign, including thermal testing, mechanical testing and electromagnetic compatibility. Figure provides a preliminary flow of the AIT plan according to the above philosophy. In the above scheme different colours are used to mark different responsible entities for each task: Green stands for a task under Industrial Prime responsibility (TAS-I Turin) Gold stands for an item/subsystem provided by an external subcontractor, where the Prime has anyway the procurement responsibility Blue stands for the payload and its components that is under TAS-I Milano responsibility, where TAS-I Turin have anyway the procurement responsibility as industrial prime Phase E is identified in a different colour since will be probably subjected to a different contract. GG Structure Delivery Harness I&T Propulsion I&T OBDH I&T PSS I&T AOCS I&T FEEP I&T GG Payload Delivery P/L & P/T I&T Integrated System Test 1 (with SVT 1) Conducted EMC S/L Sensors Alignment Measurements S/L Finalisation Physiscal Properties (MoI, CoG, mass) TV/TB Acceptance Test Sine Vibration Acoustic Test Separation Shock Alignments & Mechanisms Ver. Radiated EMC Integrated System Test 2 (with SVT 2) Propulsion Final Check GG ready for launch campaign: shipment to Launch Site Launch Campaign Subco Task TAS-I MI Task TAS-I TO Task Phase E Launch with VEGA carrier Figure 5.2-2: Development Plan at Satellite level

29 ISSUE : 02 PAGE : 29/ Payload AIV Plan The P/L AIV Plan is described in [RD 26] Subsystem/unit AIV Plan At Equipment and Subsystem levels the verification approach is defined as function of the single unit/subsystem TRL. The general approach is to have a complete qualification test campaign and consequently a qualification approach on the new items (see section 3.4.1) and to perform a reduced acceptance campaign on recurring units. The definition status is provided in the following references: FEEP: [RD 19] Spin Sensor: [RD 21] Other Platform units/subsystems: [RD 27] Engineering Discipline Plans As part of the GG project the following Engineering Discipline plans are envisaged (TBC): Microgravity Control Plan Electromagnetic Compatibility Plan Radio Frequency Plan Alignment Requirements and Control Plan System Performance Simulations Plan Software Development Plan Cleanliness and Contamination Control Plan Operations Plans As part of the GG project the following operations plans are envisaged (TBC): Launch site operations and logistics plan System commissioning and operation support plan.

30 ISSUE : 02 PAGE : 30/34 6. SYSTEM ENGINEERING FOR THE FOLLOWING PHASES 6.1 GG MASTER SCHEDULE The current GG master schedule is reported in Figure It includes phases B, C/D, E, F until the end of mission and the long term data archiving. The Ground Segment schedule is included with the following baseline: 2 years of mission (including commissioning) 1 year of long term data archiving.

31 ISSUE : 02 PAGE : 31/34 Figure 6.1-1: GG Master Schedule

32 ISSUE : 02 PAGE : 32/ GG KEY MILESTONES The main milestones of the project until launch are shown in Table 6.2-1, starting from the Kick Off of Phase B. This is a preliminary schedule used for the purposes of the preliminary ROM cost estimation. For both the payload and the platform, no criticalities have been reported and the proposed planning is considered achievable. R e v i e w s GS Model Key Events Phase B Kick-Off Preliminary Design Review Phase C/D Kick-Off Critical Design Review Test Readness Review Final Acceptance Review Launch Readness Review Launch Ground Segment Preliminary Design Review Ground Segment Critical Design Review Ground Segment Operations Qualification Review Main Goals Date from T0 T0 T0+9m T0+9m T0+21m T0+32m T0+45m T0+48m T0+48m T0+9m T0+22m T0+40m ATB Availability for GG ATB ATB Ready for SW Test ATB Test Completion FM/PFM Equipment Procurement Start Results of development models availability GSE for system activities availability FM/PFM Equipment Procurement Completion FM Flight PGB Availability at System Level S/L Ready for Environmental Test S/L Ready for Launch Campaign S/L Ready for Launch Table 6.2-1: GG Key Events T0+24m T0+27m T0+48m T0+21m T0+30m T0+30m T0+32m T0+35m T0+39m T0+45m T0+48m

33 ISSUE : 02 PAGE : 33/34 7. ACRONYMS AD AOCS ASI CCSDS CNES CPE DFACS DoD E2E ECE ECSS EP ESA FEM FOS G/S GG GGG HK INFN IORF ISV LEOP LL MLI MRD OBCP P/L PA PCB PPRF QL RD SD SPRF STS S/C S/S SEL SEU SPF STB SVF TBC Applicable Document Attitude and Control Subsystem Agenzia Spaziale Italiana Consultative Committee for Space Data Systems Centre National d Etudes Spatiales Control and Processing Electronics Drag Free Attitude and Control Subsystem Depth of Discharge End To End Simulator Experiment Control Electronics European Cooperation for Space Standardisation Equivalence Principle European Space Agency Finite Element Model Factor of Safety Ground Station Galileo Galilei (satellite) Galileo Galilei Ground experiment Housekeeping Istituto Nazionale di Fisica Nucleare Inertial Orbit Reference Frame Independent Software Validation Launch and Early Orbit Phase Limit Loads Multi Layer Insulation Mission Requirement Document Onboard Control Procedure Payload Product Assurance Pico Gravity Box Payload Physical Reference Frame Qualification Loads Reference Document Standard Document Satellite Physical Reference Frame System Technical Specification Spacecraft Subsystem Single Event Latch-Up Single Event Upset Single Point Failure Software Test Bed Software Validation Facility To Be Controlled

34 ISSUE : 02 PAGE : 34/34 TBD TC TM TRL To Be Defined Telecommand Telemetry Technology Readiness Level END OF DOCUMENT