Miguel A. Aguirre Introduction to Space Systems Design and Synthesis ) Springer
Contents Foreword Acknowledgments v vii 1 Introduction 1 1.1. Aim of the book 2 1.2. Roles in the architecture definition process 5 1.3. The perspective during the system architecture definition phases 8 1.4. Design and implementation as a evolving process 10 1.5. Proj ect phases and proj ect reviews 13 1.6. What is a space system? 14 1.7. Terminology 15 1.8. Recommended supplementary reading 16 2 Space Disciplines 17 2.1. Space system engineering 18 2.1.1. Integration and control 19 2.1.2. Interfaces management 19 2.1.3. Requirements engineering 20 2.1.4. System analysis 21 2.1.5. Design and configuration definition 22 2.1.6. Verification 22 2.2. Space system architecting 23 2.2.1. The architect in the classical role 24 2.2.2. Architecture definition formalisms 25 2.3. Project management 27 2.4. Satellite engineering disciplines 27 2.4.1. Structure 28 2.4.2. Thermal control 29 2.4.3. Mechanisms 30 2.4.4. Attitude control 31 2.4.5. Propulsion 32 2.4.6. Electrical power 32 2.4.7. Data handling 33 2.4.8. Software 34 2.4.9. Communications 35 2.5. Instruments engineering 36 2.6. Engineering support disciplines 37 2.6.1. Manufacturing assembly, integration, verification, and testing engineering 37 2.6.2. Product assurance 40 ix
X Introduction to Space Systems 2.6.3. Satellite flight operations 41 2.6.4. Satellite data output processing 42 2.6.5. Cost engineering 43 2.7. The consumer: the scientist behind the mission 43 3 Requirements, Specifications, and Design 45 3.1. Levels of system decomposition 45 3.2. Specification and requirements types 48 3.2.1. Specification types 48 3.2.2. Requirements types 53 3.2.3. Requirements for technical specifications 55 3.3. Requirements engineering 55 3.4. Value engineering 58 3.4.1. The different values of requirements 59 3.4.2. System effectiveness metrics 60 3.5. Requirements and verifiability 62 4 Constraints and Design 65 4.1. Requirements versus constraints 65 4.2. The external environment of a space project 66 4.2.1. STEP analysis 66 4.2.2. Forecasting and scenario analysis 68 4.3. History of selected past space endeavors 69 4.3.1. Private versus public communications and Earth observation 69 4.3.2. Apollo 70 4.4. The programmatic framework as constraint 71 4.5. Types of projects by project aims 72 4.5.1. Capabilities demonstration 72 4.5.2. Technical demonstration 72 4.5.3. Advancement of science 73 4.5.4. Operational 74 4.6. Type of projects by projects criticality 75 4.7. Types of projects by project size 76 4.8. Cost 76 4.8.1. Top-down cost estimation 78 4.8.2. Bottom-up cost estimation 80 4.8.3. The risk of cost estimations 81 4.8.4. Single satellite versus multiple satellites cost 82 4.9. Risk constraints 82 4.9.1. Qualitative risk management 82 4.9.2. Quantitative risk management 85 4.9.3. Technical readiness and technical development 86 4.9.4. Developmental approach and model philosophy 88 4.10. Schedule constraints 91 4.11. Management trends as constraints 92
Contents xl 5 System Design as a Synchronic Process 95 5.1. Space system elements 96 5.2. System specification, system design, and system architect 98 5.3. Design against constraints 100 5.3.1. Cost 101 5.3.2. Risk 103 5.3.3. Schedule 104 5.4. Design against requirements 105 5.5. Tools for design 106 5.5.1. Analysis and design 106 5.5.2. Functional analysis and functional decomposition 108 5.5.3. Trade-offs and design 109 5.5.4. Budget allocation engineering 113 5.5.5. Concurrent engineering 115 5.5.6. Dependability 116 5.6. Design and mission performances 119 5.6.1. Mission effectiveness metrics 121 5.6.2. Effectiveness metrics limitations 122 5.6.3. Safety margins, mistakes, and errors 124 5.7. Nonnumerical support to decision making 126 5.8. Numerical support to decision making 127 5.8.1. Deterministic approaches 127 5.8.2. Nonprobabilistic numerical approaches in situation of uncertainty 127 5.8.3. Probabilistic approaches 128 6 System Definition as a Diachronic Process 129 6.1. The system definition process as recurrent and linear 129 6.2. System definition as a recursive process 130 6.3. System definition as a linear process 133 6.3.1. Phase 0 134 6.3.2. Phase A 135 6.3.3. Phase Bl 137 6.4. Mission milestones and reviews 139 6.4.1. Review procedure 141 6.4.2. Reviews during the mission definition stages 141 6.5. Parallel developments 143 6.5.1. Technical maturity improvement 144 6.5.2. Scientific understanding advancement 144 7 Introduction to the Design Domains 147 7.1. Design interactions and design domains 147 7.1.1. The observables and instruments domain 149 7.1.2. The orbit and attitude domain 151 7.1.3. The satellite configuration domain 152 7.1.4. The satellite operations data flow domain 154 7.1.5. The instrument output data flow domain 156
Introduction to Space Systems 7.2. The astronomical observatory missions as an example of space system design 157 7.2.1. Mission descriptions 158 7.2.2. Comparison ofthe missions 163 7.2.3. Observatory mission highest-level design interactions 169 7.3. Multi-satellite design aspects 171 7.3.1. Data quantity and quality versus number of satellites 171 7.3.2. Mission life versus number of satellites 174 7.4. Systems of systems 175 The Observables and Instruments Domain 177 8.1. Observables and instrument selection 178 8.2. Elements and components involved in the observables and instruments domain 180 8.2.1. Passive optical 181 8.2.2. Active optical 185 8.2.3. Passive microwave 187 8.2.4. Active microwave 188 8.2.5. In situ instruments 192 8.2.6. Communication payloads 193 8.3. Instruments examples 193 8.3.1. Aeolus 193 8.3.2. JWST 195 8.3.3. Sentinel-3 196 8.3.4. Megha-Tropiques 198 8.3.5. Ulysses 200 8.4. Observational needs as design drivers 201 8.4.1. Observation frequency and atmosphere 201 8.4.2. Data quality 203 8.4.3. Image distortion 206 8.4.4. Data quantity 207 8.4.5. Systematic versus interactive observation 209 8.4.6. Responsiveness, acquisition delay, and latency 211 8.4.7. Observations and rotation of the line of sight 212 8.4.8. Instrument interfaces 213 8.5. End-to-end performance as design driver 214 8.6. Allocation of functions 217 8.6.1. Scanning 217 8.6.2. Internal and external calibration 220 8.6.3. Solid aperture versus deployable versus synthetic aperture 221 8.6.4. Resolution versus altitude 221 8.7. Allocation of budgets 223 8.7.1. Radiometric quality 223 8.7.2. MTF 223 8.7.3. The end-to-end performance 224
Contents xiii 9 The Orbit and Attitude Domain 227 9.1. Elements and components involved in the domain 229 9.1.1. Launchers 229 9.1.2. Orbit determination and correction 230 9.1.3. Attitude determination and control 234 9.2. The space environment as orbit and attitude design driver 237 9.2.1. Gravity field 237 9.2.2. Earth's magnetic field 238 9.2.3. Neutral atmosphere 239 9.2.4. Solar radiation 240 9.2.5. Ionosphere radiation 241 9.2.6. The space environment outside the Earth 242 9.3. Attitude and attitude types 243 9.3.1. Uncontrolled satellite attitude 245 9.3.2. Gravity-gradient attitude control 245 9.3.3. Stabilized by rotation attitude control 246 9.3.4. Dual spin and momentum bias attitude control 247 9.3.5. Inertially stabilized attitude control 248 9.4. Orbits and orbit types 249 9.4.1. Low Earth Orbit (LEO) 250 9.4.2. LEO Sun-synchronous orbit 252 9.4.3. MEO 255 9.4.4. Geosynchronous and geostationary orbits 257 9.4.5. Longer period Earth orbit 259 9.4.6. Lagrangian points 259 9.4.7. Interplanetary orbits 261 9.4.8. Orbits around other planets 261 9.5. Mission phases and modes and satellite attitude 262 9.6. Orbit and attitude examples 264 9.6.1. Sentinel-3 264 9.6.2. Ulysses 266 9.6.3. Iridium 268 9.6.4. Pleiades 270 9.7. Geometry around the satellite 272 9.7.1. Nadir pointing 273 9.7.2. Rotating satellites 281 9.7.3. Inertial satellites 282 9.8. Pointing control, pointing perturbations, and pointing corrections... 283 9.8.1. Satellite and instruments pointing and pointing perturbations 284 9.8.2. Pointing control, pointing perturbing torques, image acquisition, and frequency ranges 286 9.8.3. Pointing error types 289 9.9. Allocation offunctions 291 9.9.1. Orbit selection 291 9.9.2. Attitude selection 293 9.9.3. Coverage and revisit 293
tjv Introduction to Space System. 9.10. Allocation of budgets 297 9.10.1. Satellite location 297 9.10.2. Instruments line of sight pointing and recovery 298 9.10.3. Pointing stability realization and recovery 300 9.10.4. Geo-locating 301 9.10.5. Co-registration 303 9.10.6. Repointing agility requirements 303 9.10.7. Delta V and fuel 304 9.10.8. Mechanical perturbations 306 9.11. Implementation and maintenance of constellations 307 10 The Satellite Configuration Domain 311 10.1. Components involved in the domain 313 10.1.1. Structure 313 10.1.2. Thermal 315 10.1.3. Mechanisms 317 10.1.4. Solar array 318 10.2. The external environment as configuration driver 320 10.2.1. Launcher 320 10.2.2. Load environment 324 10.2.3. Thermal radiation environment: Sun, Earth and deep space 329 10.2.4. Space environment generated external forces and torques 330 10.2.5. Electromagnetic radiation environment 331 10.2.6. Other effects of the external environment 333 10.3. Configuration examples 334 10.3.1. GOCE 334 10.3.2. Ulysses 337 10.3.3. JWST 337 10.3.4. Iridium 340 10.4. The geometry around the satellite and the configuration 342 10.4.1. Nadir-pointed satellites 342 10.4.2. Spinning satellites 350 10.4.3. Inertially pointed satellites 354 10.4.4. Agile satellites 355 10.5. Allocation of functions 356 10.5.1. Primary structural shape 356 10.5.2. Deployable structure and mechanisms: Fixed versus deployable 359 10.5.3. Standard platform versus dedicated platform 362 10.5.4. Passive versus active thermal control 365 10.5.5. Pointing by the instrument versus pointing by the satellite 365 10.6. Allocation of performances 366 10.6.1. Mass budget 366 10.6.2. Heat budget 369
Contents xv 10.6.3. Power production budget 370 10.6.4. Alignment budgets 371 10.6.5. Volume budget 372 11 The Operational Data Flow Domain 373 11.1. In-orbit components involved in the domain 374 11.1.1. Power 375 11.1.2. Satellite data handling 376 11.1.3. Telemetry and telecommand data communications 378 11.2. On-ground components involved in the domain 381 11.2.1. Operational ground stations and data-relay satellites 381 U.2.2. Mission operations control centers 382 11.3. Mission phases 383 11.3.1. Launch and early operations 3 84 11.3.2. Commissioning ofthe satellite 3 84 11.3.3. Nominal operation 384 11.3.4. Safe mode and other dormant modes 385 11.3.5. Nominal orbit correction maneuvers 385 11.3.6. Decommissioning and disposal 385 11.4. Examples of data handling architectures 385 11.4.1. Cluster 385 11.4.2. Rosetta 389 11.4.3. Sentinel-3 394 11.4.4. SSTL-DMC 395 11.5. Allocation of functions 398 11.5.1. Systematic versus interactive operations 398 11.5.2. Autonomy versus ground intervention 400 11.5.3. Fast versus slow commanding 402 11.5.4. Number and location of operational ground station 405 11.5.5. Orbit determination and control functions allocation 406 11.6. Allocation of performances 407 11.6.1. Power budget 407 11.6.2. Communications link budgets 409 11.6.3. Computer load budget 412 U.6.4. Operational on-board storage 412 11.6.5. Data acquisition delay budget 413 11.6.6. Level of service and availability budget 414 12 The Instrument Output Data Flow Domain 415 12.1. In-orbit components involved in the domain 415 12.1.1. Instrument output data handling 415 12.1.2. Instrument data output downlink 417 12.2. On-ground components involved in the domain 418 12.2.1. Instrument downlink ground stations and data relay satellites 419 12.2.2. Payload data segment 420
[Vj Introduction to Space Systems 12.3. Examples of architectures 423 12.3.1. Cluster 423 12.3.2. Rosetta 424 12.3.3. Sentinel-3 425 12.3.4. NOAA-POESS 428 12.4. Allocation of functions 431 12.4.1. Large versus small amount of data 431 12.4.2. Short versus long data latency 433 12.4.3. Existing, to-be-acquired and subscribed products 435 12.4.4. In-orbit versus on-ground processing 437 12.4.5. Number and location of ground stations 438 12.4.6. Centralized versus decentralized processing 441 12.4.7. Science operations separated or as part of overall operations 442 12.5. Allocation of performances 443 12.5.1. On-board storage memory budget 443 12.5.2. Data downlink budget 443 12.5.3. Data latency budget 445 13 Space Missions Cost and Alternative Design Approaches 451 13.1. The space mission and cost 451 13.2. Methods of cost reduction 453 13.2.1. Proper architectural definition 453 13.2.2. Hardware optimization 455 13.2.3. Organization optimization 456 13.2.4. Organization and hardware centered: small simple satellites within a lean project organization 457 13.3. Projects without the duality sponsor/consumer 461 13.4. Projects with a very low level of novelty, projects without customer 462 13.5. Cost engineering as art and science 462 Index 465