Safety Design for Space Systems (eBook)

Front Cover 1
Safety Design for Space Systems 4
Copyright Page 5
Contents 6
Preface 24
Introduction 26
About the Editors 28
About the Contributors 32
Chapter 1: Introduction to Space Safety 70
1.1 Nasa and Safety 71
1.2 Definition of Safety and Risk 72
1.3 Managing Safety and Risk 72
1.4 The Book 74
References 74
Chapter 2: The Space Environment: Natural and Induced 76
2.1 The Atmosphere 77
2.1.1 Composition 77
2.1.2 Atomic Oxygen 82
2.1.3 The Ionosphere 84
2.2 Orbital Debris and Meteoroids 87
2.2.1 Orbital Debris 87
2.2.2 Meteoroids 95
2.3 Microgravity 100
2.3.1 Microgravity Defined 100
2.3.2 Methods of Attainment 103
2.3.3 Effects on Biological Processes and Astronaut Health 109
2.3.4 Unique Aspects of Travel to the Moon and Planetary Bodies 110
Recommended Reading 110
2.4 Acoutics 112
2.4.1 Acoustics Safety Issues 112
2.4.2 Acoustic Requirements 112
2.4.3 Compliance and Verification 119
2.4.4 Conclusions and Recommendations 120
Recommended Reading 120
2.5 Radiation 121
2.5.1 Ionizing Radiation 121
2.5.2 Radio Frequency Radiation 136
Recommended Reading 140
2.6 Natural and Induced Thermal Environments 141
2.6.1 Introduction to the Thermal Environment 141
2.6.2 Spacecraft Heat Transfer Considerations 141
2.6.3 The Natural Thermal Environment 142
2.6.4 The Induced Thermal Environment 149
2.6.5 Other Lunar and Planetary Environment Considerations 154
2.7 Combined Environmental Effects 155
2.7.1 Introduction to Environmental Effects 155
2.7.2 Combined Environments 156
2.7.3 Combined Effects 157
2.7.4 Ground Testing for Space Simulation 161
References 163
Chapter 3: Overview of Bioastronautics 174
3.1 Space Physiology 175
3.1.1 Muscular System 175
3.1.2 Skeletal System 176
3.1.3 Cardiovascular and Respiratory Systems 177
3.1.4 Neurovestibular System 179
3.1.5 Radiation 180
3.1.6 Nutrition 181
3.1.7 Immune System 182
3.1.8 Extravehicular Activity 183
3.2 Short and Long Duration Mission Effects 184
3.2.1 Muscular System 184
3.2.2 Skeletal System 185
3.2.3 Cardiovascular and Respiratory Systems 186
3.2.4 Neurovestibular System 188
3.2.5 Radiation 189
3.2.6 Nutrition 190
3.2.7 Immune System 190
3.2.8 Extravehicular Activity 191
3.3 Health Maintenance 192
3.3.1 Preflight Preparation 192
3.3.2 In-Flight Measures 195
3.3.3 In-Flight Medical Monitoring 208
3.3.4 Post-Flight Recovery 211
3.4 Crew Survival 212
3.4.1 Overview of Health Threats in Spaceflight 212
3.4.2 Early Work 213
3.4.3 Crew Survival on the Launch Pad, at Launch, and During Ascent 214
3.4.4 On-Orbit Safe Haven and Crew Transfer 219
3.4.5 Entry, Landing, and Post-Landing 219
3.5 Conclusion 221
Acknowledgment 221
References 222
Chapter 4: Basic Principles of Space Safety 232
4.1 The Cause of Accidents 232
4.2 Principles and Methods 234
4.2.1 Hazard Elimination and Limitation 234
4.2.2 Barriers and Interlocks 235
4.2.3 Fail-Safe Design 236
4.2.4 Failure and Risk Minimization 236
4.2.5 Monitoring, Recovery, and Escape 238
4.2.6 Crew Survival Systems 238
4.3 The Safety Review Process 239
4.3.1 Safety Requirements 239
4.3.2 The Safety Panels 240
4.3.3 The Safety Reviews 240
4.3.4 Nonconformances 242
References 243
Chapter 5: Human Rating Concepts 244
5.1 Human Rating Defined 244
5.1.1 Human Rated Systems 244
5.1.2 The NASA Human Rating and Process 245
5.1.3 The Human Rating Plan 246
5.1.4 The NASA Human Rating Certification Process 247
5.1.5 Human Rating in Commercial Human Spaceflight 247
5.2 Human Rating Requirements and Approaches 248
5.2.1 Key Human Rating Technical Requirements 248
5.2.2 Programmatic Requirements 251
5.2.3 Test Requirements 252
5.2.4 Data Requirements 253
Reference 253
Chapter 6: Life Support Systems Safety 254
6.1 Atmospheric Conditioning and Control 257
6.1.1 Monitoring Is the Key to Control 257
6.1.2 Atmospheric Conditioning 259
6.1.3 Carbon Dioxide Removal 265
6.2 Trace Contaminant Control 267
6.2.1 Of Tight Buildings and Spacecraft Cabins 267
6.2.2 Trace Contaminant Control Methodology 270
6.2.3 Trace Contaminant Control Design Considerations 278
6.3 Assessment of Water Quality in the Spacecraft Environment: Mitigating Health and Safety Concerns 280
6.3.1 Scope of Water Resources Relevant to Spaceflight 280
6.3.2 Spacecraft Water Quality and the Risk Assessment Paradigm 281
6.3.3 Water Quality Monitoring 286
6.3.4 Conclusion and Future Directions 289
6.4 Waste Management 289
6.5 Summary of Life Support Systems 290
References 291
Chapter 7: Emergency Systems 294
7.1 Space Rescue 294
7.1.1 Legal and Diplomatic Basis 295
7.1.2 The Need for Rescue Capability 295
7.1.3 Rescue Modes and Probabilities 298
7.1.4 Hazards in the Different Phases of Flight 300
7.1.5 Historic Distribution of Failures 301
7.1.6 Historic Rescue Systems 302
7.1.7 Space Rescue Is Primarily Self Rescue 312
7.1.8 Limitations of Ground Based Rescue 316
7.1.9 The Crew Return Vehicle as a Study in Space Rescue 318
7.1.10 Safe Haven 324
7.1.11 Conclusions 325
7.2 Personal Protective Equipment 325
7.2.1 Purpose of Personal Protective Equipment 325
7.2.2 Types of Personal Protective Equipment 326
References 334
Chapter 8: Collision Avoidance Systems 336
8.1 Docking Systems and Operations 337
8.1.1 Docking Systems as a Means for Spacecraft Orbital Mating 337
8.1.2 Design Approaches Ensuring Docking Safety and Reliability 339
8.1.3 Design Features Ensuring the Safety and Reliability of Russian Docking Systems 344
8.1.4 Analyses and Tests Performed for Verification of Safety and Reliability of Russian Docking Systems 347
Acknowledgment 349
8.2 Descent and Landing Systems 349
8.2.1 Parachute Systems 350
8.2.2 Known Parachute Anomalies and Lessons Learned 365
Acknowledgment 368
References 368
Chapter 9: Robotic Systems Safety 370
9.1 Generic Robotic Systems 370
9.1.1 Controller and Operator Interface 371
9.1.2 Arms and Joints 371
9.1.3 Drive System 372
9.1.4 Sensors 372
9.1.5 End Effector 372
9.2 Space Robotics Overview 372
9.3 Identification of Hazards and Their Causes 374
9.3.1 Electrical and Electromechanical Malfunctions 376
9.3.2 Mechanical and Structural Failures 376
9.3.3 Failure in the Control Path 376
9.3.4 Operator Error 376
9.3.5 Other Hazards 376
9.4 Hazard Mitigation in Design 377
9.4.1 Electrical and Mechanical Design and Redundancy 377
9.4.2 Operator Error 377
9.4.3 System Health Checks 377
9.4.4 Emergency Motion Arrest 378
9.4.5 Proximity Operations 378
9.4.6 Built in Test 379
9.4.7 Safety Algorithms 379
9.5 Hazard Mitigation Through Training 379
9.6 Hazard Mitigation for Operations 381
9.7 Case Study: Understanding Canadarm2 and Space Safety 382
9.7.1 The Canadarm2 382
9.7.2 Cameras 382
9.7.3 Force Moment Sensor 383
9.7.4 Training 384
9.7.5 Hazard Concerns and Associated Hazard Mitigation 385
9.8 Summary 386
References 387
Chapter 10: Meteoroid and Debris Protection 388
10.1 Risk Control Measures 388
10.1.1 Maneuvering 388
10.1.2 Shielding 393
10.2 Emergency Repair Considerations for Spacecraft Pressure Wall Damage 401
10.2.1 Balanced Mitigation of Program Risks 401
10.2.2 Leak Location System and Operational Design Considerations 406
10.2.3 Ability to Access the Damaged Area 406
10.2.4 Kit Design and Certification Considerations (1 is too many 100 are not enough)407
10.2.5 Recertification of the Repaired Pressure Compartment for Use by the Crew 407
References 408
Chapter 11: Noise Control Design 410
11.1 Introduction 410
11.2 Noise Control Plan 410
11.2.1 Noise Control Strategy 411
11.2.2 Acoustic Analysis 413
11.2.3 Testing and Verification 413
11.3 Noise Control Design Applications 414
11.3.1 Noise Control at the Source 415
11.3.2 Path Noise Control 417
11.3.3 Noise Control in the Receiving Space 422
11.3.4 Post-Design Noise Mitigation 424
11.4 Conclusions and Recommendations 424
Recommended reading 425
References 425
Chapter 12: Materials Safety 428
12.1 Toxic Offgassing 429
12.1.1 Materials Offgassing Controls 430
12.1.2 Materials Testing 431
12.1.3 Spacecraft Module Testing 432
12.2 Stress-Corrosion Cracking 432
12.2.1 What Is Stress-Corrosion Cracking? 433
12.2.2 Prevention of Stress-Corrosion Cracking 433
12.2.3 Testing Materials for Stress-Corrosion Cracking 435
12.2.4 Design for Stress-Corrosion Cracking 437
12.2.5 Requirements for Spacecraft Hardware 438
12.2.6 Stress-Corrosion Cracking in Propulsion Systems 440
12.3 Conclusions 442
References 442
Chapter 13: Oxygen Systems Safety 444
13.1 Oxygen Pressure System Design 444
13.1.1 Introduction 444
13.1.2 Design Approach 446
13.1.3 Oxygen Compatibility Assessment Process 455
13.2 Oxygen Generators 461
13.2.1 Electrochemical Systems for Oxygen Production 461
13.2.2 Solid Fuel Oxygen Generators (Oxygen Candles) 467
References 470
Chapter 14: Avionics Safety 472
14.1 Introduction to Avionics Safety 472
14.2 Electrical Grounding and Electrical Bonding 473
14.2.1 Defining Characteristics of an Electrical Ground Connection 474
14.2.2 Control of Electric Current 475
14.2.3 Electrical Grounds Can Be Signal Return Paths 475
14.2.4 Where and How Electrical Grounds Should Be Connected 475
14.2.5 Defining Characteristics of an Electrical Bond 477
14.2.6 Types of Electrical Bonds 477
14.2.7 Electrical Bond Considerations for Dissimilar Metals 478
14.2.8 Electrical Ground and Bond Connections for Shields 479
Recommended Reading 479
14.3 Safety Critical Computer Control 480
14.3.1 Partial Computer Control 481
14.3.2 Total Computer Control: Fail Safe 482
14.4 Circuit Protection: Fusing 483
14.4.1 Circuit Protection Methods 483
14.4.2 Circuit Protectors 485
14.4.3 Design Guidance 485
14.5 Electrostatic Discharge Control 486
14.5.1 Fundamentals 487
14.5.2 Various Levels of Electrostatic Discharge Concern 489
Recommended Reading 495
14.6 Arc Tracking 497
14.6.1 A New Failure Mode 497
14.6.2 Characteristics of Arc Tracking 500
14.6.3 Likelihood of an Arc Tracking Event 501
14.6.4 Prevention of Arc Tracking 501
14.6.5 Verification of Protection and Management of Hazards 502
14.6.6 Summary 502
14.7 Corona Control in High Voltage Systems 503
14.7.1 Associated Environments 503
14.7.2 Design Criteria 504
14.7.3 Verification and Testing 505
Recommended Reading 506
14.8 Extravehicular Activity Considerations 506
14.8.1 Displays and Indicators Used in Space 507
14.8.2 Mating and Demating of Powered Connectors 507
14.8.3 Single Strand Melting Points 508
14.8.4 Battery Removal and Installation 510
14.8.5 Computer or Operational Control of Inhibits 511
14.9 Spacecraft electromagnetic interference and electromagnetic compatibility control 511
14.9.1 Electromagnetic Compatibility Needs for Space Applications 512
14.9.2 Basic Electromagnetic Compatibility Interactions and a Safety Margin 513
14.9.3 Mission Driven Electromagnetic Interference Design: The Case for Grounding 514
14.9.4 Electromagnetic Compatibility Program for Spacecraft 515
14.10 Design and Testing of Safety Critical Circuits 519
14.10.1 Safety Critical Circuits: Conducted Mode 519
14.10.2 Safety Critical Circuits: Radiated Mode 525
14.11 Electrical Hazards 530
14.11.1 Introduction 530
14.11.2 Electrical Shock 530
14.11.3 Physiological Considerations 531
14.11.4 Electrical Hazard Classification 532
14.11.5 Leakage Current 533
14.11.6 Bioinstrumentation 533
14.11.7 Electrical Hazard Controls 534
14.11.8 Verification of Electrical Hazard Controls 537
14.11.9 Electrical Safety Design Considerations 537
14.12 Avionics Lessons Learned 538
14.12.1 Electronic Design 538
14.12.2 Physical Design 539
14.12.3 Materials and Sources 540
14.12.4 Damage Avoidance 541
14.12.5 System Aspects 541
References 542
Chapter 15: Software System Safety 544
15.1 Introduction 544
15.2 The Software Safety Problem 545
15.2.1 System Accidents 545
15.2.2 The Power and Limitations of Abstraction from Physical Design 546
15.2.3 Reliability Versus Safety for Software 548
15.2.4 Inadequate System Engineering 551
15.2.5 Characteristics of Embedded Software 553
15.3 Current Practice 555
15.3.1 System Safety 556
15.4 Best Practice 558
15.4.1 Management of Software-Intensive, Safety-Critical Projects 559
15.4.2 Basic System Safety Engineering Practices and Their Implications for Software Intensive Systems 560
15.4.3 Specifications 562
15.4.4 Requirements Analysis 563
15.4.5 Model-Based Software Engineering and Software Reuse 563
15.4.6 Software Architecture 565
15.4.7 Software Design 566
15.4.8 Design of Human-Computer Interaction 569
15.4.9 Software Reviews 570
15.4.10 Verification and Assurance 571
15.4.11 Operations 572
15.5 Summary 572
References 572
Chapter 16: Battery Safety 576
16.1 Introduction 576
16.2 General Design And Safety Guidelines 577
16.3 Battery Types 577
16.4 Battery Models 578
16.5 Hazard and Toxicity Categorization 578
16.6 Battery Chemistry 578
16.6.1 Alkaline Batteries 578
16.6.2 Lithium Batteries 581
16.6.3 Silver Zinc Batteries 592
16.6.4 Lead Acid Batteries 594
16.6.5 Nickel Cadmium Batteries 596
16.6.6 Nickel Metal Hydride Batteries 597
16.6.7 Nickel Hydrogen Batteries 602
16.6.8 Lithium-Ion Batteries 604
16.7 Storage, Transportation, and Handling 613
References 614
Chapter 17: Mechanical Systems Safety 618
17.1 Safety Factors 618
17.1.1 Types of Safety Factors 619
17.1.2 Safety Factors Typical of Human Rated Space Programs 620
17.1.3 Things That Influence the Choice of Safety Factors 620
17.2 Spacecraft Structures 620
17.2.1 Mechanical Requirements 621
17.2.2 Space Mission Environment and Mechanical Loads 623
17.2.3 Project Overview: Successive Designs and Iterative Verification of Structural Requirements 626
17.2.4 Analytical Evaluations 628
17.2.5 Structural Test Verification 628
17.2.6 Spacecraft Structural Model Philosophy 630
17.2.7 Materials and Processes 631
17.2.8 Manufacturing of Spacecraft Structures 633
Recommended Reading 635
17.3 Fracture Control 636
17.3.1 Basic Requirements 636
17.3.2 Implementation 636
17.3.3 Summary 637
17.4 Pressure Vessels, Lines, and Fittings 637
17.4.1 Pressure Vessels 637
17.4.2 Lines and Fittings 643
17.4.3 Space Pressure Systems Standards 644
17.4.4 Summary 644
17.5 Composite Overwrapped Pressure Vessels 645
17.5.1 The Composite Overwrapped Pressure Vessel System 645
17.5.2 Monolithic Metallic Pressure Vessel Failure Modes 646
17.5.3 Composite Overwrapped Pressure Vessel Failure Modes 647
17.5.4 Composite Overwrapped Pressure Vessel Impact Sensitivity 648
17.5.5 Summary 650
17.6 Structural Design of Glass and Ceramic Components for Space System Safety 650
17.6.1 Strength Characteristics of Glass and Ceramics 651
17.6.2 Defining Loads and Environments 655
17.6.3 Design Factors 657
17.6.4 Meeting Life Requirements with Glass and Ceramics 658
17.7 Safety Critical Mechanisms 660
17.7.1 Designing for Failure Tolerance 660
17.7.2 Design and Verification of Safety Critical Mechanisms 663
17.7.3 Reduced Failure Tolerance 671
17.7.4 Review of Safety Critical Mechanisms 673
References 674
Chapter 18: Containment of Hazardous Materials 676
18.1 Toxic Materials 679
18.1.1 Fundamentals of Toxicology 679
18.1.2 Toxicological Risks to Air Quality in Spacecraft 682
18.1.3 Risk Management Strategies 687
18.2 Biohazardous Materials 690
18.2.1 Microbiological Risks Associated with Spaceflight 690
18.2.2 Risk Mitigation Approaches 691
18.2.3 Major Spaceflight Specific Microbiological Risks 692
18.3 Shatterable Materials 700
18.3.1 Shatterable Materials in a Habitable Compartment 700
18.3.2 Program Implementation 700
18.3.3 Containment Concepts for Internal Equipment 702
18.3.4 Containment Concepts for Exterior Equipment 705
18.3.5 General Comments About Working with Shatterable Materials 707
18.4 Containment Design Approach 708
18.4.1 Fault Tolerance 708
18.4.2 Design for Minimum Risk 708
18.5 Containment Design Methods 709
18.5.1 Containment Environments 709
18.5.2 Design of Containment Systems 709
18.6 Safety Controls 712
18.6.1 Proper Design 712
18.6.2 Materials Selection 712
18.6.3 Materials Compatibility 712
18.6.4 Proper Workmanship 713
18.6.5 Proper Loading or Filling 713
18.6.6 Fracture Control 713
18.7 Safety Verifications 713
18.7.1 Strength Analysis 714
18.7.2 Qualification Tests 714
18.7.3 Acceptance Tests 715
18.7.4 Proof Tests 716
18.7.5 Qualification of Procedures 716
18.8 Conclusions 717
References 718
Chapter 19: Failure Tolerance Design 722
19.1 Safe 722
19.1.1 Order of Precedence 722
19.2 Hazard 724
19.2.1 Hazard Controls 724
19.2.2 Design to Tolerate Failures 725
19.3 Hazardous Functions 727
19.3.1 Must Not Work Hazardous Function 727
19.3.2 Must Work Hazardous Function 728
19.4 Design for Minimum Risk 728
19.5 Conclusions 729
References 729
Chapter 20: Propellant Systems Safety 730
20.1 Solid Propellant Propulsion Systems Safety 731
20.1.1 Solid Propellants 731
20.1.2 Solid Propellant Systems for Space Applications 733
20.1.3 Safety Hazards 733
20.1.4 Handling, Transport, and Storage 739
20.1.5 Inadvertent Ignition 740
20.1.6 Safe Ignition Systems Design 741
20.1.7 Conclusions 742
20.2 Liquid Propellant Propulsion Systems Safety 742
20.2.1 Planning 744
20.2.2 Containment Integrity 745
20.2.3 Thermal Control 746
20.2.4 Materials Compatibility 747
20.2.5 Contamination Control 747
20.2.6 Environmental Considerations 748
20.2.7 Engine and Thruster Firing Inhibits 748
20.2.8 Heightened Risk (Risk Creep) 749
20.2.9 Instrumentation and Telemetry Data 750
20.2.10 End to End Integrated Instrumentation, Controls, and Redundancy Verification 750
20.2.11 Qualification 750
20.2.12 Total Quality Management (ISO 9001 or Equivalent) 751
20.2.13 Preservicing Integrity Verification 751
20.2.14 Propellants Servicing 752
20.2.15 Conclusions 752
20.3 Hypergolic Propellants 752
20.3.1 Materials Compatibility 752
20.3.2 Material Degradation 753
20.3.3 Hypergolic Propellant Degradation 754
20.4 Propellant Fire 755
20.4.1 Hydrazine and Monomethylhydrazine Vapor 756
20.4.2 Liquid Hydrazine and Monomethylhydrazine 759
20.4.3 Hydrazine and Monomethylhydrazine Mists, Droplets, and Sprays 760
References 760
Chapter 21: Pyrotechnic Safety 764
21.1 Pyrotechnic Devices 764
21.1.1 Explosives 765
21.1.2 Initiators 765
21.2 Electroexplosive Devices 765
21.2.1 Safe Handling of Electroexplosive Devices 766
21.2.2 Designing for Safe Electroexplosive Device Operation 769
21.2.3 Pyrotechnic Safety of Mechanically Initiated Explosive Devices 771
References 773
Chapter 22: Extravehicular Activity Safety 774
22.1 Extravehicular Activity Environment 774
22.1.1 Definitions 775
22.1.2 Extravehicular Activity Space Suit 777
22.1.3 Sensory Degradation 779
22.1.4 Maneuvering and Weightlessness 779
22.1.5 Glove Restrictions 780
22.1.6 Crew Fatigue 780
22.1.7 Thermal Environment 780
22.1.8 Extravehicular Activity Tools 781
22.2 Suit Hazards 781
22.2.1 Inadvertent Contact Hazards 781
22.2.2 Area of Effect Hazards 784
22.3 Crew Hazards 785
22.3.1 Contamination of the Habitable Environment 785
22.3.2 Thermal Extremes 785
22.3.3 Lasers 787
22.3.4 Electrical Shock and Molten Metal 787
22.3.5 Entrapment 788
22.3.6 Emergency Ingress 788
22.3.7 Collision 789
22.3.8 Inadvertent Loss of Crew 790
22.4 Conclusions 791
References 791
Chapter 23: Emergency, Caution, and Warning System 794
23.1 System Overview 794
23.2 Historic Nasa Emergency, Caution, and Warning Systems 795
23.3 Emergency, Caution, and Warning System Measures 796
23.3.1 Event Classification Measures 796
23.3.2 Sensor Measures 797
23.3.3 Data System Measures 798
23.3.4 Annunciation Measures 799
23.4 Failure Isolation and Recovery 800
Reference 801
Chapter 24: Laser Safety 802
24.1 Background 802
24.1.1 Optical Spectrum 802
24.1.2 Biological Effects 803
24.2 Laser Characteristics 804
24.2.1 Laser Principles 804
24.2.2 Laser Types 806
24.3 Laser Standards 807
24.3.1 NASA Johnson Space Center Requirements 807
24.3.2 ANSI Standard Z136-1 808
24.3.3 Russian Standard 809
24.4 Lasers Used in Space 809
24.4.1 Radars 810
24.4.2 Illumination 810
24.4.3 Sensors 810
24.5 Design Considerations for Laser Safety 811
24.5.1 Ground Testing 811
24.5.2 Unique Space Environment 811
24.6 Conclusions 813
References 813
Chapter 25: Crew Training Safety: An Integrated Process 814
25.1 Training the Crew for Safety 815
25.1.1 Typical Training Flow 815
25.1.2 Principles of Safety Training for the Different Training Phases 821
25.1.3 Specific Safety Training for Different Equipment Categories 824
25.1.4 Safety Training for Different Operations Categories 830
25.2 Safety During Training 839
25.2.1 Overview 839
25.2.2 Training, Test, or Baseline Data Collection Model Versus Flight Model: Type, Fidelity, Source, Origin, and Category 840
25.2.3 Training Environments and Facilities 844
25.2.4 Training Models, Test Models, and Safety Requirements 850
25.2.5 Training Model, Test Model, and Baseline Data Collection Equipment Utilization Requirements 864
25.2.6 Qualification and Certification of Training Personnel 867
25.2.7 Training and Test Model Documentation 868
25.3 Training Development and Validation Process 872
25.3.1 The Training Development Process 875
25.3.2 The Training Review Process 876
25.3.3 The Role of Safety in the Training Development and Validation Processes 878
25.3.4 Feedback to the Safety Community from the Training Development and Validation Processes 881
25.4 Conclusions 884
References 884
Chapter 26: Safety Considerations for the Ground Environment 886
26.1 A Word about Ground Support Equipment 887
26.2 Documentation and Reviews 888
26.3 Roles and Responsibilities 888
26.4 Contingency Planning 888
26.5 Failure Tolerance 889
26.6 Training 889
26.7 Hazardous Operations 890
26.8 Tools 891
26.9 Human Factors 891
26.10 Biological Systems and Materials 892
26.11 Electrical 893
26.12 Radiation 893
26.13 Pressure Systems 894
26.14 Ordinance 894
26.15 Mechanical and Electromechanical Devices 895
26.16 Propellants 895
26.17 Cryogenics 895
26.18 Oxygen 895
26.19 Ground Handling 896
26.20 Software Safety 896
26.21 Summary 897
Chapter 27: Fire Safety 898
27.1 Characteristics of Fire in Space 899
27.1.1 Overview of Low Gravity Fire 899
27.1.2 Fuel and Oxidizer Supply and Flame Behavior 900
27.1.3 Fire Appearance and Signatures 901
27.1.4 Flame Ignition and Spread 905
27.1.5 Summary of Low Gravity Fire Characteristics 914
27.2 Design for Fire Prevention 916
27.2.1 Materials Flammability 916
27.2.2 Ignition Sources 921
27.3 Spacecraft Fire Detection 924
27.3.1 Prior Spacecraft Systems 924
27.3.2 Review of Low Gravity Smoke 927
27.3.3 Spacecraft Atmospheric Dust 928
27.3.4 Sensors for Fire Detection 929
27.4 Spacecraft Fire Suppression 933
27.4.1 Spacecraft Fire Suppression Methods 933
27.4.2 Considerations for Spacecraft Fire Suppression 936
References 946
Chapter 28: Safe Without Services Design 954
Chapter 29: Probabilistic Risk Assessment with Emphasis on Design 958
29.1 Basic Elements of Probabilistic Risk Assessment 958
29.1.1 Identification of Initiating Events 959
29.1.2 Application of Event Sequence Diagrams and Event Trees 960
29.1.3 Modeling of Pivotal Events 962
29.1.4 Linkage and Quantification of Accident Scenarios 963
29.2 Construction of a Probabilistic Risk Assessment for Design Evaluations 963
29.2.1 Uses of Probabilistic Risk Assessment 963
29.2.2 Reference Mission 965
29.3 Relative Risk Evaluations 967
29.3.1 Absolute Versus Relative Risk Assessments 968
29.3.2 Roles of Relative Risk Assessments in Design Evaluations 969
29.3.3 Quantitative Evaluations 971
29.4 Evaluations of the Relative Risks of Alternative Designs 973
29.4.1 Overview of Probabilistic Risk Assessment Models Developed 973
29.4.2 Relative Risk Comparisons of the Alternative Designs 974
References 980
Index 982