Preface...xxiii Introduction...xxv About the Editors...xxvii About the Contributors... xxxi

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2 Contents Preface...xxiii Introduction...xxv About the Editors...xxvii About the Contributors... xxxi CHAPTER 1 Introduction to Space Safety NASA and Safety Definition of Safety and Risk Managing Safety and Risk The Book... 5 References... 5 CHAPTER 2 The Space Environment: Natural and Induced The Atmosphere Composition Atomic Oxygen The Ionosphere Orbital Debris and Meteoroids Orbital Debris Meteoroids Microgravity Microgravity Defined Methods of Attainment Effects on Biological Processes and Astronaut Health Unique Aspects of Travel to the Moon and Planetary Bodies Recommended Reading Acoustics Acoustics Safety Issues Acoustic Requirements Compliance and Verification Conclusions and Recommendations Recommended Reading Radiation Ionizing Radiation Radio Frequency Radiation Recommended Reading v

3 vi Contents 2.6 Natural and Induced Thermal Environments Introduction to the Thermal Environment Spacecraft Heat Transfer Considerations The Natural Thermal Environment The Induced Thermal Environment Other Lunar and Planetary Environment Considerations Combined Environmental Effects Introduction to Environmental Effects Combined Environments Combined Effects Ground Testing for Space Simulation References CHAPTER 3 Overview of Bioastronautics Space Physiology Muscular System Skeletal System Cardiovascular and Respiratory Systems Neurovestibular System Radiation Nutrition Immune System Extravehicular Activity Short and Long Duration Mission Effects Muscular System Skeletal System Cardiovascular and Respiratory Systems Neurovestibular System Radiation Nutrition Immune System Extravehicular Activity Health Maintenance Preflight Preparation In-Flight Measures In-Flight Medical Monitoring Post-Flight Recovery Crew Survival Overview of Health Threats in Spaceflight Early Work...144

4 Contents vii Crew Survival on the Launch Pad, at Launch, and During Ascent On-Orbit Safe Haven and Crew Transfer Entry, Landing, and Post-Landing Conclusion Acknowledgment References CHAPTER 4 Basic Principles of Space Safety The Cause of Accidents Principles and Methods Hazard Elimination and Limitation Barriers and Interlocks Fail-Safe Design Failure and Risk Minimization Monitoring, Recovery, and Escape Crew Survival Systems The Safety Review Process Safety Requirements The Safety Panels The Safety Reviews Nonconformances References CHAPTER 5 Human Rating Concepts Human Rating Defined Human Rated Systems The NASA Human Rating and Process The Human Rating Plan The NASA Human Rating Certification Process Human Rating in Commercial Human Spaceflight Human Rating Requirements and Approaches Key Human Rating Technical Requirements Programmatic Requirements Test Requirements Data Requirements Reference CHAPTER 6 Life Support Systems Safety Atmospheric Conditioning and Control Monitoring Is the Key to Control...188

5 viii Contents Atmospheric Conditioning Carbon Dioxide Removal Trace Contaminant Control Of Tight Buildings and Spacecraft Cabins Trace Contaminant Control Methodology Trace Contaminant Control Design Considerations Assessment of Water Quality in the Spacecraft Environment: Mitigating Health and Safety Concerns Scope of Water Resources Relevant to Spaceflight Spacecraft Water Quality and the Risk Assessment Paradigm Water Quality Monitoring Conclusion and Future Directions Waste Management Summary of Life Support Systems References CHAPTER 7 Emergency Systems Space Rescue Legal and Diplomatic Basis The Need for Rescue Capability Rescue Modes and Probabilities Hazards in the Different Phases of Flight Historic Distribution of Failures Historic Rescue Systems Space Rescue Is Primarily Self Rescue Limitations of Ground Based Rescue The Crew Return Vehicle as a Study in Space Rescue Safe Haven Conclusions Personal Protective Equipment Purpose of Personal Protective Equipment Types of Personal Protective Equipment References CHAPTER 8 Collision Avoidance Systems Docking Systems and Operations Docking Systems as a Means for Spacecraft Orbital Mating...268

6 Contents ix Design Approaches Ensuring Docking Safety and Reliability Design Features Ensuring the Safety and Reliability of Russian Docking Systems Analyses and Tests Performed for Verification of Safety and Reliability of Russian Docking Systems Acknowledgment Descent and Landing Systems Parachute Systems Known Parachute Anomolies and Lessons Learned Acknowledgment References CHAPTER 9 Robotic Systems Safety Generic Robotic Systems Controller and Operator Interface Arms and Joints Drive System Sensors End Effector Space Robotics Overview Identification of Hazards and Their Causes Electrical and Electromechanical Malfunctions Mechanical and Structural Failures Failure in the Control Path Operator Error Other Hazards Hazard Mitigation in Design Electrical and Mechanical Design and Redundancy Operator Error System Health Checks Emergency Motion Arrest Proximity Operations Built in Test Safety Algorithms Hazard Mitigation Through Training Hazard Mitigation for Operations Case Study: Understanding Canadarm2 and Space Safety The Canadarm Cameras Force Moment Sensor...314

7 x Contents Training Hazard Concerns and Associated Hazard Mitigation Summary References CHAPTER 10 Meteoroid and Debris Protection Risk Control Measures Maneuvering Shielding Emergency Repair Considerations for Spacecraft Pressure Wall Damage Balanced Mitigation of Program Risks Leak Location System and Operational Design Considerations Ability to Access the Damaged Area Kit Design and Certification Considerations (1 is too many, 100 are not enough) Recertification of the Repaired Pressure Compartment for Use by the Crew References CHAPTER 11 Noise Control Design Introduction Noise Control Plan Noise Control Strategy Acoustic Analysis Testing and Verification Noise Control Design Applications Noise Control at the Source Path Noise Control Noise Control in the Receiving Space Post-Design Noise Mitigation Conclusions and Recommendations Recommended Reading References CHAPTER 12 Materials Safety Toxic Offgassing Materials Offgassing Controls Materials Testing...362

8 Contents xi Spacecraft Module Testing Stress-Corrosion Cracking What Is Stress-Corrosion Cracking? Prevention of Stress-Corrosion Cracking Testing Materials for Stress-Corrosion Cracking Design for Stress-Corrosion Cracking Requirements for Spacecraft Hardware Stress-Corrosion Cracking in Propulsion Systems Conclusions References CHAPTER 13 Oxygen Systems Safety Oxygen Pressure System Design Introduction Design Approach Oxygen Compatibility Assessment Process Oxygen Generators Electrochemical Systems for Oxygen Production Solid Fuel Oxygen Generators (Oxygen Candles) References CHAPTER 14 Avionics Safety Introduction to Avionics Safety Electrical Grounding and Electrical Bonding Defining Characteristics of an Electrical Ground Connection Control of Electric Current Electrical Grounds Can Be Signal Return Paths Where and How Electrical Grounds Should Be Connected Defining Characteristics of an Electrical Bond Types of Electrical Bonds Electrical Bond Considerations for Dissimilar Metals Electrical Ground and Bond Connections for Shields Recommended Reading Safety Critical Computer Control Partial Computer Control Total Computer Control: Fail Safe...413

9 xii Contents 14.4 Circuit Protection: Fusing Circuit Protection Methods Circuit Protectors Design Guidance Electrostatic Discharge Control Fundamentals Various Levels of Electrostatic Discharge Concern Recommended Reading Arc Tracking A New Failure Mode Characteristics of Arc Tracking Likelihood of an Arc Tracking Event Prevention of Arc Tracking Verification of Protection and Management of Hazards Summary Corona Control in High Voltage Systems Associated Environments Design Criteria Verification and Testing Recommended Reading Extravehicular Activity Considerations Displays and Indicators Used in Space Mating and Demating of Powered Connectors Single Strand Melting Points Battery Removal and Installation Computer or Operational Control of Inhibits Spacecraft Electromagnetic Interference and Electromagnetic Compatibility Control Electromagnetic Compatibility Needs for Space Applications Basic Electromagnetic Compatibility Interactions and a Safety Margin Mission Driven Electromagnetic Interference Design: The Case for Grounding Electromagnetic Compatibility Program for Spacecraft Design and Testing of Safety Critical Circuits Safety Critical Circuits: Conducted Mode Safety Critical Circuits: Radiated Mode...456

10 Contents xiii Electrical Hazards Introduction Electrical Shock Physiological Considerations Electrical Hazard Classification Leakage Current Bioinstrumentation Electrical Hazard Controls Verification of Electrical Hazard Controls Electrical Safety Design Considerations Avionics Lessons Learned Electronic Design Physical Design Materials and Sources Damage Avoidance System Aspects References CHAPTER 15 Software System Safety Introduction The Software Safety Problem System Accidents The Power and Limitations of Abstraction from Physical Design Reliability Versus Safety for Software Inadequate System Engineering Characteristics of Embedded Software Current Practice System Safety Best Practice Management of Software-Intensive, Safety-Critical Projects Basic System Safety Engineering Practices and Their Implications for Software Intensive Systems Specifications Requirements Analysis Model-Based Software Engineering and Software Reuse Software Architecture Software Design Design of Human-Computer Interaction...500

11 xiv Contents Software Reviews Verification and Assurance Operations Summary References CHAPTER 16 Battery Safety Introduction General Design and Safety Guidelines Battery Types Battery Models Hazard and Toxicity Categorization Battery Chemistry Alkaline Batteries Lithium Batteries Silver Zinc Batteries Lead Acid Batteries Nickel Cadmium Batteries Nickel Metal Hydride Batteries Nickel Hydrogen Batteries Lithium-Ion Batteries Storage, Transportation, and Handling References CHAPTER 17 Mechanical Systems Safety Safety Factors Types of Safety Factors Safety Factors Typical of Human Rated Space Programs Things That Influence the Choice of Safety Factors Spacecraft Structures Mechanical Requirements Space Mission Environment and Mechanical Loads Project Overview: Successive Designs and Iterative Verification of Structural Requirements Analytical Evaluations Structural Test Verification Spacecraft Structural Model Philosophy Materials and Processes Manufacturing of Spacecraft Structures Recommended Reading...566

12 Contents xv 17.3 Fracture Control Basic Requirements Implementation Summary Pressure Vessels, Lines, and Fittings Pressure Vessels Lines and Fittings Space Pressure Systems Standards Summary Composite Overwrapped Pressure Vessels The Composite Overwrapped Pressure Vessel System Monolithic Metallic Pressure Vessel Failure Modes Composite Overwrapped Pressure Vessel Failure Modes Composite Overwrapped Pressure Vessel Impact Sensitivity Summary Structural Design of Glass and Ceramic Components for Space System Safety Strength Characteristics of Glass and Ceramics Defining Loads and Environments Design Factors Meeting Life Requirements with Glass and Ceramics Safety Critical Mechanisms Designing for Failure Tolerance Design and Verification of Safety Critical Mechanisms Reduced Failure Tolerance Review of Safety Critical Mechanisms References CHAPTER 18 Containment of Hazardous Materials Toxic Materials Fundamentals of Toxicology Toxicological Risks to Air Quality in Spacecraft Risk Management Strategies Biohazardous Materials Microbiological Risks Associated with Spaceflight Risk Mitigation Approaches...622

13 xvi Contents Major Spaceflight Specific Microbiological Risks Shatterable Materials Shatterable Materials in a Habitable Compartment Program Implementation Containment Concepts for Internal Equipment Containment Concepts for Exterior Equipment General Comments About Working with Shatterable Materials Containment Design Approach Fault Tolerance Design for Minimum Risk Containment Design Methods Containment Environments Design of Containment Systems Safety Controls Proper Design Materials Selection Materials Compatibility Proper Workmanship Proper Loading or Filling Fracture Control Safety Verifications Strength Analysis Qualification Tests Acceptance Tests Proof Tests Qualification of Procedures Conclusions References CHAPTER 19 Failure Tolerance Design Safe Order of Precedence Hazard Hazard Controls Design to Tolerate Failures Hazardous Functions Must Not Work Hazardous Function Must Work Hazardous Function Design for Minimum Risk

14 Contents xvii 19.5 Conclusions References CHAPTER 20 Propellant Systems Safety Solid Propellant Propulsion Systems Safety Solid Propellants Solid Propellant Systems for Space Applications Safety Hazards Handling, Transport, and Storage Inadvertent Ignition Safe Ignition Systems Design Conclusions Liquid Propellant Propulsion Systems Safety Planning Containment Integrity Thermal Control Materials Compatibility Contamination Control Environmental Considerations Engine and Thruster Firing Inhibits Heightened Risk (Risk Creep) Instrumentation and Telemetry Data End to End Integrated Instrumentation, Controls, and Redundancy Verification Qualification Total Quality Management (ISO 9001 or Equivalent) Preservicing Integrity Verification Propellants Servicing Conclusions Hypergolic Propellants Materials Compatibility Material Degradation Hypergolic Propellant Degradation Propellant Fire Hydrazine and Monomethylhydrazine Vapor Liquid Hydrazine and Monomethylhydrazine Hydrazine and Monomethylhydrazine Mists, Droplets, and Sprays References

15 xviii Contents CHAPTER 21 Pyrotechnic Safety Pyrotechnic Devices Explosives Initiators Electroexplosive Devices Safe Handling of Electroexplosive Devices Designing for Safe Electroexplosive Device Operation Pyrotechnic Safety of Mechanically Initiated Explosive Devices References CHAPTER 22 Extravehicular Activity Safety Extravehicular Activity Environment Definitions Extravehicular Activity Space Suit Sensory Degradation Maneuvering and Weightlessness Glove Restrictions Crew Fatigue Thermal Environment Extravehicular Activity Tools Suit Hazards Inadvertent Contact Hazards Area of Effect Hazards Crew Hazards Contamination of the Habitable Environment Thermal Extremes Lasers Electrical Shock and Molten Metal Entrapment Emergency Ingress Collision Inadvertent Loss of Crew Conclusions References CHAPTER 23 Emergency, Caution, and Warning System System Overview Historic NASA Emergency, Caution, and Warning Systems

16 Contents xix 23.3 Emergency, Caution, and Warning System Measures Event Classification Measures Sensor Measures Data System Measures Annunciation Measures Failure Isolation and Recovery Reference CHAPTER 24 Laser Safety Background Optical Spectrum Biological Effects Laser Characteristics Laser Principles Laser Types Laser Standards NASA Johnson Space Center Requirements ANSI Standard Z Russian Standard Lasers Used in Space Radars Illumination Sensors Design Considerations for Laser Safety Ground Testing Unique Space Environment Conclusions References CHAPTER 25 Crew Training Safety: An Integrated Process Training the Crew for Safety Typical Training Flow Principles of Safety Training for the Different Training Phases Specific Safety Training for Different Equipment Categories Safety Training for Different Operations Categories Safety During Training Overview...770

17 xx Contents Training, Test, or Baseline Data Collection Model Versus Flight Model: Type, Fidelity, Source, Origin, and Category Training Environments and Facilities Training Models, Test Models, and Safety Requirements Training Model, Test Model, and Baseline Data Collection Equipment Utilization Requirements Qualification and Certification of Training Personnel Training and Test Model Documentation Training Development and Validation Process The Training Development Process The Training Review Process The Role of Safety in the Training Development and Validation Processes Feedback to the Safety Community from the Training Development and Validation Processes Conclusions References CHAPTER 26 Safety Considerations for the Ground Environment A Word About Ground Support Equipment Documentation and Reviews Roles and Responsibilities Contingency Planning Failure Tolerance Training Hazardous Operations Tools Human Factors Biological Systems and Materials Electrical Radiation Pressure Systems Ordinance Mechanical and Eelectromechanical Devices Propellants Cryogenics Oxygen Ground Handling

18 Contents xxi Software Safety Summary CHAPTER 27 Fire Safety Characteristics of Fire in Space Overview of Low Gravity Fire Fuel and Oxidizer Supply and Flame Behavior Fire Appearance and Signatures Flame Ignition and Spread Summary of Low Gravity Fire Characteristics Design for Fire Prevention Materials Flammability Ignition Sources Spacecraft Fire Detection Prior Spacecraft Systems Review of Low Gravity Smoke Spacecraft Atmospheric Dust Sensors for Fire Detection Spacecraft Fire Suppression Spacecraft Fire Suppression Methods Considerations for Spacecraft Fire Suppression References CHAPTER 28 Safe Without Services Design CHAPTER 29 Probabilistic Risk Assessment with Emphasis on Design Basic Elements of Probabilistic Risk Assessment Identification of Initiating Events Application of Event Sequence Diagrams and Event Trees Modeling of Pivotal Events Linkage and Quantification of Accident Scenarios Construction of a Probabilistic Risk Assessment for Design Evaluations Uses of Probabilistic Risk Assessment Reference Mission Relative Risk Evaluations Absolute Versus Relative Risk Assessments...899

19 xxii Contents Roles of Relative Risk Assessments in Design Evaluations Quantitative Evaluations Evaluations of the Relative Risks of Alternative Designs Overview of Probabilistic Risk Assessment Models Developed Relative Risk Comparisons of the Alternative Designs References Index