Cassini Program EIS Supporting Study Volume 3 · PDF file3.2 THE BASELINE CASSINI MISSION...
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Transcript of Cassini Program EIS Supporting Study Volume 3 · PDF file3.2 THE BASELINE CASSINI MISSION...
CONTENTS
GLOSSARY OF TERMS AND ACRONYMS ............................................................................. xv
O. OVERVIEW........................................................................................................................... O-1
O.1 INTRODUCTION.......................................................................................................... O-1
O.2 METHODOLOGY......................................................................................................... O-2
O.3 FAILURE MODE ANALYSIS...................................................................................... O-3
O.4 SHORT-TERM EARTH IMPACT PROBABILITY ..................................................... O-5
O.5 LONG-TERM EARTH IMPACT PROBABILITY ....................................................... O-5
O.6 EARTH IMPACT PROBABILITY ASSESSMENT ..................................................... O-7
1. INTRODUCTION .................................................................................................................. 1-1
1.1 PURPOSE OF THE STUDY .......................................................................................... 1-1
1.2 ORGANIZATION OF THE DOCUMENT..................................................................... 1-2
2. METHODOLOGY ................................................................................................................. 2-1
2.1 INTRODUCTION........................................................................................................... 2-1
2.2 SHORT-TERM EARTH IMPACT LOGIC DIAGRAM ................................................ 2-4
2.3 LONG-TERM EARTH IMPACT LOGIC DIAGRAM .................................................. 2-6
2.4 FAILURE MODE ANALYSIS....................................................................................... 2-8
2.5 SHORT-TERM IMPACT PROBABILITY .................................................................... 2-9
2.6 LONG-TERM IMPACT PROBABILITY ...................................................................... 2-11
2.7 EARTH IMPACT PROBABILITY ASSESSMENT ...................................................... 2-13
3. PROGRAM DESCRIPTION.................................................................................................. 3-1
3.1 CASSINI ORBITER DESCRIPTION............................................................................. 3-1
3.1.1 Orbiter Subsystems .............................................................................................. 3-1
3.2 THE BASELINE CASSINI MISSION DESIGN............................................................ 3-11
3.2.1 The Baseline Primary Mission Design .............................................................. 3-11
3.2.2 The Baseline Backup Mission Design ............................................................... 3-12
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3.3 NAVIGATION SYSTEM................................................................................................ 3-14
3.3.1 Introduction........................................................................................................ 3-14
3.3.2 JPL Navigation System ...................................................................................... 3-14
3.3.3 Orbit Knowledge Determination forEarth Swingby.................................................................................................... 3-24
3.4 UPLINK PROCESS OVERVIEW................................................................................... 3-25
3.4.1 Uplink Definitions.............................................................................................. 3-26
3.4.2 Uplink Operations Organization......................................................................... 3-28
3.4.3 Uplink Subprocesses .......................................................................................... 3 -30
4. FAILURE MODES................................................................................................................. 4-1
4.1 METHODOLOGY........................................................................................................... 4-1
4.1.1 Introduction........................................................................................................ 4-1
4.1.2 Estimate Uncertainties........................................................................................ 4-1
4.1.3 Logic Diagram ................................................................................................... 4-2
4.1.4 Summary of Results ........................................................................................... 4-2
4.2 V-INDUCING FAILURES .......................................................................................... 4-5
4.2.1 Micrometeoroid-Induced Failures ...................................................................... 4-5
4.2.2 Internal Spacecraft Failures ............................................................................... 4-24
4.2.3 Ground-Induced Errors ...................................................................................... 4-35
4.3 PROBABILITY OF NO RECOVERY (PNR) ................................................................... 4-43
4.3.1 PNR for Failures Occurring BeforeE-39 Days........................................................................................................... 4-43
4.3.2 PNR for Failures Occurring BetweenE-39 Days and E-2 Days .................................................................................... 4-47
4.3.3 PNR for Failures Occurring BetweenE-2 Days and E-0 Days .................................................................................... 4-51
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5 SHORT-TERM EARTH IMPACT PROBABILITY .............................................................. 5-1
5.1 INTRODUCTION............................................................................................................ 5-1
5.2 IMPACT OF FAILURES ON TRAJECTORY................................................................ 5-1
5.3 EARTH IMPACT AND PROBABILITIES..................................................................... 5-3
5.3.1 Calculation Of Type I FailureImpact Probabilities ......................................................................................... 5-5
5.3.2 Calculation of Type II FailureImpact Probabilities ........................................................................................... 5-7
5.4 EARTH SWINGBY NAVIGATION STRATEGY 5-9
5.4.1 Ground Rules for Type I andOther Failures..................................................................................................... 5-10
5.5 MANEUVER STRATEGY ............................................................................................. 5-11
5.6 METHOD OF COMPUTATION..................................................................................... 5-18
5.6.1 Model and Process Uncertainty.......................................................................... 5-18
5.6.2 Impact Probability Estimation Process............................................................... 5-19
5.6.3 Navigation Models............................................................................................. 5-2 0
5.6.4 Other Calculations.............................................................................................. 5-21
5.7 EARTH IMPACT PROBABILITIES .............................................................................. 5-22
5.8 NUMERICAL RESULTS................................................................................................ 5-26
5.9 SUMMARY..................................................................................................................... 5-27
6. LONG-TERM EARTH IMPACT PROBABILITY ................................................................ 6-1
6.1 INTRODUCTION............................................................................................................ 6-1
6.2 METHOD ........................................................................................................................ 6-1
6.2.1 Monte Carlo Case Formulation............................................................................ 6-7
6.2.2 Orbital Geometry Required for Impact ................................................................ 6-9
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6.3 RESULTS ........................................................................................................................ 6-14
6.3.1 Uncertainty Analysis .......................................................................................... 6-14
6.3.2 Long-Term Earth Impact Probability ................................................................. 6-17
6.3.3 Entry Angle, Velocity, andLatitude Distribution .......................................................................................... 6-22
6.3.4 Very Long-Term Earth Impact Analysis ............................................................... 6-27
6.4 CONCLUSIONS .............................................................................................................. 6-27
7. EARTH IMPACT PROBABILITY ASSESSMENT .............................................................. 7-1
APPENDIXES
A. BAYESIAN CALIBRATION OF THE MICROMETEOROIDMODEL ..................................................................................................................... A-1
B. ANOMALOUS V EFFECTS FOR MICROMETEOROIDAND
