Supernova/Acceleration Probe (SNAP) Reliability & System Safety Dick Bolt David Bogart June 28, 2001

SNAP, June 25-28, 2001 Goddard Space Flight Center Mission/Science Operations Page 2 Reliability Requirements  Mission/System  Mission life of 2 years required, and a goal of 5 years desired  Probability of mission success  Instrument  Spectroscopy data, while ~1% of total data stream, is high priority since small loss of this data is not recoverable through statistical techniques

SNAP, June 25-28, 2001 Goddard Space Flight Center Mission/Science Operations Page 3 Mission Success Diagram  R(mission) = R(LV) x R(Satellite) x R(Ground System)  R(Satellite) = R(Spacecraft) x R(Instrument) Launch Vehicle Instruments Spacecraft Ground System

SNAP, June 25-28, 2001 Goddard Space Flight Center Mission/Science Operations Page 4 Launch Vehicle  Delta III  Reliability of launch vehicle not well established at this time  Atlas IV  Reliability of launch vehicle not well established at this time  Sea Launch - Zenit-3SL  Demonstrated reliability of 85.7% (6 successful launches out of 7)  Sea Launch calculated reliability of 93.7%  Sea Launch people likely have reevaluated reliability based on fixes for their launch failure  Need to see data and numbers  Need to see if any other failures occurred in past 6 launches that did not result in launch failure

SNAP, June 25-28, 2001 Goddard Space Flight Center Mission/Science Operations Page 5 RSDO Bus Reliability  RSDO Buses Proposed as Base Design  2 years, 5 years  2 years, 5 years  BCP 2 years, 5 years  2 years, 5 years  Full Redundancy Option: 2 years, 5 years  LM 2 years, 5 years  Each of the RSDO Buses require significant modifications to meet mission requirements. These modifications will likely have a significant effect on reliability estimates.

SNAP, June 25-28, 2001 Goddard Space Flight Center Mission/Science Operations Page 6 Instrument Reliability Requirement

SNAP, June 25-28, 2001 Goddard Space Flight Center Mission/Science Operations Page 7 Reliability Considerations  Recommend Probabilistic Risk Assessment (PRA) to identify key areas for redundancy/high qual parts  Reliability Predictions, Fault Tree Analysis, Failure Modes and Effects Analysis  Spectroscopy Data  Storage of Spectroscopy Data to Ensure Data  Allow Spectroscopy to be sent via S-Band as back up.  RF  High Data Rates - Ka Unit  Ka Band XMTR Reliability Data from DoD sources  Optical Imager  Effects of lost pixels on science data  Consider redundant means to open instrument shutter  Consider redundant means to select filter position

SNAP, June 25-28, 2001 Goddard Space Flight Center Mission/Science Operations Page 8 Safety Overview-(Delta/Atlas)  Safety Process Overview (Delta/Atlas)  Protection of Public, Personnel, and Assets  Preliminary Hazard Analysis  Tailoring of EWR  Preparation and Submittal of Missile System Prelaunch Safety Package (MSPSP)  Review and Approval of MSPSP by Range Safety  Closure of any action items/verifications required by MSPSP/Range Safety

SNAP, June 25-28, 2001 Goddard Space Flight Center Mission/Science Operations Page 9 System Safety-(SeaLaunch)  SeaLaunch Safety Considerations  Evaluation and approval of SeaLaunch S&MA Director  Licensing by the U.S. DOT of the Associate Administrator for Commercial Space Transportation (FAA/AST)  Safety review schedule and data submittal agreements established during initial customer interface meeting. Basic requirements identified in the SeaLaunch User’s Guide, Boeing Doc D , Section 11.  Sea Launch Safety Plan, Boeing Document D  Three phase safety review process  Preliminary Design Review (PDR)  Critical Design Review (CDR)  Ground Operations Readiness Review (GORR)  Iterative process of  Defining requirements  Identifying hazards  Identify hazard controls  Verify hazard controls