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 OperationsPage 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 OperationsPage 3

Mission Success Diagram

R(mission) = R(LV) x R(Satellite) x R(Ground System)

R(Satellite) = R(Spacecraft) x R(Instrument)

Launch Vehicle

InstrumentsSpacecraftGround System

SNAP, June 25-28, 2001 Goddard Space Flight Center

Mission/Science OperationsPage 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 OperationsPage 5

RSDO Bus Reliability

RSDO Buses Proposed as Base Design StarBus: 98% @ 2 years, 95% @ 5 years MidStar: 95% @ 2 years, 88.6% @ 5 years BCP 2000: 95% @ 2 years, 88.6% @ 5 years SA-200HP: 91% @ 2 years, 79% @ 5 years

Full Redundancy Option: 99% @ 2 years, 96% @ 5 years LM 900:87.6% @ 2 years, 72% @ 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 OperationsPage 6

Instrument Reliability Requirement

2 year Bus/ I nstr. Rel. = .85 2 year Bus/ I nstr. Rel. = .90 S/ C Bus *Bus Rel. I nstr. Rel. *Bus Rel. I nstr. Rel.

LM 900 .876 .97 .876 - SA-200HP .91 .93 .91 .99 MidStar .95 .89 .95 .95 BCP2000 .95 .89 .95 .95 StarBus .98 .87 .98 .92 SA-200HP w/ f ull redundancy

.99 .86 .99 .91

* Based on manufacturer provided data, but actual buses may require signifi cant modifi cations to meet mission needs

SNAP, June 25-28, 2001 Goddard Space Flight Center

Mission/Science OperationsPage 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 OperationsPage 8

Safety Overview-(Delta/Atlas)

Safety Process Overview (Delta/Atlas) Protection of Public, Personnel, and Assets Preliminary Hazard Analysis Tailoring of EWR 127-1 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 OperationsPage 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 D688-10009-1, Section 11. Sea Launch Safety Plan, Boeing Document D688-10014-1. 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