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ACIS Science Instrument Software Fault Tolerance and Failure Modes and Effects Analysis

1.0 , Introduction

The AXAF-I CCD Imaging Spectrometer (ACIS) Science Instrument Software is being developed by the Massachusetts Institute of Technology, Center for Space Research (MIT-CSR) as part of the ACIS Digital Processor Assembly (DPA). The DPA resides on-board the Advanced X-ray Astrophysics Facility - Imaging (AXAF-I). The DPA Science Instrument Software is responsible for acquiring and processing image data from the ACIS CCD Imaging Spectrometer and transferring the processed data to the AXAF-I Command and Telemetry Unit (CTU), which is then responsible for sending the information to the ground.

1.1 Purpose

The ACIS Science Instrument Software Fault Tolerance and Failure Modes and Effects Analysis (FT&FMEA) defines the degree of fault tolerance, effect and criticality of the instrument software, and defines the means by which the software detects and handles the defined faults. All faults analyzed in this document are identified and described in the ACIS instrument-level FMEA.

NOTE: At this time, no instrument-level failures have been documented in the instrument FMEA which affect the software. As a result, this document is currently serving only as a template. As the instrument FMEA is further refined, any identified failures which affect the software will be analyzed and incorporated into this document.

1.2 Scope

This document applies to the design of the ACIS DPA Science Instrument Software. It does not provide information for the Ground Support Software (GSS), which is maintained separately as part of the Electronic Ground Support Equipment (EGSE).

This document supplies information applicable to the software portion of SPA04, and to DM07 from MM8075.1.

By mutual agreement, MSFC Software Management and Development Requirements Manual MM8075.1 which supersedes MA-001-006-2H, forms the basis for this plan.

1.3 References

TABLE 1. Reference Documents 
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Part Number       Version           Title                                      
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MSFC MM 8075.1    January 22, 1991  MSFC Software Management and Develop       
                                    ment Requirements Manual                   
MIT-CSR 36-02402  01                ACIS SIS Preliminary Design Specification  
MIT-CSR 36-01406  01                ACIS Failure Modes and Effects Analysis    
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