Failure of Process / Failure of Mission Mars Climate Orbiter Gerry Tucker [2021275825] (got150030@utdallas.edu) EMSE 6361 – Fall 2015 Term Paper – Interim http://utdallas.edu/~got150030/emse6361/

Case Study Overview

Case Study Overview* Mars Climate Orbiter (MCO) launched Dec. 11, 1998 with an anticipated arrival at Mars of Sept. 1999 On Sept. 23, 1999 all contact was lost as MCO was 4 minutes into the Mars Orbital Insertion (MOI) burn On Sept. 29, 1999 the root cause of the failure was discovered *Background information derived from MCO Mishap Investigation Board Phase 1 Report

Prime contractor for vehicle development Case Study Primaries Lead NASA center for Mars Surveyor Program Project office created by JPL with the responsibility to define the mission, develop the spacecraft / payload elements, and integrate/test/launch the flight system.* Prime contractor for vehicle development *Background information derived from MCO Mishap Investigation Board Phase 1 Report

Vehicle Positioning / Trajectory Process Mission critical process for ensuring vehicle is aligned properly for orbit insertion Angular Momentum Desaturation (AMD) process utilizes thruster firings to keep spacecraft within operational range AMD Event Occurs Vehicle Trajectory Modeling Small Forces Processing Data AMD File

Project Timeline Dec. 11, 1998 Dec. 1998 – April 1999 April 1999 – Sept. 1999 Sept. 23, 1999 Sept. 29, 1999 Vehicle Launch Vehicle Modeling using informal AMD timing (via email) Vehicle Modeling using AMD file Loss of Vehicle Initial Root Cause Discovered Began to notice discrepancies in data Errors in format of file prevented use

Direct Root Cause

Root Cause* AMD Event Occurs Vehicle Trajectory Modeling Small Forces Processing Data AMD File Units = Newtons Units = lbf-s *Background information derived from MCO Mishap Investigation Board Phase 1 Report

Root Cause* - Consequence Result was a small error build up Vehicle entered the atmosphere at a periapsis of 57km Lowest projected by model using the fault data was 110km Lowest survivable periapsis: 80km Figure 4 form MCO Mishap Investigation Board Phase 1 Report * *Background information derived from MCO Mishap Investigation Board Phase 1 Report

Root Cause Analysis

Root Cause Analysis Why did unit conversion issue cause mission failure? Conversion issue not found during validation testing. Why? Failure in program validation process. Failure in developer quality process. Operations processed without formal AMD data. Why? Failure in project schedule and risk management. Operations noticed small inconsistencies throughout mission, but did not formally raise issue. Why? Failure in project planning for transition to operations (lack of training).

Problem 1 (P1) Failure in program validation process. System integration testing failed to validate that the interface of the AMD file was satisfied correctly.

Problem 2 (P2) Failure in developer quality process. Developer had a clear specification that indicated the units required for the AMD file. Quality process should have enforced some sort of review that would catch something as critical as the requirements of the interface.

Problem 3 (P3) Failure in project schedule and risk management. Project management attempted to mitigate the late schedule of the developer providing an in spec AMD file with a manual interaction. Given the criticality of this particular system function, it is not clear that the risk was properly quantified. Mitigation plan not thorough enough to require validation of AMD interface upon receipt of late system function. Contributing factor to P1.

Problem 4 (P4) Failure in project planning for transition to operations (lack of training). Operations team responsible for utilizing AMD interface was not part of original program development Thorough background training on the specifications of the system was not provided This lack of background knowledge contributed to the issue of operations noticing minor inconsistencies in the data without realizing the larger consequence to the system

References

References Mars Climate Orbiter Mishap Investigation Report – Phase 1 Report: Nov. 10, 1999; Stephenson, Mulville, Bauer, etc. [ftp://ftp.hq.nasa.gov/pub/pao/reports/1999/MCO_report.pdf] Slide 4,5,8 – JPL Logo - http://www.jpl.nasa.gov/ Slide 4,5,8,12,14,15 – Lockheed Martin Logo - http://www.lockheedmartin.com/ Slide 4,11,14,15 – Mars Surveyor Logo http://mars.jpl.nasa.gov/msp98/gif/m98patch.gif Slide 5, 8 – MCO Picture http://www.jpl.nasa.gov/jplhistory/the90/images/climate-orbiter- browse.jpg