1. Failure of Process / Failure of Mission
Mars Climate Orbiter
Gerry Tucker [ ]
EMSE 6361 – Fall 2015
Term Paper – Interim

2. Case Study Overview

3. 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

4. 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

5. 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

6. 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 )
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

7. Direct Root Cause

8. 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

9. 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

10. Root Cause Analysis

11. 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).

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

13. 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.

14. 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.

15. 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

16. References

17. 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 -
Slide 4,5,8,12,14,15 – Lockheed Martin Logo -
Slide 4,11,14,15 – Mars Surveyor Logo
Slide 5, 8 – MCO Picture browse.jpg