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Software Bug in Mars Climate Orbiter

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The name of that mission was Mars Climate Orbiter (MCO) ... a human error, and ended with a system failure witch led to the mission failure. ... – PowerPoint PPT presentation

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Title: Software Bug in Mars Climate Orbiter


1
Software Bug in Mars Climate Orbiter
  • Ala Aldin Meriden (Aladdin)
  • EE 585-001
  • Fall 2006
  • In-class Presentation 1
  • Dr.James Lumpp

2
Outline
  • Introduction
  • The problem
  • Example
  • The results
  • The consequences
  • Conclusion
  • References

3
Introduction
  • The name of that mission was Mars Climate Orbiter
    (MCO).
  • The MCO spacecraft was lunched by Delta rocket on
    December 11, 1998.
  • The MCO was lunched from Cape Canaveral Air
    Station, Florida.
  • After 9½ months the spacecraft was to reemerge
    from behind Mars , did not occur.
  • The MCO was to have used a technique called
    aerobraking. (Look at the figure next slide).
  • The bug occurred because two teams of that
    mission, one was in Colorado and the other was in
    California, were using two different units.

4
Introduction (cont.)
5
The Problem
  • The cause of the error was A failure to
    recognize and correct an error transfer of
    information between the MCO spacecraft team in
    Colorado and the mission Navigation team in
    California
  • One team used English Unites (e.g. inches, feet
    and pound) while the other used metric units for
    a key spacecraft operation.

6
The Problem (cont.)
  • The Angular Momentum Distribution (AMD) file
    contained the output data from the software
    application code, Small Forces, which was using
    the English units.
  • On the other hand, MSOP project Software
    Interface Specification was to be in metric
    unites.

7
Example
  • 1 inch 2.6 cm
  • 12 inch 31.2cm
  • 1 cm 0.385 inch
  • 12 cm 4.615 inch
  • 1 0.385 0.615 inches different

8
The Results
  • Therefore, the actual trajectory was lower than
    the expected trajectory, and it was not detected
    because of the mismatch of unites of measurement
    used in the navigation software and the
    propulsion system.

9
The Results (cont.)
  • So, they lost communications with MCO, and it is
    presumed to have broken up in the Martian
    atmosphere, or crashed on the planet.
  • There were indications that this bug could have
    been picked up, between the times the MCO was
    launched, and just before it was due to enter
    Mars orbit.

10
The Results (cont.)
11
The Consequences
  • The total cost of the spacecraft development and
    mission operations of this project was US 235.9
    million.
  • Delay of scientific missions
  • MSO was designed to help scientists better
    understand the climate history of Mars.
  • The MSO was to be the First Martian Weather
    Satellite.
  • The MSO carries two science instruments
  • The pressure Modulator Infrared Radiometer.
  • The Mars Color Imager.
  • Concerns over the Mars Polar Lander.
  • Concerns over NASA policies.

12
Conclusion
  • The root cause for the loss of the Mars Climate
    Orbiter in September 1999, was due to the failure
    to convert the outputted Imperial measurements to
    the required metric measurements, within a
    specific piece of ground software.
  • This bug started with a human error, and ended
    with a system failure witch led to the mission
    failure.
  • This case study highlights issues of
    interoperability between different components,
    and the difficulty of the verification of a
    system as a whole.

13
References
  • Jet Propulsion Laboratory, California Institute
    of Technology, National Aeronautics and Space
    Administration (1999). NASA'S MARS CLIMATE
    ORBITER BELIEED TO BE LOST. http//marsweb.jpl.nas
    a.gov/msp98/news/mco990923.html
  • Jet Propulsion Laboratory, California Institute
    of Technology, National Aeronautics and Space
    Administration (1999). Mars Climate Orbiter
    Mission Status. http//marsweb.jpl.nasa.gov/msp98/
    news/mco990924.html
  • Isbell, D., Hardin, M. and Underwood, J. (1999).
    MARS CLIMATE ORBITER TEAM FINDS LIKELY CAUSE OF
    LOSS. http//marsweb.jpl.nasa.gov/msp98/news/mco99
    0930.html

14
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