Mars Climate Orbiter Mission – 1999 Incident

Introduction

• The incident is considered one of the space industry's biggest failures.
• Famous for demonstrating the consequences of mixing metric and imperial units.

Background

• In the late 1990s, NASA was directed to make missions faster, smaller, and cheaper.
• NASA launched the "Mars Surveyor 98" program which included:
  • Mars Polar Lander
  • A pair of impact microprobes
  • Mars Climate Orbiter (intended to study Martian weather)

Mars Climate Orbiter Design

• Low mass, fitted with a single solar panel rated at 500 watts at Mars.
• Asymmetrical design caused rotational forces from the solar wind.
• Corrective measures included thruster burns to reset reaction wheels, recorded in a file.

The Critical Mistake

• Lockheed Martin was contracted to use metric units.
• Files mistakenly contained measurements in imperial units (pounds of force per second) instead of metric (Newtons).
• Result: Thruster operations were underestimated by a factor of 4.45, putting the craft on the wrong trajectory.

Detection and Consequences

• NASA's Jet Propulsion Laboratory (JPL) noticed more adjustments than expected but didn't raise concerns formally.
• One day before arrival, calculations showed the probe might be off-course.
• Team discussed a contingency burn but didn’t execute it due to timing and uncertainty.
• Probe entered Mars atmosphere at 37 miles (60 km) altitude and was destroyed.

Aftermath

• A report criticized lack of communication and training within NASA and with Lockheed Martin.
• Lessons learned were applied in developing the Mars Reconnaissance Orbiter 5 years later, exclusively using metric units.
• Incident attributed to human error – incorrect data input leading to incorrect calculations.

Learning Resources

• Mention of Brilliant.org for learning problem-solving and calculations relevant to space exploration and other scientific fields.
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