Oops! NASA once lost a $125 million flight because Engineers Forgot to Convert to Metric

Here’s what you’ll learn by reading this story:

• The Mars Climate Orbiter (MCO) was launched in late 1998 and was predicted to reach Mars nine months later. But that didn’t happen.

• When the MCO approached Mars, it got too close and either burned up in the atmosphere or got lost in some other way.

• A postmortem examination by NASA later determined that the failure of the mission was caused by their contractor, Lockheed Martin, not caring to convert the metric units into the software.

December 11, 1998—launch date of the Mars Climate Orbiter (MCO) and its companion Polar Lander, both part of a larger NASA project known as Mars Surveyor ’98. NASA had commissioned Lockheed Martin to design and build the MCO, which was intended to collect Martian weather data while communicating with the Polar Lander.

There was only one problem: The orbiter would not reach Mars.

On the surface, everything seemed to be going according to plan. Lockheed Martin was the design lead, and NASA’s Jet Propulsion Laboratory (JPL) oversaw every aspect of the project. The MCO had eight thrusters designed to lift it into Mars orbit. It also had wheels that could change its height and position, although they sometimes over-speed, causing the MCO to require an angular momentum desaturation (AMD) event to regenerate itself. Once in orbit, the MCO had to return data to special software on Earth, which would know its position and plan any necessary AMD events for the near future.

That communication was important, as it is for all space missions. But soon after launch, software problems began to appear. During the trip, which was expected to last nine and a half months, the MCO software began to malfunction, requiring ground motion data to be emailed to NASA for processing. Despite fixes to the software, however, the MCO was still transmitting nonsense data back to Earth.

In September 1999, engineers calculated and executed the final proposed Trajectory Correction Maneuver (TCM-4) to improve the Mars Climate Orbiter’s approach to Mars. The proposed trajectory would have produced an initial periapsis (closest to Mars) of about 140 miles (226 km) above the planet after entering orbit. But the astronauts determined that the spacecraft’s predicted trajectory was lower than expected, which revealed a serious error in the trajectory. The planet’s gravity was beginning to pull the delegation.

On the morning of September 23, 1999, the MCO had disappeared with no means of re-establishing contact. So…what happened?

According to NASA’s first fatality analysis, the spacecraft was only 35 miles (57 km) from Mars’ red light when contact was lost. Engineers concluded that the orbiter burned up in the Martian atmosphere or jumped the atmosphere and was lost in space. When the agency investigated the following month and discovered the issue of the data, it noticed something suspicious about the small power software that was responsible for determining the level of MCO and AMD: while everything used metric units, this software used Imperial units.

Lockheed Martin’s use of faulty components in its software meant that MCO was nowhere near where it should have been. While NASA required Lockheed Martin to convert its measurements into metric units, the agency has not confirmed which measurement system the company used before sending the MCO to Mars, and it is reported that there was no response from the top management when the crew gave their opinion during the mission.

Investigators said NASA is the party responsible for the mission failure, rather than Lockheed Martin. They said that NASA officials rushed everything to destroy the project, neglecting to thoroughly check the small equipment in the way they should have, and that it was impossible to say whether the system engineering team had confirmed and validated the software to begin with.

Unfortunately, regardless of whose fault it was, the Mars Polar Lander suffered from a failure of the conversion unit. Shortly after this simple mistake veered dangerously off course, it was doomed to crash and burn.

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