History of Mars Climate Orbiter in Timeline

By Popular Timelines Editorial Team · Updated: April 1, 2026

The Mars Climate Orbiter was a NASA space probe launched in 1998 to study the Martian climate and atmosphere, and to serve as a communications relay. Communication was lost in September 1999 during orbital insertion, and the probe was destroyed. The failure was attributed to a critical measurement mismatch: NASA used metric units while Lockheed Martin, the spacecraft builder, used US customary units. This resulted in the probe entering the Martian atmosphere at a dangerously low altitude.

1994: Panel on Small Spacecraft Technology Established

In 1994, the Panel on Small Spacecraft Technology was established to set guidelines for future miniature spacecraft, recommending spacecraft under 1,000 kg with focused instrumentation.

1995: Mars Surveyor Program Begins

In 1995, NASA initiated a new Mars Surveyor program designed for limited objectives, low costs, and frequent launches.

1996: Mars Global Surveyor Launched

In 1996, the first mission of the new Mars Surveyor program, Mars Global Surveyor, was launched to map Mars and gather geologic data.

December 11, 1998: Mars Climate Orbiter Launch

On December 11, 1998, NASA launched the Mars Climate Orbiter to study the Martian climate and atmosphere and act as a communication relay for the Mars Polar Lander.

September 8, 1999: Trajectory Correction Maneuver-4 (TCM-4) Computed

On September 8, 1999, Trajectory Correction Maneuver-4 (TCM-4) was computed to place the spacecraft at an optimal position for orbital insertion.

September 15, 1999: Trajectory Correction Maneuver-4 (TCM-4) Executed

On September 15, 1999, Trajectory Correction Maneuver-4 (TCM-4) was executed, intended to place the spacecraft for an orbital insertion maneuver at an altitude of 226 km on September 23, 1999.

September 23, 1999: Loss of Communication

On September 23, 1999, communication with the Mars Climate Orbiter was permanently lost as it entered orbital insertion. The spacecraft was destroyed in the Martian atmosphere due to a trajectory error.

November 10, 1999: Mishap Investigation Board Phase I Report Released

On November 10, 1999, the Mars Climate Orbiter Mishap Investigation Board released a Phase I report, detailing the suspected issues with the loss of the spacecraft.

December 3, 1999: Expected Landing of Mars Polar Lander

On December 3, 1999, the Mars Climate Orbiter was intended to relay communications with Mars Polar Lander upon its expected landing.

2024: Mission Cost in 2024 Dollars

According to NASA, in 2024, the cost of the Mars Climate Orbiter mission was $586.41 million, comprising $345.65 million for spacecraft development, $164.14 million for launching, and $76.61 million for mission operations.