A quick introduction to what happened to the Mars Climate Orbiter. The MCO was supposed to work as a communication relay for the Mars Planetary Lander. In 1994, NASA established the Mars Survey Program (MSP). They launched the Orbiter and the Lander in 1998. As proposed, the spacecraft was meant to enter Mars’ orbit on September 1999. Unfortunately, while the entering the orbit, the Orbiter was so fast, that the it was flying below the minimum height required. The main reason for this mishap was due to the usage of wrong units, that is, the software installed in spacecraft was in Imperial Unit while the ground team on Earth was calculating in terms of Metric Unit.