In September of 1999, NASA ambitiously launched a Mars weather satellite. But the satellite did not even reach its destination, instead exploding in the atmosphere soon after launch. Why was this? The reason was so stupidly simple. The failure was because of units.
The satellite that was designed by Lockheed Martin was designed using the imperial system (pounds, feet and yards), whereas NASA’s systems used the internationally-used metric system. Because of this simple error, the pride of the USA space program fell to the ground and an astronomical amount of money was burnt to ashes in the air.