The Greatest Mathematical Error
The Mariner I space probe was launched from Cape Canaveral on 28
July 1962 towards Venus. After 13 minutes' flight a booster engine would
give acceleration up to 25,820 mph; after 44 minutes 9,800 solar cells
would unfold; after 80 days a computer would calculate the final course
corrections and after 100 days the craft would cirlce the unknown planet,
scanning the mysterious cloud in which it is bathed.
However, with an efficiency that is truly heartening, Mariner I
plunged into the Atlantic Ocean only four minutes after takeoff.
Inquiries later revealed that a minus sign had been omitted from
the instructions fed into the computer. "It was human error", a launch
This minus sign cost L4,280,000.
- -- Stephen Pile, "The Book of Heroic Failures"