Software errors cost the U.S. economy $60 billion annually in rework, lost productivity and actual damages. We all know software bugs can be annoying, but faulty software can also be expensive, embarrassing, destructive and deadly. Following are 20 famous software “disasters” in chronological order:

1. Mariner Bugs Out (1962)

Cost: $18.5 million

Disaster: The Mariner 1 rocket with a space probe headed for Venus diverted from its intended flight path shortly after launch. Mission Control destroyed the rocket 293 seconds after liftoff.

Cause: A programmer incorrectly transcribed a handwritten formula into computer code, missing a single superscript bar. Without the smoothing function indicated by the bar, the software treated normal variations of velocity as if they were serious, causing faulty corrections that sent the rocket off course. (more)

2. Hartford Coliseum Collapse (1978)

Cost: $70 million, plus another $20 million damage to the local economy

Disaster: Just hours after thousands of fans had left the Hartford Coliseum, the steel-latticed roof collapsed under the weight of wet snow.

Cause: The programmer of the CAD software used to design the coliseum incorrectly assumed the steel roof supports would only face pure compression. But when one of the supports unexpectedly buckled from the snow, it set off a chain reaction that brought down the other roof sections like dominoes. (more)

3. CIA Gives the Soviets Gas (1982)

Cost: Millions of dollars, significant damage to Soviet economy

Disaster: Control software went haywire and produced intense pressure in the Trans-Siberian gas pipeline, resulting in the largest man-made non-nuclear explosion in Earth’s history.

Cause: CIA operatives allegedly planted a bug in a Canadian computer system purchased by the Soviets to control their gas pipelines. The purchase was part of a strategic Soviet plan to steal or covertly obtain sensitive U.S. technology. When the CIA discovered the purchase, they sabotaged the software so that it would pass Soviet inspection but fail in operation. (more)

4. World War III… Almost (1983)

Cost: Nearly all of humanity

Disaster: The Soviet early warning system falsely indicated the United States had launched five ballistic missiles. Fortunately the Soviet duty officer had a “funny feeling in my gut” and reasoned if the U.S. was really attacking they would launch more than five missiles, so he reported the apparent attack as a false alarm.

Cause: A bug in the Soviet software failed to filter out false missile detections caused by sunlight reflecting off cloud-tops. (more)

5. Medical Machine Kills (1985)

Cost: Three people dead, three people critically injured

Disaster: Canada’s Therac-25 radiation therapy machine malfunctioned and delivered lethal radiation doses to patients.

Cause: Because of a subtle bug called a race condition, a technician could accidentally configure Therac-25 so the electron beam would fire in high-power mode without the proper patient shielding. (more)

Wait, there’s more… Continue to Part 2

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Article published on February 12, 2008