On this day in tech history, the Mariner 1 probe heading toward Venus had to be destroyed after veering off course due to equipment failure and an error in coded computer instructions.

Mariner 1 was the first spacecraft in the American Mariner program (see NASA illustration below). It was launched on July 22, 1962 from Cape Canaveral on a mission to collect a variety of scientific data about Venus during a flyby.

Just 293 seconds after launch, a range safety officer ordered a destructive abort when it veered off course after an unscheduled yaw-lift maneuver. The destruct command was sent six seconds before separation, after which it could not have been destroyed (see video below).

Faulty application of guidance commands made steering impossible, and were directing the spacecraft toward a crash, possibly in the North Atlantic shipping lanes or in an inhabited area.

Improper operation of the Atlas airborne beacon equipment caused multiple periods of time without a rate signal. The post-flight review also showed that a missing hyphen in coded computer instructions in the data-editing program allowed transmission of incorrect guidance signals.

When the airborne beacon wasn’t working, the code error caused the computer to accept the sweep frequency of the ground receiver as it sought the vehicle beacon signal and combined that with tracking data sent to the guidance computation. That led to unnecessary course corrections with incorrect steering commands.

Speculation on the failure of Mariner 1 also pointed to the pressure of the Space Race. Some have called the spacecraft hastily built, as NASA tried to keep up with the Soviets, who made multiple attempts to fly by Venus in the early 1960s.

NASA engineers had been working on a new design specifically for going to Mars and Venus, but it wasn’t ready in time for the 1962 attempt, so Ranger spacecraft were used for Mariner 1 and its backup, Mariner 2.

On December 14, 1962, Mariner 2 became the first robotic space probe to conduct a successful planetary encounter. It collected data on Venus’ atmosphere, magnetic field, charged particle environment, and mass, as well as measurements of the interplanetary medium.

The cost of Mariners 1 through 10 was approximately $554 million, making that missing hyphen an expensive mistake.

Learn more about the history of NASA’s planetary exploration in this video celebrating the Mariner program’s 50th anniversary:

Video from the NASA Jet Propulsion Laboratory California Institute of Technology



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For more moments in tech history, see this blog. EDN strives to be historically accurate with these postings. Should you see an error, please notify us.



Editor’s note: This article was originally posted on July 22, 2013 and edited on July 22, 2019.

