#readwise # Mariner 1 - Wikipedia  ## Metadata - Author: [[en.wikipedia.org]] - Full Title: Mariner 1 - Wikipedia - URL: https://en.wikipedia.org/wiki/Mariner_1 ## Highlights **Mariner 1, built to conduct the first American planetary flyby of Venus, was the first spacecraft of NASA's interplanetary Mariner program. Developed by Jet Propulsion Laboratory, and originally planned to be a purpose-built probe launched summer 1962** --- **Mariner 1 was launched** by an Atlas-Agena rocket from Cape Canaveral's Pad 12 **on 22 July 1962**. **Shortly after liftoff, errors in communication between the rocket and its ground-based guidance systems caused the rocket to veer off course, and it had to be destroyed by range safety. The errors were soon traced to the omission of a hyphen-shaped symbol from one of the guidance program characters. ==Science-fiction author Arthur C. Clarke described the error as "the most expensive hyphen in history"==.** --- The hand-written guidance equations contained the symbol "R" (for "radius"). This "R" should have had a line over it ("R-bar" or R̄), denoting smoothing or averaging of the track data coming from an earlier calculation. But **the bar was missing, and so the computer program based on those equations was incorrect. This was not an error in programming, but an error in the specification.** --- The loss of America's first interplanetary spacecraft constituted an **$18.5 million ($166 million in today's dollars) setback for NASA. The incident underscored the importance of a thorough pre-launch debugging of software** as well as a need to engineer programs such that minor errors could not cause catastrophic failures. ---