Mariner 1

Occurred 62 years ago




July 22, 1962





What was Mariner 1?

America's first attempt to explore Venus up close was lost to a software glitch. Investigators found a typo caused a fault in the launch vehicle's guidance software. The spacecraft and booster were destroyed shortly after launch for safety.

United States of America
Venus Flyby
P-37 / Mariner R-1
Spacecraft Mass
447 pounds (202.8 kilograms)
Spacecraft Power
Mission Design and Management
Launch Vehicle
Atlas Agena B (Atlas Agena B no. 5 / Atlas D no. 145 / Agena B no. 6901)
Launch Date
July 22, 1962 / 09:21:23 UT
Launch Site
Cape Canaveral Fla. / Launch Complex 12
Scientific Instruments
1. Microwave Radiometer
2. Infrared Radiometer
3. Fluxgate Magnetometer
4. Cosmic Dust Detector
5. Solar Plasma Spectrometer
6. Energetic Particle Detectors
7. Ionization Chamber
Two engineers in white lab boats inspect the Mariner 1 spacecraft. The spacecraft is about twice as tall as the men.
Mariner 1 in the spacecraft assembly facility on May 2, 1962 at NASA's Jet Propulsion Laboratory.


Mariner 1 was the first of two spacecraft NASA designed to send to Venus. Each carried a modest suite (about 20 pounds or 9 kilograms) of scientific instrumentation but had no imaging capability.

The spacecraft included 54,000 components and were designed to maintain contact with Earth for about 15 weeks.

Mariner 1 lifted off on July 22, 1962, but its rocket veered off course and the Range Safety Officer had to send a destruct command to the vehicle at T+294.5 seconds.

The failure was traced to a guidance antenna on the Atlas. Also, a software error, the omission of an overbar for the symbol R for radius (R instead of R̅) in an equation, caused the program to not respond as planned. It should be noted the omission was not a hyphen, as sometimes erroneously reported.

Engineers quickly fixed the problems and sent Mariner 2 on its way to Venus on Aug. 27, 1962. It completed the first

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