Mariner 1
An illustration of the Mariner spacecraft as it would appear in interplanetary space. Credit: NASA/JPL-Caltech
Completed 60 years ago
America's first attempt to explore Venus up close was lost to a software glitch. 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 is erroneously reported. The out-of-control spacecraft and booster were destroyed for safety.
| Mission Type Venus Flyby |
Duration 5 minutes |
| Launch July 22, 1962 06:53:14 UT |
Destroyed by Range Safety July 22, 1962 T+294.5 seconds |
Overview: Mariner 1
In formulating a series of early scientific missions to Venus in early 1961, NASA originally planned two missions, P-37 and P-38, to be launched on Atlas Centaur rockets, with each spacecraft weighing about 1,246 pounds (565 kilograms).
By the time NASA formally approved the plan in September 1961, problems with the Atlas Centaur necessitated a switch to the Atlas Agena B with a reduced payload.
By late spring 1962, engineers at NASA's Jet Propulsion Laboratory (JPL), had built two flight-ready spacecraft and one spare, and had shipped the flight units to the Cape Canaveral Air Force Station (now Cape Canaveral Space Force Station) in Florida to prepare them for launch. The 56-day launch window extended from July 18 to Sept. 12.
The three spacecraft were based on the design of the Ranger probes to the Moon (therefore named Mariner R). 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 2,500 hours – an ambitious goal given that the Ranger was designed for only 65 hours of contact.
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 remote encounter with another planet on Dec. 14, 1962, returning valuable information about our celestial neighbor.
Spacecraft and Technology
| Nation | United States of America (USA) |
| Objective(s) | Venus Flyby |
| Spacecraft | P-37 / Mariner R-1 |
| Spacecraft Mass | 447 pounds (202.8 kilograms) |
| Mission Design and Management | NASA / JPL |
| Launch Vehicle | Atlas Agena B (Atlas Agena B no. 5 / Atlas D no. 145 / Agena B no. 6901) |
| Launch Date and Time | July 22, 1962 / 09:21:23 UT |
| Launch Site | Cape Canaveral Fla. / Launch Complex 12 |
| Scientific Instruments |
|
Key Sources
Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.
