Mariner 1 Date: 07.22.1962 This was to be the first Mariner mission. It was intended to perform a Venus flyby.
The vehicle was destroyed by the Range Safety Officer 293 seconds after launch at 09:26:16 UT when it veered off course. The booster had performed satisfactorily until an unscheduled yaw-lift (northeast) maneuver was detected by the range safety officer. Faulty application of the guidance commands made steering impossible and were directing the spacecraft towards a crash, possibly in the North Atlantic shipping lanes or in an inhabited area.
The destruct command was sent 6 seconds before separation, after which the launch vehicle could not have been destroyed. The radio transponder continued to transmit signals for 64 seconds after the destruct command had been sent.
The failure was apparently caused by a combination of two factors. Improper operation of the Atlas airborne beacon equipment resulted in a loss of the rate signal from the vehicle for a prolonged period. The airborne beacon used for obtaining rate data was inoperative for four periods ranging from 1.5 to 61 seconds in duration. Additionally, the Mariner 1 Post Flight Review Board determined that the omission of a hyphen in coded computer instructions in the data-editing program allowed transmission of incorrect guidance signals to the spacecraft.
During the periods the airborne beacon was inoperative the omission of the hyphen in the data-editing program caused the computer to incorrectly accept the sweep frequency of the ground receiver as it sought the vehicle beacon signal and combined this data with the tracking data sent to the remaining guidance computation. This caused the computer to swing automatically into a series of unnecessary course corrections with erroneous steering commands which finally threw the spacecraft off course.
