Editing Mariner 2 (section)

=== Launch ===
[[File:Mariner 2 launch.jpg|thumb|The launch of Mariner 2, on August 27, 1962.]]
[[File:Video-mariner-2-launch-020429.ogv|thumb|Mariner Atlas-Agena ignition]]
[[File:Animation of Mariner 2 trajectory.gif |thumb |right |Animation of Mariner 2{{'s}} trajectory from August 27, 1962, to December 31, 1962<br>{{legend2|magenta| Mariner 2}}{{·}}{{legend2| Lime |[[Venus]]}}{{·}}{{legend2| RoyalBlue|[[Earth]]}}]]

At 1:53 AM EST on August 27, Mariner 2 was launched from [[Cape Canaveral Air Force Station]] Launch Complex 12 at 06:53:14 UTC.{{r|report}}{{rp|97}}{{r|Neugebauer_Snyder}} The bug in the rocket’s software that resulted in the loss of Mariner 1 had not been identified at the time of the launch.{{r|Ulivi19}} In the event the bug caused no issues with the launch since it was in a section of code that was only used when the data-feed from the ground was interrupted and there were no such interruptions during the launch of Mariner 2.{{r|Ulivi19}}

The flight proceeded normally up to the point of the Agena booster engine cutoff, at which point the V-2 vernier engine lost pitch and yaw control. The vernier started oscillating and banging against its stops, resulting in a rapid roll of the launch vehicle that came close to threatening the integrity of the stack. At T+189 seconds, the rolling stopped and the launch continued without incident. The rolling motion of the Atlas resulted in ground guidance losing its lock on the booster and preventing any backup commands from being sent to counteract the roll. The incident was traced to a loose electrical connection in the vernier feedback transducer, which was pushed back into place by the centrifugal force of the roll, which also by fortunate coincidence left the Atlas only a few degrees off from where it started and within the range of the Agena's horizontal sensor. As a consequence of this episode, GD/A implemented improved fabrication of wiring harnesses and checkout procedures.

Five minutes after liftoff, the Atlas and Agena-Mariner separated, followed by the first Agena burn and second Agena burn. The Agena-Mariner separation injected the Mariner 2 spacecraft into a geocentric escape hyperbola at 26 minutes 3 seconds after liftoff. The NASA NDIF tracking station at Johannesburg, South Africa, acquired the spacecraft about 31 minutes after launch. Solar panel extension was completed approximately 44 minutes after launch. The Sun lock acquired the Sun about 18 minutes later. The high-gain antenna was extended to its acquisition angle of 72°. The output of the solar panels was slightly above the predicted value.

As all subsystems were performing normally, with the battery fully charged and the solar panels providing adequate power, the decision was made on August 29 to turn on cruise science experiments. On September 3, the Earth acquisition sequence was initiated, and Earth lock was established 29 minutes later.{{r|report}}{{rp|97–109}}