Mercury-Atlas 7

The Mercury-Atlas 7 (MA-7) mission took place on May 24, 1962. Five minutes after launch, Aurora 7 reached Earth orbit. Scott Carpenter conducted several experiments during his three orbits around the Earth. Among other things, he was supposed to observe flares that were fired in Australia, but this was not possible due to cloud cover.

An undetected malfunction in the automatic attitude control system, more precisely in the PHS (pitch horizon scanner), caused problems:

This led to significantly increased fuel consumption and was also responsible for Carpenter having to manually initiate and control re-entry. As a result of the incorrect attitude control, the capsule was misaligned by 25 degrees with respect to the yaw axis, so that the thrust was not in the correct direction, which resulted in a deviation of 270 km from the planned landing point. Insufficient thrust from the brake rockets caused a further 100 km deviation, and the ignition being delayed by a few seconds (as a result of manual activation) contributed a further 30 km. In total, Aurora 7 missed the expected landing point by 400 kilometers and fell outside the radio range of the recovery fleet.

About half an hour after splashdown, the first planes reached Carpenter, who was now waiting on a life raft next to the landing capsule. After three hours, he was brought aboard a helicopter that had taken off from the aircraft carrier USS Intrepid. The destroyer USS Farragut, which was first on the landing site, remained with the drop pod until it was recovered by the USS John R. Pierce six hours later.

NASA was completely satisfied with the rocket and spacecraft. The second Mercury flight with three orbits was also successful, so that consideration could now be given to extending the flight duration. The Soviet Union still held the record of 17 orbits of the Earth, a feat that the United States had not yet been able to match.

Carpenter’s in-flight performance, however, became the subject of controversy, primarily because of the excessive fuel consumption in orbit and the problems it caused during re-entry. Flight Director Christopher C. Kraft expressed anger at Carpenter for not following ground control instructions and paying too little attention to the instruments. Even at Kraft’s instigation, Carpenter was never again assigned to a space flight again.

Of course, the high fuel consumption was largely caused by the automatic attitude control system not working correctly. NASA’s internal post-flight analysis classified this malfunction as “mission critical” and credited Carpenter with responding adequately, thereby confirming that human pilots are capable of successfully compensating for the failure of automated systems.