In 1962, during the second manned orbital Mercury flight, a series of problems developed, and the United States came close to losing an astronaut in space. And, many in NASA felt, it was the astronaut’s own fault.
Scott Carpenter was not supposed to fly the Mercury-Atlas 7 mission. Scheduled for May 1962, just three months after John Glenn became the first American to orbit the Earth, the MA-7 mission was intended to essentially repeat Glenn’s flight, three orbits with some additional experiments added. Astronaut Donald “Deke” Slayton was scheduled to fly the mission. But just five weeks before launch, Slayton was diagnosed with a faint heart murmur during a routine physical. It did not impose a serious health risk, but it was enough for NASA to revoke Slayton’s flight status and remove him from the mission. It was assumed that Slayton’s backup, Wally Schirra, would take over. But because Schirra was generally considered to be the most technologically apt of the Mercury Seven astronauts, NASA decided to save him for one of the more challenging later missions, and instead assigned Scott Carpenter to take over Slayton’s flight. Carpenter had been Glenn’s backup.
Scott Carpenter was not a fighter pilot, which, in the testosterone-soaked world of the Mercury astronaut corps, put him lower in the pecking order. NASA’s trainers considered him to be the least technically-skilled of the astronauts. He also had a reputation as an artsy visionary who would wax poetic about the beauty of spaceflight, which he promptly reinforced by naming his new space capsule “Aurora Seven”–representing, he said, “the dawn of a new age”. It did not endear him to NASA’s hardnosed engineers.
After Glenn’s successful flight, NASA scientists began to pile on experiments for the next mission, designed to test the capabilities of both the Mercury spaceship and its pilot. One experiment called for the astronaut to release a multi-colored balloon to determine his ability to see colors and judge distance in space. Another called for a period of “upside-down” flying to test its affect on the pilot’s balance and orientation. There would also be some experiments to study the behavior of liquids in zero-G, and an attempt to see some bright flare signals on the Earth’s surface. Slayton had resisted all these additions, arguing that he already had enough things to do, but Carpenter did not have the same pull within NASA that Slayton did, so they all got added to the flight plan. It would be a busy mission.
Although it was carefully concealed from the public, there was a bitter conflict raging within the Mercury space program, between the astronauts and the engineers. The astronauts were all military test pilots; they operated in a culture where the pilot had complete control of his ship, and made the flight decisions. To the NASA engineers, however, the spaceship was basically just a payload, which could be fully automated and controlled from the ground. The astronaut, in their view, was little more than a passenger. Heck, a chimpanzee could–and did–fly Mercury missions. This clash of basic philosophies would come to a bitter breaking point with Aurora Seven.
The initial launch of Aurora Seven, at 7:45am on May 24, 1962, went smoothly as the Atlas booster put Carpenter into orbit. But already there was a problem, though it wasn’t immediately recognized. One of the gyroscopes in the capsule’s automatic control system was malfunctioning–its measurements of pitch (the up-and-down orientation of the spacecraft) were off by about twenty degrees. The control system then tried constantly to correct the orientation but was unable to because of the inaccurate measurements–and this used up fuel.
Because of the busy flight schedule, Carpenter did not notice the gyroscope problem. But now he himself began adding to the fuel problem. The Mercury craft had two separate hydrogen peroxide fuel systems, one for the automatic control system, and one for the manual system. The astronaut could take control of the ship using a “fly-by-wire” joystick. But, if he forgot to switch off the automatic system, his maneuvers would then draw fuel from both systems. And with many maneuvers, the fly-by-wire system would fire some of the larger thrusters to make the move, often overshooting and requiring yet another maneuver to compensate.
And Scott Carpenter was making a lot of maneuvers. In addition to a running commentary to the ground describing the beautiful views of clouds and stars that he was seeing, Carpenter was turning the nose of his spacecraft this way and that to take a lot of photographs.
The combination of the malfunctioning gyroscope and all the maneuvering drained Aurora Seven’s fuel quickly. After just one 90-minute orbit, the peroxide supply in the automatic system was down to 51 percent. This was potentially serious. In order to land safely and accurately, the Mercury capsule had to be held in a constant 34-degree pitch during re-entry, and that required about 40 percent of the automatic system’s fuel. Flight Director Chris Kraft now noticed that Aurora Seven was using fuel far too rapidly, and radioed Carpenter to ask him to start conserving to make sure he had enough for re-entry. On board the spacecraft, a “low fuel” warning light also appeared on the control panel; Carpenter covered it over with a piece of tape so it wouldn’t distract him.
On his second orbit, Carpenter continued to carry out the scheduled experiments–but he also continued to maneuver around for better views. It wasn’t until the third and final orbit, while preparing for re-entry, that Carpenter saw that the automatic control system was being fed inaccurate information, and had been using up fuel to try to correct itself. By now, the hydrogen peroxide supply in the automatic system was already below 40 percent. There was now no choice; Carpenter would have to switch off the automatic system and manually orient and hold the proper re-entry position. But by the time re-entry arrived, the automatic system held only 20 percent fuel and the manual system a mere 5 percent. Now things were deadly serious. There was enough fuel to orient the capsule for the first portion of re-entry, but not through all of it. If Aurora Seven began to tumble, Carpenter would not be able to control it. The spacecraft would burn up in the atmosphere.
Fortunately, Aurora Seven held steady long enough to safely re-enter. But the entry had been made at an incorrect angle, which caused it to overshoot the intended splashdown point by some 250 miles. For a time, NASA didn’t known where Scott Carpenter was, or even if he was still alive. Once radio contact was re-established, it took three hours for a recovery ship to reach him. They found Carpenter happily floating in the Caribbean next to his spaceship in a raft, where he nonchalantly offered the rescue divers some food from his survival pack.
When the astronaut returned, however, he was no longer so nonchalant. NASA was furious with him. Although they publicly declared that the difficulties on the flight had been minor and had been the result of the gyroscope malfunction, privately they knew how close Carpenter had come to dying, and they blamed him for ignoring orders to conserve fuel and for using up most of his supply to take pictures of the pretty view. Carpenter was never given another flight assignment again, and soon left the astronaut program.
Privately, the other Mercury astronauts were also miffed with Carpenter. His misadventures had reinforced the engineers’ view that the astronauts could not be trusted to properly control the spaceship. The next scheduled mission was Wally Schirra’s Sigma Seven, and the astronauts, referring to Carpenter’s flight as “Stigma Seven”, were determined to repair the damage to their reputations. In the end, Schirra performed a flawless flight, staying in orbit twice as long as Glenn and Carpenter had, then landing almost spot-on at the splashdown site with more than 50 percent fuel remaining in both systems.
The Aurora Seven spaceship is now on display at the Museum of Science and Industry in Chicago.
Hidden History 
Nice post. It’s been so long since I read “The Right Stuff”, I can’t recall if Wolfe went into this much detail about Carpenter’s flight, but if he did, it had slipped from memory.