This week in rocket history: Mercury-Atlas 7.

Mercury-Atlas 7 was the seventh flight of Project Mercury, the U.S.’s first crewed spaceflight program, and in many ways, it was similar to the sixth flight, which was also the first American orbital flight.

Capsule Aurora 7 with astronaut Scott Carpenter launched from LC-14 at the Cape Canaveral Air Force Station on May 24, 1962. Five minutes later, he was in orbit, among the fastest crewed ascents ever.

Since this was NASA’s second-ever crewed orbital flight, Carpenter’s tasks were pretty simple. All he had to do was operate a few experiments and get back safely. The experiments included taking pictures from orbit, studying the behavior of liquids in weightlessness, and collecting data on the ionosphere. One phenomenon he studied, in particular, was mysterious clouds of particles near the spacecraft that reflected sunlight.

The nearly five hours in orbit went fine, but there were problems when Carpenter was to return. Some of the issues were because of mistakes he made, but others showed how skillful he was. Unlike Mercury-Atlas 6 with John Glenn, Carpenter was able to do more manual control of the spacecraft while in orbit. The reaction control system on the Mercury spacecraft had two separate tanks – one used by the automatic controls and the other during manual control. The significance of this will be apparent later.

This was originally planned as an experiment, but after one of the automatic systems malfunctioned, Carpenter had to take control for real. Part of the problem was that he was preoccupied looking at the mysterious particles and wasted manual control fuel in the first two orbits of his three-orbit mission. Because of this error, Carpenter had to conserve fuel by drifting through space uncontrolled during most of his last orbit.

When it came time to deorbit, the automatic system did not work properly, so Carpenter had to maintain attitude manually during the retro burn, which used more fuel than planned.

Finally, Carpenter was late initiating the deorbit burn to return him to Earth because he tried to fix the automatic system. After deorbit, he tried to resume manual control but was unable because the tank was empty. The automatic system mostly managed it, but its propellant was finally exhausted at about 21 kilometers altitude. Fortunately, the worst part of the reentry was over by then, and the capsule remained mostly in control, only swinging a few degrees beyond the ten-degree limit. However, the lack of fuel and the late start to the burn resulted in Aurora 7 landing 400 kilometers downrange from the planned landing site. And the automatic control system malfunction required Carpenter to manually deploy the parachutes at the right times.

The retrieval team took almost an hour longer than expected to find the capsule after it splashed down. While the recovery ship’s crew knew where Carpenter would land before he got there because of radar, they had to take the time to travel to where he splashed down.

The flight proved that the Mercury spacecraft was capable of supporting a human in space and returning them back to Earth safely. It also demonstrated that a human pilot could take control if needed. Future Mercury flights would be much longer – up to several days in space.

Carpenter was in good physical shape after the flight, but his career wasn’t. Chris Kraft, head of the NASA Astronaut Office, was not happy with Carpenter after he returned. In his opinion, Carpenter should not have wasted fuel looking at the mysterious particles. Carpenter never flew in space again and left NASA in 1964. He would return to NASA in 1967 to be the Executive Assistant to the Director of what is now called the Johnson Space Center after a brief stint in the Navy’s SEALAB project. One of the cool things he did while on SEALAB II was make the first phone call from the ocean floor to outer space, during the Gemini 5 mission.

Oh, and those mysterious clouds of particles around the capsule? Jettisoned urine that flash froze in space.

More Information

Flight of Aurora 7 (NASA)