any significant effect or prevent the satellite from reaching orbit, but this incident was thoroughly investigated because of the problems with MA-3--one modification to Mercury vehicles would involve removing the programmer's ability to reset itself in flight. Of continuing concern were rough combustion and gyroscope malfunctions as these failure modes had destroyed two Atlas E vehicles in June. The Spin Motor Rotation Detection System, invented to prevent an Atlas from launching with an improperly operating gyroscope, was just being phased in and would not appear in a Mercury vehicle until MA-5. The launch went extremely well and the thick-skinned Atlas survived Max Q acceleration. Capsule performance was also good despite some concern over high oxygen usage in orbit, but ground controllers did not consider it a serious problem and the oxygen supply was sufficient for at least 8 orbits. The process of turning the capsule around in orbit so its heat shield faced forward proved more difficult than expected, taking 50 seconds instead of the normal 20 seconds. At a few points during the mission, the capsule's attitude became slightly unstable due to the failure of two thrusters, which caused momentary telemetry dropouts. The capsule completed one orbit prior to returning to Earth. Reentry took place one hour and 28 minutes after launch, and splashdown occurred in the Atlantic Ocean 176 miles (283 kilometers) east of Bermuda. One hour and 22 minutes after splashdown the destroyer (which was 34 miles from the landing point) picked up the capsule, which was found to be in good condition with little damage from either liftoff, orbit, or reentry. Postflight examination found that the oxygen rate handle had been dislodged by liftoff-induced vibration and cracked open a valve. This had allowed oxygen to escape into space, but not at sufficient rates to trigger a telemetry warning measurement, although it did trigger the oxygen warning light in the capsule. The handle was redesigned afterwards to be more difficult to move. The problem reorienting the capsule after booster separation was found to be the result of an open circuit in the pitch gyro. The biggest problem encountered on MA-4 was an uncomfortably high level of liftoff vibration from T+5 to T+20 seconds, so a few more small modifications were made to the Atlas's autopilot. However, Manned Spaceflight Center director Bob Gilruth expressed his confidence that the booster was now man-rated, and that a human passenger would