Mercury-Redstone 3, or Freedom 7, was the first United States human spaceflight, on May 5, 1961, piloted by astronaut Alan Shepard. It was the first crewed flight of Project Mercury. The project had the ultimate objective of putting an astronaut into orbit around the Earth and returning him safely. Shepard's mission was a 15-minute suborbital flight with the primary objective of demonstrating his ability to withstand the high g-forces of launch and atmospheric re-entry.
Shepard named his space capsule Freedom 7, setting a precedent for the remaining six Mercury astronauts naming their spacecraft and the format of their names. They selected names ending with a "7" in all the crewed Mercury spacecraft to commemorate the NASA's first group of seven astronauts.; the number 7 also was the model number for the McDonnell Model #7 space capsule used in the Mercury Program. His spacecraft reached an altitude of 101.2 nautical miles (116.5 statute miles, 187.5 km) and traveled a downrange distance of 263.1 nautical miles (302.8 statute miles, 487.3 km). It was the fourth Mercury flight launched with the Mercury-Redstone Launch Vehicle, from Cape Canaveral, Florida, close to the Atlantic Ocean.
During the flight, Shepard observed the Earth and tested the capsule's attitude control system, turning the capsule around to face its blunt heat shield forward for atmospheric re-entry. He also tested the retrorockets which would return later missions from orbit, though the capsule did not have enough energy to remain in orbit. After re-entry, the capsule landed by parachute on the North Atlantic Ocean off the Bahamas. Shepard and the capsule were picked up by helicopter and brought to U.S. Navy aircraft carrier USS Lake Champlain.
The mission was a technical success, though American pride in the accomplishment was dampened by the fact that just three weeks before, the Soviet Union had launched the first human in space, Yuri Gagarin, who completed one orbit on Vostok 1. In 2017 the first National Astronaut Day was held on May 5 to pay tribute to this first U.S. flight.
Preparation
The spacecraft for MR-3, Mercury capsule #7, was delivered to Cape Canaveral on December 9, 1960. It had originally been expected that a mission could be launched soon after the spacecraft was available, but Capsule #7 turned out to require extensive development and testing work before it was deemed safe for flight. However, as it had been earmarked since the summer as the first crewed spacecraft, the decision was taken to delay the mission until this particular capsule was ready, with a tentative launch date of March 6, rather than use an alternative capsule.This New Ocean, p. 342 The booster originally intended for the flight, Redstone #3,This New Ocean, p. 342 had been delivered to the Cape in early December;Grimwood, p. 118 however, it was then used on the MR-1A test flight on December 19.Grimwood, p. 119 The replacement, Redstone #7, did not arrive at the Cape until late March; by this time, however, the mission had already been postponed to await the results of another test flight.Grimwood, p. 129
In late 1960, there had been a growing number of concerns about the safety of the Redstone launch vehicle; the MR-2 test flight, carrying Ham the chimpanzee, had experienced technical problems during the launch, leading to the spacecraft flying too high, too far and too fast.This New Ocean, p. 315 As a result, the mission was two minutes longer than planned, and the re-entry subjected Ham to 14.7 g rather than the planned figure of approximately 12 g. The splashdown point was sixty miles from the nearest recovery ship, and it was over two and a half hours before a helicopter could recover the capsule and its passenger – by which time it had almost sunk.This New Ocean, p. 316 As a result, NASA was unwilling to launch the MR-3 mission without further development work; by late February, there were still seven major alterations they had made to the booster which required testing.This New Ocean, pp. 323–4 An additional testing flight was accordingly added to the schedule, MR-BD (for "Booster Development"; it was originally known as MR-2A). This would launch on March 28, pushing the MR-3 flight back a month to April 25.This New Ocean, p. 324 The MR-BD flight was almost completely successful, ensuring that the crewed MR-3 flight could proceed without further significant delay.This New Ocean, p. 330
The pilot for MR-3 had been chosen several months in advance, in early January, by the head of the program, Robert R. Gilruth. He had selected Alan Shepard (Navy) as the primary pilot, with John Glenn (Marine) and Gus Grissom (Air Force) as his backups; the other members of the Mercury Seven continued to train for later missions. The three names were announced to the press on February 22 without any indication as to which of the three was expected to fly the mission.This New Ocean, p. 342 Shepard's name was only announced publicly after the initial launch attempt had been canceled, as Gilruth wished to keep his options open in the event that last-minute personnel changes were required.This New Ocean, p. 350 Glenn served as Shepard's backup on launch day,This New Ocean, p. 351 with Grissom focusing on training for MR-4, the next suborbital mission.This New Ocean, p. 365
Naming Captain Shepard dubbed his capsule Freedom 7. Per Shepard, "Pilots have always named their planes. It's a tradition. It never occurred to me not to name the capsule." Shepard discussed the name with his wife, Louise, backup pilot John Glenn, and Robert R. Gilruth, and all liked it.
They selected names ending with a "7" to commemorate the seven astronauts, although some sources indicate the "7" a reference to Shepard's spacecraft being factory model no. 7. Thus, Shepard set a double precedent, both for naming the Mercury spacecraft at all, and for the common structure of their naming.
Flight The initial launch attempt, on May 2, 1961, was canceled due to weather problems two hours and 20 minutes before the launch time, with Shepard waiting in a hangar already suited and prepared. The flight was rescheduled for two days later, when it was delayed one more day due to inclement weather conditions, until May 5, 1961, with an expected launch time of 7:20 a.m. EST.This New Ocean, pp. 350–351
The countdown began at 8:30 p.m. the previous night, with Shepard waking up and eating a breakfast of steak and eggs with toast, coffee, and orange juice (the steak and eggs breakfast would soon become a tradition for astronauts the morning of a launch). He entered the spacecraft at 5:15 a.m. ET, just over two hours before the planned 7:20 launch time. At 7:05 a.m., the launch was held for an hour to let cloud cover clear – good visibility would be essential for photographs of the Earth – and fix a power supply unit; shortly after the count restarted, another hold was called in order to reboot a computer at Goddard Space Flight Center. The count was eventually resumed, after slightly over two and a half hours of unplanned holds, and continued with no further faults.This New Ocean, pp. 351–352 All of the delays resulted in Shepard lying on his back in the capsule for almost three hours, by which point he complained to the blockhouse crew that he had a severe need to urinate (because the mission would last under 20 minutes, nobody had thought to equip the Mercury with a urine collection device). The crew told him that this was impossible as they would have to set the White Room back up and waste considerable amounts of time removing the Mercury's heavily bolted hatch. An irate Shepard then announced that if he could not get out for a bathroom trip, he would simply urinate in his suit. When the blockhouse protested that that would short out the medical electrodes on his body, he told them to simply turn the power off. They complied, and Shepard emptied his bladder. Because of the position he was sitting in, the urine pooled somewhat underneath his back and with oxygen flowing through the spacesuit, he was soon dried out, and the countdown resumed. After the mission, the Mercury space suit was modified and a liquid waste collection device was installed.This New Ocean, p. 368
Mercury-Redstone 3 finally lifted off at 9:34 a.m. ET, watched by an estimated 45 million television viewers in the United States.This New Ocean, p. 341 Shepard was subjected to a maximum acceleration of 6.3 g just before the Redstone engine shut down, two minutes and 22 seconds after launch. Freedom 7's space-fixed velocity was , close to the planned value. Upon shutdown of the booster, the escape tower was jettisoned. Ten seconds later came capsule separation: the capsule detonated the explosive bolts on the Marman clamping ring that joined it to the booster and fired its posigrade rockets to gain distance. After capsule separation, the automated attitude control system (the Automatic Stabilization Control System, or ASCS) damped out any residual tumbling motions and then yawed Freedom 7 around 180 degrees, so the retrorockets would face forward ready for firing.The Mercury-Redstone Program, p. 15
Shepard now began testing manual control of the spacecraft's orientation. For redundancy purposes, the Mercury spacecraft's manual attitude control system used a different set of control jets than the automatic system and had its own fuel supply; when the system was activated, moving the three-axis control stick proportionally opened valves to the manual jets. The system could be selectively enabled on each axis, with ASCS automatically controlling the non-enabled axes. Shepard gradually assumed manual control, one axis at a time, leaving the remaining axes to ASCS. First he took manual control of pitch, reorienting the spacecraft from its "orbit attitude" of 14 degrees nose-down pitch to the retrofire attitude of 34 degrees nose-down pitch, then returning to orbit attitude. He then took manual control of yaw along with pitch, yawing the spacecraft to the left and then to the right to bring it back in line. Finally he assumed control of roll as well, testing it and then restoring the spacecraft's roll to normal. Once Shepard had taken control of all three axes, he found that the spacecraft's manual response was about the same as that of the Mercury simulator; however, he could not hear the jets firing, as he could on the ground, due to the levels of background noise.Results of the First U.S. Manned Suborbital Space Flight, pp. 71-72This New Ocean, p. 353
Shepard's next task was to make observations of the ground from the spacecraft's periscope, which extended through the "bottom" of the hull beneath his feet. Shepard's craft, an earlier version of the Mercury capsule, also had two small round viewing windows, one on each side, but the periscope was its primary means for observing. The periscope could be set either to a low-magnification wide-angle view or to a high-magnification narrow-angle view, and different optical filters could be inserted by turning a knob. During his long wait on the launch pad, Shepard had inserted a medium-gray filter in the periscope to cut down on sun glare, but he had not had time to undo this before launch. He found that when he tried to reach the filter knob to change it, the wrist of his spacesuit would bump the handle by his left hand that would manually activate the launch escape system. Even though the escape tower was long gone, Shepard gave up on trying to change the filter out of caution, leaving it in for the rest of the flight. Although the gray filter washed out colors, Shepard was still easily able to distinguish major land masses from clouds. He reported identifying major features such as the east coast of Florida, Lake Okeechobee, and Andros Island, the largest island of the Bahamas, but cloud cover made it difficult for him to make out other Bahamian islands.This New Ocean, pp. 353–5