Mercury-Redstone 3 - Preparation

Preparation

The Freedom 7 spacecraft, 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 6 March, rather than use an alternative capsule. The booster originally intended for the flight, Redstone #3, had been delivered to the Cape in early December; however, it was then used on the MR-1A test flight on 19 December. 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.

In late 1960, there had been a growing number of concerns about the standards of the Redstone launch vehicle; the MR-2 test flight, crewed by a chimpanzee, had had technical problems during the launch leading to the spacecraft flying too high, too far and too fast. As a result, the mission was two minutes longer than planned, and the re-entry subjected the passenger to 14.7g rather than the planned figure of approximately 12g. 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. 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. 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. The MR-BD flight was almost completely successful, ensuring that the crewed MR-3 flight could proceed without further significant delay.

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 as the primary pilot, with John Glenn and Gus Grissom 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 22 February without any indication as to which of the three was expected to fly the mission. 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. Glenn served as Shepard's backup on launch day, with Grissom focusing on training for MR-4, the next suborbital mission.

The initial launch attempt, on May 2, 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 5 May, with an expected launch time of 7:20 a.m. EST.