Project Mercury Reviewed

The Wiesner task force on space had recommended that “a thorough and impartial appraisal of the MERCURY program should be urgently made.” Those managing the Mercury effort welcomed this suggestion, but for rea­sons different than those which had led the Weisner group to call Mercury “marginal.” The NASA team was confident that Mercury was a sound program, and feared that without the positive assessment they believed would result from such an independent review, President Kennedy might decide that even the suborbital mission planned in the next few months was too risky, and would not allow NASA to carry it out.

A first step was to inform the White House that there was a rehearsal flight for the suborbital mission, with a chimpanzee named Ham as its passenger, scheduled for January 31. After not hearing from anyone at the White House for several days after the inauguration, acting administrator Dryden was able on January 26 to meet with new science adviser Wiesner to let him know about the upcoming mission; Dryden wanted to make sure that President Kennedy “would not be surprised by reading about it in the morning paper.”32

Robert Gilruth, the head of the Space Task Group that was in charge of Project Mercury, suggested to George Low at NASA headquarters that NASA push for an early start on the review. Low agreed, and relayed the suggestion to Dryden.33 Then Dryden in early February met again with Wiesner, who agreed to charter an ad hoc panel of the President’s Science Advisory Committee (PSAC), again chaired by Donald Hornig of Princeton University, to conduct the review. Dryden met with Wiesner and Hornig on February 11 to discuss the composition of the panel. They agreed that the basic question the panel would address was: “Was Mercury ready to fly?”34

That question was also being debated within NASA. Originally the first suborbital flight with an astronaut in the spacecraft, Mercury-Redstone 3 (MR-3), had been scheduled for late March. But the January 31 flight with Ham aboard had landed 132 miles downrange from its target point and had subjected the chimp to a 14.7 g force on reentry, 3 g more than planned.35 These deviations from the flight plan were primarily the result of the overac­celeration of the Redstone launcher and early firing of the spacecraft escape rocket. Even after these problems, NASA managers at the Space Task Group and some at NASA headquarters were ready to commit an astronaut to the next flight. However, “key members of von Braun’s team quickly decided that they wanted another booster test before a man could fly,” and von Braun did not overrule them. This decision “likely cost the United States the distinction of putting the first human in space. . . NASA was more afraid of the consequences of an accident than those of coming in second.”36 On March 3 the first crew-carrying Mercury mission was postponed until late April. The extra Redstone flight was launched on March 24 and went well; from NASA’s point of view, there now was no obstacle to launching the first U. S. astronaut on a brief ride through the lower reaches of space.37

If the MR-3 mission had gone forward on its original schedule, the astro­naut aboard would have been not only the first American, but also the first human, to go into space, albeit not into Earth orbit. If this had happened, it is unlikely that the Soviet launch of Yuri Gagarin into orbit three weeks later would have had such a dramatic impact on U. S. space policy. But of course this was not known in March, and with the review of the PSAC panel not completed and given von Braun’s judgment that Mercury was not yet ready to fly with an astronaut aboard, it would have been difficult if not impossible for NASA to get White House permission to go ahead with the mission on its original schedule.

The ten-person Hornig panel spent four days in early March visiting the facilities at the McDonnell Corporation factory in St. Louis where the Mercury capsule was built; the launch facilities at Cape Canaveral, Florida; and the Space Task Group at NASA’s Langley Research Center in Hampton, Virginia. Science adviser Wiesner on March 7 thanked Hugh Dryden for the “thorough and candid presentation of all elements of the program,” and suggested that “this complete cooperation is evidence of a continuation of the excellent relationship” between NASA and the White House. This was a somewhat ironic suggestion, given the critical tone of the Wiesner task force two months earlier and the lack of preinaugural contact between the incom­ing administration and NASA. Dryden noted that as the result of the panel’s review, “certain members. . . who, previously, had no contact whatever with the program, changed their minds completely after they visited factories and the laboratories and saw what was going on and talked with the people car­rying on the work.”38

Although the panel had finished most of its work by mid-March, its report was not formally submitted to the White House until April 12. The reason for the delay was continuing reservations by a biomedical subgroup of the panel. The panel report concluded that the planned suborbital flight, which by then had slipped to early May, would be “a high risk undertaking but not higher than we are accustomed to taking in other ventures.” The report reviewed the accomplishments and failures of the Mercury program and assessed the risks involved and the probability of success. It noted that “the Mercury program has apparently been carried through with great care” and that “almost everything possible to assure the pilot’s survival seems to have been done.” The panel rated all aspects of the Mercury system as being more than 85 percent reliable except the booster and telemetry, which were rated 70 to 85 percent reliable. Even these items were “not per se a cause for alarm” for astronaut safety, just for mission success. The probability of the astronaut surviving the suborbital mission “appears to be around 90 to 95 percent although NASA estimates are somewhat higher.” The panel noted that “it was too early” to estimate similar probabilities for an orbital flight.39

The only serious reservations about the readiness of Mercury to launch an astronaut were expressed by the medical experts on the Hornig panel. They were worried about the fact that the astronaut’s blood pressure would not be monitored during flight and that high pulse rates such as those observed on Ham in the January flight, combined with the possibility of low blood pressure during the most stressful parts of the flight, could mean that the astronaut would be near collapse. NASA met with members of the medical panel on March 17 and then again on April 11 together with science adviser Wiesner, who shared the panel’s concerns, but were unable to allay their reservations. The experts suggested various additional tests prior to clearing MR-3 for launch, and particularly a high number of ground and flight tests with chimpanzees. Hugh Dryden thought that such a step was “totally unre­alistic” and Robert Gilruth facetiously suggested that if so many tests with chimpanzees were needed, the program ought to move to Africa. The panel’s final report worried that “it is not known whether the astronauts are likely to border on respiratory and circulatory collapse and shock, suffer a loss of con­sciousness or cerebral seizures, or be disabled from inadequate respiratory or heat control,” and that the degree of risk associated with the mission “is at present a matter for clinical impression and not for scientific projection.” Although no additional chimpanzee tests were added to the program, the three astronauts from whom the MR-3 pilot would be chosen did undergo additional runs at a Navy centrifuge in Johnstown, Pennsylvania, that simu­lated the stresses of reentry.40

On April 12, the same day on which the panel’s report was delivered to the White House, the Soviet Union launched Yuri Gagarin into Earth orbit, and Gagarin returned to Earth with no obvious ill effects. This feat made moot many of the concerns of the panel’s medical experts.