During the last week in February, therefore, the international space race seemed to have cooled. At home the reliability of the Redstone was very much at issue. It was at this juncture that the von Braun and Debus Mercury-Redstone teams presented to NASA Headquarters the results of three intensive reliability studies that they had made at Marshall since the overacceleration of MR-2 had given Ham such a rough ride. The first of these three separate probability studies was based on 69 Redstone and Jupiter flight histories; the second was based on a mathematical model using a reconstruction of the flight record of all components and subsystems of the Mercury-Redstone; and the third was a still more refined reliability study using adjusted values of the human factor and system design improvements. Together these studies yielded confidence figures that "led MSFC to opinion that the Mercury-Redstone launch vehicle reliability was in the range of 88 percent to 98 percent probability for launch success and crew survival, respectively."56 While President Kennedy, Defense Secretary Robert S. McNamara, and Administrator Webb were learning their executive empires and were instituting a thorough review of the Nation's space program, Dryden, Seamans, Silverstein, and Gilruth accepted von Braun's insistence to postpone the first manned flight and to insert an extra Redstone booster test into the Mercury flight schedule.57
Whereas the Space Task Group had been elated with the performance of Ham in spite of difficulties with the capsule and the booster on the MR-2 flight the last day in January, the von Braun team at Marshall and the Cape had undergone an anguished period of reappraisal during the first two weeks in February as they tried once again to explain the "chatter" in the guidance system of their Redstone rocket. On February 6, Debus recorded in his daily journal his position with respect to the readiness status of the booster to be used for the first manned flight: "At least one unmanned shot must be obtained with flawless performance of the Mercury-Redstone mission booster flight, or at least no major shortcoming must be discovered in the vehicle system." Eberhard F. M. Rees, von Braun's Deputy Director for Research and Development, concurred and so informed von Braun. The next day Kuettner drew up an elaborate memo for internal use in deciding what should be Marshall's technical recommendation on whether to man the next Mercury-Redstone flight. In a covering note,  Kuettner explained the situation to von Braun,58 and concluded that he personally would not advise calling a halt yet.
On Monday, February 13, 1961, Gilruth, Williams, Faget, Jerome B. Hammack, G. Merritt Preston, and Kenneth S. Kleinknecht of STG, along with John F. Yardley and R. L. Foster of McDonnell, met with the von Braun group at Huntsville to decide on "man or no man" for MR-3. By that date Debus had provided Kuettner with a list of 10 weak links, both in the hardware and in procedure, that needed correction before MR-3. The Marshall engineers incorporated their numerical guesswork into a "priority list of weak spots" that itemized seven major component problems, five minor component discrepancies, and six procedural difficulties still under study in mid-February.59
As Kuettner expected, political and medical considerations in the final decision to launch the first manned flight elevated the final choice to NASA Headquarters in Washington. Gilruth, his Redstone project engineer, Hammack, and the rest of STG were satisfied with the "quick fixes" made by Marshall and ground tested after MR-2. Certainly the seven astronauts felt impatiently ready to go. But von Braun and Debus reminded the Task Group of its own original ground rule for reliability: no manned flight would be undertaken until all parties responsible felt perfectly assured that everything was in readiness. Marshall engineers doubted that the difficulties encountered on the MR-1A and MR-2 missions would have endangered a human passenger. But they were committed to scrupulousness in their reliability program, too, and during the last week in February there were still seven significant modifications to the Redstone booster that seemed to require another unmanned flight test. So during this last week in February, Robert Seamans, Abe Silverstein, and Robert Gilruth acquiesced in the demands of Marshall Space Flight Center to insert one more Redstone flight into the Mercury schedule. The fateful decision was made to postpone MR-3, the first manned flight, until April 25 so something then called "MR-2A" could be inserted for a launch on March 28. On March 3 there seemed little question of the technical wisdom of this decision, although there was extreme sensitivity about the time set for the launch and about its possible public consequences.60
Marshall undertook to correct everything and asked STG only to provide the payload for the additional mission. Neither the Task Group nor McDonnell had an extra production capsule, so the boilerplate model that had been used on Little Joe-1B in January 1960 was refurbished and sent to Huntsville for the first mating with Redstone booster No. 5. Instead of the normal designation for the second try at an unfulfilled mission, MR-2A was renamed "MR-BD" (Mercury-Redstone Booster Development). Gilruth and company made no plans either to separate the capsule from the launch vehicle or to recover the remains. MR-BD was left primarily to von Braun and Debus, while STG turned most of its attention to Little Joe 5A. Only the operations team from STG would participate in manning the Control Center. As Marshall and the Cape made ready this flight  with the booster that had formerly been designated for the third manned suborbital training flight (MR-5), they were unaware that the Soviet Union was making ready another series of heavy Sputniks.61
On March 9, 1961, the U.S.S.R. announced it had launched into orbit its fourth cosmic ship, or Korabl Sputnik IV, weighing some 4,700 kilograms (10,364 pounds) and containing a dog passenger named Chernushka. When the dog was recovered, later that day, the Soviet recovery record suddenly became two out of four tries, and NASA saw the possible consequence of its MR-BD decision. Outside of NASA, the implications were by no means clear. The newspaper space race continued unabated.
In a highly publicized letter, Representative Overton Brooks wrote to President Kennedy on March 9, 1961, of his concern over military and trade journal reports that the space program might veer toward military control. Brooks thought the Wiesner report had implied this, and he knew of a special PSAC investigating committee of scientists, called the "Hornig panel" after its chairman, Donald F. Hornig. This group, charged with an overall review of the manned space program, had just finished spending the first four days of March traveling around investigating Project Mercury. Brooks reminded the new President that the intent of the Space Act of 1958 was to ensure that control of space research remain in civilian hands so that resulting information and technological applications would be open for the benefit of all enterprise, both private and public. Too much information would become classified, he said, if the military were preeminent in space research, development, and exploration. Brooks asked for and received Kennedy's reassurance that neither he nor Wiesner had considered subordinating NASA to the military.62
With Kennedy's affirmation of NASA's leadership role and its 10-year plan for space research, development, and exploration, Administrator Webb concentrated on the scientific criticisms and budgetary deficiencies of the agency. Program priorities and the funds necessary for them were taken up first. Webb found that most of his staff and field scientists were enthusiastic about getting on with advanced manned space exploration beyond Mercury. They wanted large booster development and manned spacecraft and space flight development leading to exploration of the Moon. Webb also learned that the scientific community outside of NASA was not so disenchanted with manned space flight as some had supposed. Lloyd V. Berkner, a geophysicist and chairman of the Space Science Board of the National Academy of Sciences, championed the cause of NASA programs. Berkner and Hugh Odishaw had just edited an anthology, Science in Space, attempting to garner the support of many disciplines for an expanded space program.63
On March 13 and 14, Administrator Webb and his chief lieutenants began a new series of annual presentations to Congress justifying their financial requests for the coming fiscal year 1962. Abe Silverstein, spurred several times by  Chairman Brooks of the House Committee on Science and Astronautics, departed from his prepared text on the progress of Mercury to explain the MR-BD decision in connection with the imminent first manned mission into space:
I don't know whether you heard our briefing here several weeks ago in which we pointed out that this Redstone booster traveled 400 miles out when it should have gone 293, and went to an altitude of about 150 miles, when it should have gone to 110. These were due to some booster malfunctions. We have tracked these down and we intend to go ahead and make changes in the booster so that we have better control of it. We are not about to operate with a booster that is as sloppy in performance as that.64Several days later in a speech before the American Astronautical Society, Administrator Webb publicly stated that NASA's program should be expanded to include more scientific space exploration.65 The effort of NASA management to get White House approval at this time for post-Mercury manned flight and basic funding for booster development was to prove of historical importance.66 On March 22, President Kennedy called Webb, Dryden, and Seamans to meet with himself, the Vice-President, and key White House staff to review the need for supplementing the NASA fiscal 1962 budget. As a result a $125.76 million increase was approved for NASA.67 In the mind of the general public, unaware of these deliberations on an accelerated space program, NASA was thoroughly identified with Project Mercury and attention was pointing toward the first manned mission in the near future.68
56 "The Mercury-Redstone Project," 5-37.
57 Ibid., 8-15. Before a press conference on February 8, 1961, President Kennedy had cautioned against a premature effort to "put a man in space in order to gain some prestige and have the man take a disproportionate risk." On February 28, Webb announced the President's order for a thorough review of the nation's space programs, and on March 2 a group from the President's Science Advisory Committee was already on tour and at the Atlantic Missile Range for a briefing on Project Mercury. See Aeronautical and Astronautical Events of 1961, 5, 8, 9.
58 Joachim P. Kuettner, note for Dr. von Braun, Feb. 7, 1961; memo, Kuettner to von Braun and others, Marshall Space Flight Center, "Recommendation to Space Task Group on Manned Mercury-Redstone Flight," Feb. 7, 1961; "Daily Journal," Launch Operations Directorate - Marshall Space Flight Center, Feb. 6, 1961.
59 Memo, Emil P. Bertram to Kurt H. Debus, "MSFC Meeting on MR-3 Manned Flight," Feb. 10, 1961; message, Debus to Kuettner, undated [about Feb. 12, 1961] re Launch Operations Directorate reply to Kuettner's memo of Feb. 7, 1961. See table 8-3 in Johnson et al., "The Mercury-Redstone Project," 8-15. The first priority list of weak "components" included the thrust controller, vibrations, cutoff arming timer, abort sensors, peroxide tank pressure regulator, peroxide system cleanliness, and a liquid oxygen manhole leak.
60 Memos, North to Dir., Space Flight Programs, "Mercury Status as of March 2, 1961," Mar. 3, 1961, 2, 3; Wernher von Braun to Marshall Space Flight Center, "Sensitivity of Mercury Launching Dates," March 3, 1961.
61 Message, Marshall Space Flight Center to STG, March 15, 1961; "Project Mercury Status Report No. 10 for Period Ending April 30, 1961," NASA/STG, 31; memo, Jerome B. Hammack, STG Cape Operations, to Project Dir., "Mercury-Redstone Booster Development Flight (MR-BD)," March 26, 1961.
62 Letters, Brooks to Kennedy, March 9, 1961; Kennedy to Brooks, March 23, 1961. See also Air Force replies to these and other charges in House Committee on Science and Astronautics, 87 Cong., 1 sess. (1961), Defense Space Interests, Hearings, March 17-23, 1961. Purser in his log for Gilruth, March 7, 1961, reported ushering the Hornig panel around Mercury sites from March 1 through 4: "All the comments I overheard were favorable. I also received very favorable direct comments from Dr. Hornig and the various panel members."
63 Lloyd V. Berkner and Hugh Odishaw, eds., Science in Space (New York, 1961). See Holmes, America on the Moon, 193-195. See also the special issue devoted to "Space Exploration in the Service of Science" of Bulletin of the Atomic Scientists, XVII (May-June 1961), 169-240.
64 House Committee on Science and Astronautics, 87 Cong., 1 sess. (1961), Hearings, 1962 NASA Authorization, Part I, testimony of Abe Silverstein, March 14, 1961, 77, 94, 99.
65 Luncheon talk by James E. Webb, NASA Administrator, to the American Astronautical Symposium, Washington, D.C., March 17, 1961.
66 The steps leading to the decision for an accelerated U.S. space program to include landing an American on the moon before 1970, as presented to the Congress on May 25, 1961, are to be detailed in subsequent NASA histories.
67 Senate Subcommittee of the Committee on Appropriations, 87 Cong., 1 sess. (1961), Independent Offices Appropriations, 1962, Hearings, testimony of Hugh L. Dryden, 642—643, 656.
68 See "The Expanded Space Program," Historical Sketch of NASA (EP-29), 27-35.