***

            It’s March 24, 1961. And a Mercury-Redstone is being counted down at Cape Canaveral’s Pad 5.

            It’s March 24, 1961, and Alan Shepard is watching keenly.  The count continues smoothly. 

            It could be the day the first human flies in space.  But only if NASA tossed caution into the wind, caution creeping through some government ranks after Mercury-Redstone (MR) – 2, on January 31, the suborbital ride of Ham the chimpanzee that turned into a wild ride.

            The new Kennedy administration is worried about a failure.  Wernher von Braun also is cautious.  NASA’s top management echoes their caution.  Even though the Space Task Group in charge of Mercury — people like Walt Williams and Christopher Kraft — argued that the problems were minor, easily corrected, that we were ready to launch a man in space.

            It’s March 24 and this could be Shepard’s launch. Only it isn’t.  The Redstone is live, but the capsule is a dummy.  

            We’re counting down not to Shepard’s MR-3, but something inserted into the schedule carrying no number, just the designation MR-BD:  BD for Booster Development, a mission to test the fixes made to the Redstone.  

            Ham’s rocket had fired hot — an over-thrust that gulped fuel, caused the rocket to loft higher than planned and gulp propellants that ran out prematurely.  NASA engineers traced the over-thrust upstream from the engine to the thrust regulator that powered the fuel pumps and in effect served as a throttle.  It was modified so that it could not jam in the full-open position.   The abort system was modified so that it could not trigger an automatic abort in the final seconds of flight.   The MR-2 booster had experienced excessive vibrations in it’s upper body in the area of the instrument unit.  Four support struts and 210-lbs. of insulation were added to this area.

            As its name implied, MR-BD was strictly a booster show — carrying a “boilerplate” mock capsule, weighted and balanced like a real Mercury capsule.  The boilerplate Mercury had already flown in January 1960 in an abort test.  The Redstone, #7, had been designated for a third manned suborbital flight later in 1961.

            After a perfect countdown, looking, on the outside, like the Mercury/Redstone that could have carried Alan Shepard, MR-BD lifted off from its ring-like launch pedestal at 12:30 a.m.  Engine performance and flight profile traced a near-perfect plot, the same a manned Mercury flight would take.  Except no effort was made to cut the dummy capsule from the booster.  The Redstone’s engine cutoff hit the mark as planned — at 141.7 seconds.  The vehicle soared to the planned altitude of 115 miles and 8 min. 23 second splashed into the Atlantic 307 miles downrange, less than five miles from the target.  

            The flight satisfied von Braun’s requirements to fully qualify the Redstone.  And NASA sets launch date of April 25 for the first manned flight. 

            *

            The next day, the Soviet Union launches one one of its heavy Sputniks, Korabl-Sputnik-5, carrying a dog and a cosmonaut mannequin nicknamed Ivan Ivanovich.   It duplicates the one-orbit flight of Korabl-Sputnik -4, which also successfully carried a dog on March9.   Two successes in a row — the table is set for the first human in space.