S61-02740 (5 May 1961) --- Astronaut <a href="https://en.wikipedia.org/wiki/Alan_Shepard" class="extiw" title="en:Alan Shepard">Alan B. Shepard Jr.</a> has his heart rate checked prior to his <a href="https://en.wikipedia.org/wiki/Mercury-Redstone_3" class="extiw" title="en:Mercury-Redstone 3">Mercury-Redstone 3 (MR-3)</a> mission, the first American manned suborbital spaceflight. The attending physician is Dr. William K. Douglas. Photo credit: NASA or National Aeronautics and Space Administration
NASA
1961-05-05
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