Mercury-Redstone BD (Booster Development) was an unmanned booster development flight in the U.S. Mercury program, launched on March 24, 1961, from Launch Complex 5 at Cape Canaveral, Florida. It used a boilerplate Mercury spacecraft and Redstone MRLV-5. Following the issues encountered during the MR-2 mission with Ham the chimpanzee, it became clear that the Redstone booster required further development before it could carry a human. Dr. Wernher von Braun added Mercury-Redstone BD to the launch schedule between MR-2 and MR-3.
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| Mercury Redstone Booster Development flight launch cover with Goldcraft cachet, postmarked Port Canaveral, March 24, 1961. |
The flight used a boilerplate spacecraft with an inert escape rocket and lacked a retro package or posigrade rockets. The MR-BD mission lasted eight minutes and 23 seconds, reaching an apogee of 113.5 miles (182.7 km) and a range of 307 miles (494 km). The spacecraft hit a peak velocity of 5,123 mph (8,245 km/h) and experienced a maximum load of 11 g (108 m/s²). The Redstone rocket and the boilerplate spacecraft were not intended to separate and impacted the ocean together 307 miles downrange, slightly short of the target. They sank to the ocean floor after detonating a sofar bomb. Despite some vibration issues in the adapter area, the booster performance was excellent.
