ABMA initially began work by screening potential materials and methods, and testing these materials with jet burners. From this, they chose what seemed the  best. Four protective methods were explored: ablation, heat sink, radiation, and transpiration. Ablation proved promising, so an investigation of plastics, fibers,  and ceramics was started. To flight test the findings, three scaled-down models were constructed, and the first was flown on the IRBM demonstration flight in  September 1956. No recovery attempts were made, but, according to telemetry data, the model functioned well. Recovery efforts were scheduled for the Missile  Number 34 shot in May 1957; however, the mission was not fulfilled because the REDSTONE booster failed. Missile Number 40, fired in August, was completely  successful, and the nose cone was recovered close to the predicted impact range of 1,100 nm. Other shots were unnecessary, and the scaled-model tests were  concluded. The ablation principle had been proven 66 . ABMA now began to work toward the full-scale nose cone re-entry Missile AM-5 launched on 18 May 1958 registered a re-entry success. Recovery of the  full- scale nose cone in good condition by the Navy marked a significant step forward in the state-of-the-art of this nation's long-range missile  development programs. Also interesting was the fact that re-entry was visible to on-site observers. This was followed by a July firing—Missile AM-6—and  recovery. The most famous of the re-entry tests, however, was JUPITER Missile AM- 18 fired on 18 May 1959. Contained within the nose cone were two  primates, designated Able and Baker, that survived their flight in excellent condition. Thus, not only was ABMA's ablative theory ably demonstrated, but  life could pass through outer space and be safely brought back to the earth 67 .  _____________________________

66. Rpt, Re-Entry Studies, 25 Nov 58, Vol I. 67. Ibid, Vol II.