The Central Intelligence Agency and Overhead Reconnaissance; the U-2 and Oxcart Programs, 1954-1974

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Secret NOFORN
Chapter 2
64

The early models of these MC-2 and MC-3 partial-pressure suits were very uncomfortable for the pilots. To prevent loss of pressure, the heavy coverall had to fit tightly at the wrists and ankles (in the early models of these suits, the feet were not included in the pressurization scheme). The pilot had to wear gloves and a heavy helmet that tended to chafe his neck and shoulders and was prone to fogging. Problems with the pilot life-support system were believed to have been the cause of several early crashes of the U-2.

Having gotten a pilot into this bulky suit and shoehorned him into his seat in the cockpit, the next problem was how to get him out in an emergency. The U-2 cockpit was very small, and the early models did not have an ejection seat. Even after an ejection seat was installed, pilots were reluctant to use it because they were afraid they would lose their legs below the knees when they were blown out of the cockpit. To save weight, the first pilot's seat was extremely simple with no height adjustment mechanism. Designed for pilots of above-average height, the seat could be adjusted for shorter pilots by inserting wooden blocks beneath the seat to raise it. In later versions of the aircraft, Kelly Johnson added a fully adjustable seat. $ ^{35} $

The Air Force undertook bailout experiments at high altitudes from balloons in the autumn of 1955 to determine if the suit designed for the U-2 pilot would also protect him during his parachute descent once he was separated from the life-support mechanisms inside the aircraft. To avoid getting the "bends" during such descents or during the long flights, pilots had to don their pressure suits and begin breathing oxygen at least 90 minutes before takeoff so that their bodies would have time to dissipate nitrogen. This procedure was known as prebreathing. Once the pilots were in their suits, eating and drinking became a major problem, as did urination. The first model of the pressure suit, used by Lockheed test pilots, made no provision for urination. A subsequent model required the pilot to be catheterized before donning his flying suit. This method of permitting urination during flight proved very uncomfortable and, by the autumn of 1955, was replaced with an external bladder arrangement that made the catheter unnecessary. To reduce elimination, pilots ate a low-bulk, high-protein diet on the day before and the morning of each mission.