Mercury suit. Note parachute pack, only worn on first flight.
Status: operational 1960.
It consisted of an inner layer of Neoprene-coated nylon fabric and a restraint outer layer of aluminized nylon. Joint mobility at the elbow and knees was provided by simple fabric break lines sewn into the suit; but even with these break lines, it was difficult for a pilot to bend his arms or legs against the force of a pressurized suit. As an elbow or knee joint was bent, the suit joints folded in on themselves reducing suit internal volume and increasing pressure.
The Mercury suit was worn "soft" or unpressurized and served only as a backup for possible spacecraft cabin pressure loss - an event that never happened. Limited pressurized mobility would have been a minor inconvenience in the small Mercury spacecraft cabin. The Mark IV, Model 3, Type 1 suit from which it was derived featured various enhancements in fit and ease of donning, as well as substantially improved pressurization control. The original Mercury prototype suits were specially-reworked Mark IV suits (NASA designated them XN-1 through XN-4 models, but they were referred to by engineers as the "quick fix" suits).
The B. F. Goodrich Company was selected as the contractor to design and develop the Mercury astronaut pressure suit. Company technology in this field dated back to 1934, when it developed the first rubber stratosphere flying suit for attempts at setting altitude records.
The first manned development system tests were completed at the AiResearch Manufacturing Division, Garrett Corporation. Tests were conducted in the altitude chamber to determine proper functioning of all system valves and components. A McDonnell subject was clothed in a Mercury-type presure suit for these tests. Preliminary data from these tests indicated that the system functioned satisfactorily.
Between November 1959 and January 1960, 10 developmental Mercury full-pressure suits were delivered. These suits were used in various Mercury training and development programs. Several problem areas were denoted. One involved stretching which complicated the suit mobility problem. This matter was being investigated, and one of the solutions was felt to be undersizing to allow for a suit growth factor. In addition, modifications would have to be made in suit insulation to provide for better pilot mobility. These problems were to be expected in a developmental program.
The astronauts and medical personnel who had tested the developmental suits received in November 1959 recommended a number of changes to increase the physical mobility of the astronaut before the production effort began. Evaluation of the test suits with the suggested modifications indicated that the mobility and suit-spacecraft compatibility had been greatly enhanced. The stretching which once had been a problem area had been significantly decreased.
The subjects were clothed in pressure suits and subjected to postlanding conditions for 12 hours without serious physiological effects. The purpose of this test was to evaluate human tolerance, and the results indicated that no modification to the system were necessary. However, the postlanding ventilation conditions would continue to be monitored and requirements for any modifications would be evaluated.
Development of an advanced state-of-the-art pressure suit and helmet was started. This action was taken in preparation for the Mercury extended range or 1-day mission program. The objectives were aimed at improvements in unpressurized suit comfort, suit ventilation, pressure suit mobility, electrically heated helmet visor with additional light attenuation features, and the fabrication of a mechanical visor seal mechanism.
Tests were conducted with a subject wearing a Mercury pressure suit in a modified Mercury spacecraft couch equipped with a B-70 (Valkyrie) harness. When this harness appeared to offer advantages over the existing Mercury harness, plans were made for further evaluation in spacecraft tests.