|astronautix.com||Mercury Space Suit|
|Mercury Suit - Mercury suit. Note parachute pack, only worn on first flight.|
Credit: NASA. 15,254 bytes. 144 x 443 pixels.
The Mercury spacesuit was a custom-fitted, modified version of the Goodrich U.S. Navy Mark IV high altitude jet aircraft pressure suit. 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).
Purchase approval in the amount of $125,000 was requested by the Space Task Group from NASA Headquarters for the procurement of five developmental pressure suits for Project Mercury.
A pressure suit compatibility evaluation in the Mercury spacecraft mock-up was performed in suits submitted by the David Clark Company, B. F. Goodrich Company, and International Latex Company. Four subjects participated in the tests.
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 suit procurement program was divided into two phases: Phase I, operational research suits which could be used for astronaut training, system evaluation, and further suit development; and Phase II, Mercury pressure suits in the final configuration.
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.
The astronauts were fitted with pressure suits and indoctrinated as to use at the B. F. Goodrich Company, Akron, Ohio.
Wearing the Mercury pressure suits, the astronauts were familiarized with the expected reentry heat pulse at the Navy Aircrew Equipment Laboratory, Philadelphia, Pennsylvania.
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.
Flight-type pressure suits were received from the B. F. Goodrich Company and were immediately used on the human centrifuge to assist in determining final adjustments that were necessary in preparation for manned space flight.
The third Mercury centrifuge training program was conducted for the astronauts at the Aviation Medical Acceleration Laboratory. This was considered the final major centrifuge training preparation for the first manned Mercury-Redstone flight. No difficulties were encountered; a decided improvement in the performance of 3-axis hand-controller tasks by the astronauts was noted. The Mercury-Redstone 3 (MR-3) flight activities were adhered to as closely as possible - actual spacecraft couches were used, a production hand-controller assembly was installed, the latest model pressure suits were worn, and the environmental control system was equipped with a freon coolant. Failures in spacecraft sequencing were introduced which required the astronaut to initiate an appropriate manual override.
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.
The B. F. Goodrich Company reported that it had successfully designed, fabricated, and tested a pivoted light attenuation tinted visor to be mounted on a government-issued Mercury helmet.
A number of improvements had been made to the Mercury pressure suit for the Mercury-Atlas 9 (MA-9) flight. These included a mechanical seal for the helmet, new gloves with an improved inner-liner and link netting between the inner and outer fabrics at the wrist, and an increased mobility torso section. The MA-9 boots were integrated with the suit to provide additional comfort for the longer mission, to reduce weight, and to provide an easier and shorter donning time. Another change relocated the life vest from the center of the chest to a pocket on the lower left leg. This modification removed the bulkiness from the front of the suit and provided for more comfort during the flight. These are but a few of the changes.