The Mercury staff in October 1963 briefed the scientific community on its evaluation of the Mercury program.⁸  Aeromedical develop considerations were discussed in detail by the staff of the Manned Spacecraft Center, and will be only briefly summarized here.  Medical Operations involved medical maintenance and preflight preparation, medical monitoring, analysis, physiological responses to space flight, and recovery operations.

Medical maintenance for the astronauts had included routine medical care, together with annual and special physical examinations.  Preflight physical examinations were given for two purposes:  To allow the flight surgeon to state that the astronaut was qualified and ready for flight; and to provide a baseline for any changes resulting from exposure to the space-flight environment.  Early in the program, 10 days before the scheduled mission, the given a thorough evaluation.  This was performed by a Department of Defense team of medical specialists providing the specialties of internal medicine, ophthalmology, neurology, psychiatry, and laboratory medicine.  These specialties continued to be represented in later flights, although certain modifications were made as experience demonstrated the lack of serious effects of flight on the astronaut.  Three days prior to the flight a detailed physical examination was completed by the various medical specialists with necessary laboratory work.

On the morning of the flight, a brief medical examination was made to determine the readiness of the astronaut.  On the last two missions, MA-8 and MA-9, participation was reduced to that  of the flight crew surgeon only.

The postflight medical examinations were made initially by Department of Defense recovery physicians stationed aboard the were recovery vessel, but as the flights were lengthened and experience the accumulated, the pattern here too was modified.  On the early missions, the astronaut was flown to Grand Turk Island where he was joined by the team of medical specialists who had made the preflight examination and by the flight crew surgeon.  In the later, longer flights, when the recovery was made in the Pacific Ocean, NASA flight surgeons were predeployed aboard the recovery carrier to perform the initial postflight examination find debriefing.

Several valuable lessons were learned both with respect to the pattern of medical care provided and to policies relating to the astronaut.  In the first instance, it was learned early that there was need for many practice runs.  A medical countdown was developed with specific timing of events.  Also it was learned that backup personnel were needed, just as backups were needed for the various pieces of equipment, although the number must be kept at a minimum.
 
With reference to the individual astronaut, the medical profession learned many lessons from the flights.  For example, initially consideration had been given to isolating the flight crew so as to prevent development of a communicable disease immediately prior to flight.  This soon proved impractical, however, because the astronaut had too many last-minute activities.  Because of the relatively short period of the Mercury flight, no difficulty was experienced with a very modified isolation plan, although it was recognized that longer periods of flight in future missions might call for an evaluation of this problem.

Initially the. basic concept regarding drugs had been that they would b be made available for emergency use only.  Injectors made it possible for the, astronaut to self-administer drugs, through the residue pressure suit.  For the first, four missions these drugs included an for anodyne, an anti-motion- sickness drug, a stimulant, and a vaso-constrictor for treatment of shock.  In later missions these were reduced to the anti -motion-sickness drug and an anodyne (available both in the suit and in the survival kit) . For the last Mercury flight (MA-9), it was decided to make tablets of dextro-amphetamine sulfate available, both in the suit and in the survival kit, and medication was used for the first time during flight when the dextro-amphetamine sulfate was taken prior to the initiation of retrosequence.

Experience showed that care must be taken to prevent astronaut fatigue during the final preflight preparations as well as during postflight, activities.  Minimum time for postflight rest, and relaxation following a 34-hour mission was between 48 and 72 hours.

Dietary control was in force for approximately 1 week prior to each mission.  To prevent defecation during the mission, a low-residue diet was programmed for 3 days prior to launch, with the time extended if the launch was delayed.

In flight, food consisted of bite-size and semiliquid tube food on early missions, although on the MA-9 mission freeze-dehydrated food was added. The bite-size food caused problems by crumbling and some difficulty was encountered in hydrating the on the freeze-dehydrated food.

In the early missions urine was collected in a single container within the suit, but this device became unworkable as the mission time increased. Modifications of the suit made it, possible to collect five separate and complete samples, although the system would require modification for future missions.

No blood samples were obtained during flight, and every attempt was made to combine the various blood requirements so as to minimize the number of venipunctures, both preflight, and postflight.

8.  Mercury Project Summary Including Results of the Fourth Manned Orbital Flight, May 15 and 16, 1963, NASA SP-45, 1963.  This 444-page document provides the basis of the following summary which in many instances, is a synoptic version of the original document.  See particularly Charles A. Berry, ch. 11, "Aeromedical Preparations," pp. 199-209.