On October 29, 1961, three chimps and 12 medical specialists moved into their Cape quarters to join two other simians and eight persons already in flight preparation status. The name given to "Enos," the animal selected as the flight test subject, in Greek or Hebrew means "man," and the training and flight performance recorded by this chimpanzee proved the sobriquet to be well chosen. Captain Jerry Fineg, chief veterinarian for the mission, described Enos as "quite a cool guy and not the performing type at all." This "immigrant" from the French Cameroons had none of the tendencies of his circus-trained counterparts. Enos' backup "pilots," listed in order of their flight readiness ability, were "Duane," named for Duane Mitch, a veterinarian; "Jim," named for Major James Cook, of the same profession; "Rocky," named for a well-known pugilist (Graziano) because of his cauliflowered ear and pugnacious spirit;and "Ham," the astrochimp veteran. The ratings were made by Fineg and another Air Force officer, Marvin Grunzke. Fineg later learned that when these same chimps had gone through their earlier launch and reentry training on the centrifuge at the University of Southern California, they had been rated in the same order.46
The psychomotor equipment used by Enos on the MA-5 mission was more complicated than that operated by Ham during the Mercury-Redstone 2 suborbital flight. Housed in the cover of his pressurized couch, Enos' package was rigged to present a four-problem cycle. The first would last for about 12 minutes, and the second followed six minutes of rest. The routine would proceed until the  cycle was completed, then the four problems would be repeated until the mission ended. Problem one would offer right- and left-hand levers that Enos could use to turn off lights, avoiding a mild shock in the left foot (the same as for Ham). The second problem planned was a delayed-response experiment. Twenty seconds after a green light would appear on the panel, Enos would have to press a lever to receive a drink of water. Although there would be no penalty for his failure to respond, if the chimpanzee should pull the lever too early the problem would simply recycle and he would receive nothing. The third, a fixed-ratio problem, would involve pulling a lever exactly 50 times to receive a banana pellet. This would also be voluntary and without penalty. Chimpanzee intelligence would be tested in the fourth. Three symbols - circles, triangles, and squares - would appear in various two-of-a-kind combinations, with the task being to pull a lever under the odd symbol to avoid a mild shock. Lack of response during rest periods would give the indication that the animal was well oriented to his spacecraft environment.47
Planning for this second trial of the Mercury worldwide tracking network was elaborate. Supporting the MA-5 mission were 18 stations, plus the Goddard Space Flight Center and the Mercury Control Center. Goddard and the Control Center furnished computer support and management of the overall operation, respectively.
|Mercury Control Center||Launch|
|Cape Canaveral (AMR)||Launch|
|Grand Bahama Island (AMR)||Downrange tracking|
|Grand Turk||Downrange tracking|
|Atlantic Ocean Ship||Remote tracking|
|Canary Islands||Remote tracking|
|Kano, Nigeria||Remote tracking|
|Zanzibar, Africa||Remote tracking|
|Indian Ocean Ship||Remote tracking|
|Woomera, Australia||Remote tracking|
|Point Arguello, California||Command|
|White Sands, New Mexico||Remote tracking|
|Corpus Christi, Texas||Remote tracking|
|Eglin Air Force Base, Florida||Remote tracking|
|Goddard Space Flight Center, Maryland||Computing and communications|
 Seventy-three key people assigned to the various stations received their final mission briefing on October 23. Once again the tracking teams included several Mercury astronauts. Shepard was assigned to Bermuda, Schirra to Australia, Slayton to Guaymas, and Cooper to Point Arguello, while at the Cape, Carpenter had a station in the blockhouse, Grissom was the capsule communicator in the Mercury Control Center, and Glenn served as backup capsule communicator in the center.49
45 "Mission Directive for MA-5." Before his arrival at the Cape, Enos had received 1,263 hours of training over a 16-month period, including 343 hours under restraint. Results of the Project Mercury Ballistic and Orbital Chimpanzee Flights, NASA SP-39 (Washington, 1963), 39.
46 Norman E. Stingely and John D. Mosely, "MA-5 Operations," in Results of the Mercury Chimpanzee Flights, 35; Jerry Fineg, interview, Holloman AFB, Sept. 15 and 25, 1964; Huntsville (Ala.) Times, Nov. 29, 1961; Washington Evening Star, Dec. 1, 1961; New York Times, Nov. 30, 1961; Houston Chronicle, Nov. 12, 1961. The intelligence of these chimpanzees was remarkable. One of their training tasks was to pull a lever exactly 50 times, and for his accuracy the animal received a reward of a banana pellet. More or less than 50 pulls caused the training unit to recycle without giving any reward. Stanley C. White of MSC medical operations told a reporter that the chimps would pull the lever "bangity-bangity-bang" about 45 times, then carefully pull Nos. 46, 47, 48, and 49, and finally make pull No. 50 with one hand cupped under the dispenser to receive the reward. (Washington Evening Star, Nov. 28, 1961.) In a training test at Holloman a chimp working on a flashing-light problem pulled levers 7,000 times in 70 minutes, making only 28 errors. Kenneth F. Weaver, "School for Space Monkeys," in "Countdown for Space," National Geographic, reprinted from the May 1961 magazine, 727. Also see article in Aerospace, XXXIV (March 1963).
47 "Postlaunch Memorandum Report for Mercury-Atlas No. 5."
48 "MA-5 Data Acquisition Plan," NASA/ STG, Oct. 20, 1961.
49 "Mercury Personnel Man Worldwide Tracking Sites During MA-5 Mission," anon., NASA/STG, undated; "Status Report No. 12"; "MA-5 Plan," anon., undated.