Whether the limit switches at the clamp rings below or above the spacecraft were at fault, or whatever improper rigging, wiring, or voltage regulation was the cause, it was exceedingly hard to rationalize that something was learned from this flight failure. Spacecraft and booster continued on their arc 10 miles high and 13 miles out to sea before being mangled on impact 2 minutes later. Salvage operations in water 72 feet deep recovered 60 percent of the booster but only 40 percent of the capsule.68 Extensive tests on the clamp-ring problem were conducted on rocket sleds at the Naval Ordnance Test Station at Inyokern, California.
For well over a year Holloman Air Force Base personnel, led by Major John D. Mosely,  of the Aeromedical Field Laboratory, had prepared a packaged payload with a medium-sized chimpanzee to ride the LJ-5 qualification flight. As late as mid-July 1960, operational planning still included a first-order test objective to determine the effects of a simulated Atlas abort acceleration on a chimp. The delay in capsule delivery and a large number of checkout difficulties encountered in late August, especially with the booster-capsule clamp rings and pyrotechnics, led William Bland and Rodney G. Rose to persuade Gilruth to rule out the primate on Little Joe 5. Besides that, the second Mercury-Redstone now being groomed for a chimp flight represented a direct conflict in scheduling.
As disappointing as this decision was to aeromedical personnel, including James P. Henry, the physician who supervised the animal program for STG, the managers of the Task Group felt they could not afford to risk further delays. The structural integrity of McDonnell's Mercury capsule and the escape system during that most critical time in the region of highest dynamic pressure had to be demonstrated as soon as possible. By deliberately omitting the environmental control system and its problems, the Task Group had hoped to concentrate on hardware dynamics, taking extraordinary precautions "to minimize premature firing of any of the capsule pyrotechnics on the launching pad."69 Obviously something - no one knew what - had been overlooked.
After the dismal failure of Little Joe 5, these bleak days for Project Mercury became even bleaker with the discovery that the helium leak in the capsule for MR-1 could not be fixed quickly; it would require the replacement of certain valves and the whole hydrogen peroxide tank. Furthermore a change in the MR-1 wiring was dictated by the poor sequence and circuitry design on Little Joe 5. NASA had one more Little Joe test booster on hand. One more airframe, the last one in existence, had recently been ordered as a backup to the next shot. On November 10, NASA Headquarters was reassured that a stripped capsule on the backup booster could fulfill the Little Joe 5 mission, "an essential one before manned flight," probably before the end of January. And both Mercury- Redstone 2 and Mercury-Atlas 2 still were considered "not beyond the realm of possibility" for launchings in December.70
There was precious little in Mercury to be thankful for during the Thanksgiving season of 1960, but there was more than enough work to keep everyone in STG preoccupied. Caldwell C. Johnson wrote Faget a summary memo concerning the capsule's weight growth and its effect upon Atlas performance and mission profiles. While McDonnell was conducting extensive tests of the impact skirt situation, Johnson and others were worried about whether it would ever work. In the light of later developments, the ferment over redesign at this time became significant, and Johnson's words grew in significance:
We have been monitoring Mercury weight growth, McDonnell's airplane-weight history and the X-15 weight versus development phase and conclude that Mercury orbit weight by the time of manned flight will exceed 3,000 pounds! Capsule weight during parachute opening mode will be 2,600 pounds;  flotation weight is practically as great. These increases have a detrimental effect upon orbital insertion probability, retrograde action, parachute opening loads, and water stability. The only single action that will cure the problem is weight reduction in the capsule but its weight growth is inexorable. It appears that several separate actions are necessary.
J. Mayer calculates that at 3,000 pounds the probability of orbit insertion is less than 96 percent even when based upon certain Atlas performance increases. Furthermore, the possibility of an African landing from an early abort is very real. He says there are some reasons to believe that Atlas weight can be further reduced and greater payload capacity realized but so far this is but speculation, and, in any case, doesn't do much for the African landing situation.
Some time ago increased retrograde capability was proposed but could not be justified at that time. There is little doubt that such a change is justified now - the question is whether posigrade impulse should likewise be increased to aid orbit insertion. It is tempting to combine posigrade and retrograde systems and to utilize the propellant as required by the particular flight situation. But, this is a rather drastic change.71
68 "Project Mercury Flight Test Report for Little Joe Mission No. 5 (capsule No. 3)," NASA Project Mercury working paper No. 166, Dec. 23, 1960; letter, Williams to R/A F. V. H. Hilles, Dec. 14, 1960; memo, Low for Administrator, "Report on Little Joe No. 5 and Mercury Redstone No. 1," Nov. 10, 1960. See also Fisher, comments, Sept. 15, 1965.
69 Memo, North to Dir., Space Flight Programs, "Project Mercury PMP Charts," Sept. 21, 1960, explains why the chimp was eliminated from LJ-5. John C. Palmer, "Test Directive for Little Joe V," approved countdown procedures, undated. See also minutes, "Little Joe V AeroMedical Operations Review Meeting," Richard S. Johnston, secretary, July 12, 1960; "Mission Document for Little Joe No. 5 (Capsule No. 3)," NASA Project Mercury working paper No. 121, May 25, 1960.
70 Low memo, Nov. 10, 1960; memo, Low to Asst. Administrator for Congressional Relations, "Mercury Redstone and Little Joe 5 Launchings," Nov. 16, 1960. The additional Little Joe airframe was suggested by Silverstein. Memos, William M. Bland, Jr., to Faget, "Visit of representatives of NAA-MD to STG," Feb. 1, 1960, and "Further Development of Little Joe Booster," Feb. 8, 1960; North to Silverstein, "Request for Approval Project Mercury Funding," June 27, 1960; Silverstein to Budget Office, "Budget on Approval of Project Mercury Funding," June 29, 1960. Cf. memo, C. J. Donlan to LRC Procurement Officer, "Contract NAS 9-59, Refurbished Little Joe Static Booster, Expedited Delivery," Nov. 16, 1960.
71 Memo, Johnson to Faget, "Mercury Weight Growth - Effect upon Orbit Insertion Probability, Retrograde Maneuver, Parachute Loads, and Flotation," Nov. 22, 1960, 1-3. Johnson speculated on possibilities:
"The really interesting scheme requires starting all over. Consider six (6) Pioneer or Explorer second stage motors clustered together as a posigrade-retrograde power pack. . . .
"On the subject of parachutes and weights: it is quite likely that the impact skirt system and its associated 100 pounds of weight could be eliminated if the capsule impact attitude could be restricted to 'pilot feet first' and without much swing. The main difficulty now is the pilot's low tolerance to lateral acceleration. . . . This is not a proposal but it's worth thinking of."
See also Huss comments.