In retrospect Kuettner has generalized about the problem of "Man-Rating Space Carrier Vehicles" in terms relating his experience with both aviation and missile technologies:
While it is admittedly an oversimplification, the difference between the two technologies may be stated in the following general terms. From an aviation standpoint, man is not only the subject of transportation, and as such in need of protection as a passenger; but he is also a most important integral part of the machine over which he truly has control. His decisions in expected and unexpected situations are probably the greatest contributions to his own safety. Aviation, to the best of our knowledge, has never seen the necessity for a fully automatic initiation of emergency escape.In the spring of 1959, while Kuettner was still signing himself the "Adam-NASA Project Engineer," he and his deputy, Earl M. Butler, began a series of triangular conferences, with Kurt H. Debus and Emil P. Bertram of ABMA's Missile Firing Laboratory at the Cape, in one corner, and Charles Mathews and Jerome B. Hammack, the Mercury-Redstone project engineer for STG, in the Langley corner. Between these informal discussions and six formal study panels inaugurated by von Braun, a consensus was supposed to arise on, among other things, the sort of emergency detection system necessary to warn of impending cataclysms in the booster and to trigger some sort of automatic ejection. Preliminary agreements on a design for an abort or safety system began early in good accord. But the uncertain reliability program, booster recovery proposal, capsule design changes, and electrical interface problems fouled the subsequent development of the Redstone abort-sensing system.9 In this respect the Atlas was more nearly ready than the Redstone by the end of the year.
In contrast, rocket technology has been for 20 years a missile technology governed by the requirements of target accuracy and maximum range. As such, it had to develop automatic controls. Unlike a human payload, a warhead has no use except on the target. Once the missile fails, it may as well destroy itself during flight. (For this reason, missilery has accepted aerodynamically unstable vehicles which, in case of loss of thrust, flip over and break apart,  destroying themselves in the air.) There has been no need to save the payload after a successful flight or in case of a catastrophe.
The development of manned space flight is not just a matter of replacing a warhead by a manned cabin. Suddenly, a switch is thrown between two parallel tracks, those of missile technology and those of aviation technology, and an attempt is made to move the precious human payload from one track to the other. As in all last-minute switchings, one has to be careful to assure that no derailment takes place.8
Many factors contributed to the slippage in the Mercury-Redstone schedule, but one significant cause for delay grew out of a subtle difference between ABMA and STG in their approach to pilot safety and reliability. The role of the astronaut was clearly at issue here longer than anywhere else. Conditioned by their designs for Project Adam, the Huntsville rocketmen thought of the astronaut throughout 1959 as merely an "occupant" or "passenger." The Adam proposal for an escape system during off-the-pad aborts would have ejected a biopack capsule laterally into a tank of water alongside the launch pad. Having less trust than STG in the reliability of "Old Reliable," the Redstone engineers insisted on putting safety first and making it fully automatic wherever possible. Reliability, they insisted, is only a concept and should be secondary to safety. This attitude was illustrated in the introductory paragraphs of the ABMA proposal for the Redstone emergency detection system. The author, Fred W. Brandner, began by saying that the use of missiles for transporting man would demand an automatic escape system to assure pilot safety:
This system has to rely on emergency sensors. There are an enormous number of missile components which may conceivably fail. Obviously, it would be impractical and actually unsafe to clutter up the missile with emergency sensors. However, many malfunctions will lead to identical results, and, in sensing these results and selecting the proper quantities, one can reduce the number of sensors to a few basic types.10 Brandner proposed to measure only three basic quantities: the control system attitude and angular velocity, the 60-volt control and 28-volt general electrical power supplies, and the chamber pressure of the propulsion system. To ensure "a high degree of passenger (pilot) safety" on the Mercury-Redstone rocket, if operational limits set on these sensors should ever be exceeded the capsule would eject from the booster and be lowered by parachute.
Brandner's modest proposal stated the issue but not the solution to the general question of man-machine relationships in Project Mercury. In 1959 the technical debate was still inextricably mixed up with previous attitudes toward the precise role of man in a manned satellite. Could the pilot test the vehicle or should the vehicle test the pilot? Mercury was NASA's program and STG's responsibility, but at this stage of development the military establishment and missile industries still knew, or thought they knew, more about the technological path for man's first climb into space than NASA-STG did.11
 From the Pentagon, for example, Brigadier General Homer A. Boushey, Director of Advanced Technology for the Air Force, had predicted in January that the most important key to space flight in the next decade would be not simply manned but rather piloted spacecraft:
By piloted spacecraft, I refer to a vehicle wherein the pilot operates controls and directs the vehicle. This is quite a different concept from the so-called man-in-space proposal which merely takes a human "along for the ride" to permit observation of his reactions and assess his capabilities. The high-speed flight experience of the NACA and the Air Force has shown that piloted craft return research data more effectively and more economically than do unmanned vehicles. While there is a place, certainly, for automatic, instrumented vehicles, I believe man himself will prove "the essential payload" to the full utilization of space. Orbital rendezvous, controlled landing after reentry, and space missions other than the simplest sensing and reporting type, will require man. If for no other reason than that of reliability, man will more than pay his way.12Boushey's percipient remarks illustrated the persistent residue of misunderstanding remaining from interagency competition for the manned satellite project in the pre-NASA, pre-Mercury period. Task Group officials felt compelled to defend the distinctive nature of Mercury and to emphasize that NASA astronauts were never intended to be passive passengers. Rather, they were to prove their full potential as pilots, within limits prescribed by the mission requirements programmed into the automatic systems. Although there were long and hard arguments within STG as to whether man should be considered "in the loop" or "out of the loop" in performing various tasks, the preponderance of NACA-bred aeronautical engineers in STG usually voted for as active an astronaut as possible.
Outside pressures from scientists and missile engineers also helped unify and consolidate opinion within STG. The distinguished research chief of Bell Telephone Laboratories and one of the fathers of communication satellites, John R. Pierce, summed up the argument for automation: "All we need to louse things up completely is a skilled space pilot with his hands itching for the controls."13
The problem of man-rating the Atlas was preoccupying another task force of still larger proportions than the one concerned with the Redstone. The industrial and military engineers in southern California and at the Cape who were trying to make the Atlas meet its design specifications could and did mobilize more resources than either STG or ABMA could command. A few individuals stood out as leaders in the vast effort. Kuettner's counterpart for the AirForce was Bernhard A. Hohmann, another former test pilot at Peenemuende West, who had been project engineer on the first two models of the Messerschmitt-163, one of the first rocket-powered aircraft. In August 1959, Major General Osmond J. Ritland of the Air Force Ballistic Missile Division (BMD) assigned him the job of supervising the systems engineering at Space Technology Laboratories (STL) for a pilot safety and reliability program on the Mercury-Atlas series. As Brandner did for the Redstone, D. Richard White, an STL electronics engineer,  made the preliminary designs for the Atlas emergency detection system. White was inspired, he said, "one Sunday in May when I imagined myself sitting atop that bird." Edward B. Doll, STL's Atlas project manager, could never imagine anyone foolish enough to sit on an Atlas, but he allowed Hohmann and White to proceed with their commitments.14 STL performed an overall technical direction over the associate contractors for the Atlas similar to that performed by STG for NASA, but with significant differences. STL had not been involved in the original MX-774 design behind the Atlas, and although it became closely associated with conceptual development of Atlas as a weapon, ultimate responsibility remained with the Air Force Ballistic Missile Division. Both STL and STG were systems engineering organizations, but STG had a deeper background in research and was directly responsible for the development of the project it managed; STL had broader experience in systems engineering, missile development, and business management.
Hohmann and his assistant, Ernst R. Letsch, huddled closely with the reliability statisticians at STL, led by Harry R. Powell, and with BMD's Mercury project liaison officer, Lieutenant Colonel Robert H. Brundin, also appointed by Ritland in August 1959. But the main responsibility for detail design, development, and production work fell on the shoulders of the manufacturers, General Dynamics (formerly Convair)/Astronautics (GD/A or CV/A) of San Diego. The details, tooling, and implementation of the emergency detection or abort sensing system for the Atlas were guided by Charles E. Wilson, Tom E. Heinsheimer, and Frank Wendzel. Their boss, Philip E. Culbertson, the Mercury project manager for General Dynamics/Astronautics, conferred repeatedly and sometimes heatedly with Hohmann, Brundin, Doll, and his own factory production engineers, John Hopman, Gus Grossaint, Frank B. Kemper, and R. W. Keehn.15
Here, too, a triangular dialogue was going on during initial considerations for man-rating the Atlas. But STG engineers were far away, busy with other matters, and knew well how little they knew about the Atlas. NASA and the Air Force, like STG and the Army, informally had agreed to divide developmental responsibility and labor at the capsule-separation point in the trajectory. So STG was not directly involved in the tripartite workings of the so-called "BMD-STL-GD/A complex" in southern California.
Looking at Project Mercury from the West Coast in 1959 gave a set of very different perspectives on the prospects for accomplishing the program on time and in style. South of Los Angeles International Airport there was no consensus and precious little communication of the confidence felt across the continent on the coast of Virginia. But STL, Convair, and Air Force representatives at the Cape gradually diffused some of the contagious enthusiasm of STG while commuting between home and field operations. More important still, the sense of desperate military urgency to develop an operational ICBM still pervaded the factories and offices devoted to the Atlas in southern California. Motivation already mobilized might easily be transferred if only the Atlas could be proved by the end  of the year. STG was more sanguine about this forthcoming proof than the Atlas people, and NASA Headquarters seemed even more optimistic.
Perhaps symbolic of the profound Air Force distrust of the "bare Atlas" approach and indicative of lingering doubts about the competence of the STG neophytes who had stolen the march on man in space was the acronymic name imposed by Air Force officers on the abort sensing system. White and Wilson wanted to call it simply the Atlas "abort sensing system." No, someone in authority insisted, let's make the name more appropriate to STG's plans to use the Atlas "as is."16 So this play on words, "Abort Sensing and Implementation System," became the designator for the only part of the Atlas created solely for the purpose of man-rating that missile. Reliability was truly designed into the "ASIS"; once this component was proven and installed, the Atlas ICBM should, it was hoped, be electromechanically transformed into the Mercury-Atlas launch vehicle.
 Astronaut Donald K. Slayton defended his prospective role and STG's stance on the issue of automation when he addressed his brethren in the Society of Experimental Test Pilots on October 9. By his own admission, these were some "stubborn, frank" words:
First, I would like to establish the requirement for the pilot.... Objections to the pilot range from the engineer, who semi-seriously notes that all problems of Mercury would be tremendously simplified if we didn't have to worry about the bloody astronaut, to the military man who wonders whether a college-trained chimpanzee or the village idiot might not do as well in space as an experienced test pilot. The latter is associating Mercury with the Air Force MISS or Army Adam programs which were essentially man in a barrel approaches. The answer to the engineer is obvious and simple. If you eliminate the astronaut, you can see man has no place in space. This answer doesn't satisfy the military skeptic, however, since he is not questioning the concept of a man in space but rather what type man. I hate to hear anyone contend that present day pilots have no place in the space age and that non-pilots can perform the space mission effectively. If this were true, the aircraft driver could count himself among the dinosaurs not too many years hence.Slayton's defense of Mercury before his professional colleagues outside NASA was echoed time and again in the next two years by NASA spokesmen. But many critics remained skeptical because it was obvious that Mercury was being designed to fly first without man. Flight controllers and electronics engineers who had specialized in ground control of supersonic interceptors and who had confidence in the reliability of remote control of automatic weapon systems were the least enthusiastic about allowing the pilots to have manual overrides. Christopher C. Kraft, Jr., the chief flight director for STG, preceded Slayton on the same program at the meeting of the experimental test pilots. He reviewed the range network to be provided and the operational plan to be used for the Mercury orbital mission. At that time, Kraft circumspectly avoided any public indication of his personal views on the role the astronaut would play, but years later he confessed his bias:
Not only a pilot, but a highly trained experimental test pilot is desirable . . . as in any scientific endeavor the individual who can collect maximum valid data in minimum time under adverse circumstances is highly desirable. The one group of men highly trained and experienced in operating, observing, and analyzing airborne vehicles is the body of experimental test pilots represented here today. Selection of any one for initial space flights who is not qualified to be a member of this organization would be equivalent to selecting a new flying school graduate for the first flight on the B-70, as an example. Too much is involved and the expense is too great.17
The real knowledge of Mercury lies in the change of the basic philosophy of the program. At the beginning, the capabilities of Man were not known, so the systems had to be designed to function automatically. But with the addition of Man to the loop, this philosophy changed 180 degrees since primary success of the mission depended on man backing up automatic equipment that could fail.18 In public, the managers of NASA and of Mercury, who had to request funds and justify their actions before Congress and the people, appeared as optimistic as possible and pointed out what could be achieved with successful missions. Privately, they not only had doubts, they cultivated a group of professional pessimists whose job it was to consider every conceivable malevolent contingency. John P. Mayer, Carl R. Huss, and Howard W. Tindall, Jr., first led STG's Mission Analysis Branch and set a precedent for spending ten times as much effort on planning for abnormal missions as for normal ones.19
Although not always obvious to STG, there also were differences in attitudes within the space medicine fraternity. Since mid-1958, men like Siegfried J. Gerathewohl and George R. Steinkamp had led the school of thought that believed that man was more nearly machine-rated than machines were man-rated. Conversely, the chief of the space medicine division of the Air Force's School of Aviation Medicine, Colonel Paul A. Campbell, influentially asserted his belief that "in these past two or three years the situation has suddenly changed, and the machine capability has advanced far beyond man's capability."20 Other biologists and medical college specialists also had doubts about the peculiar combination of stresses - from high to zero to high g loads - that the man in Mercury must endure. Whatever the majority medical opinion might have been, the Task Group felt itself beleaguered by bioastronautical specialists who wanted to "animal-rate" the spaceflight machines all the way from amoebas through primates before risking a man's life in orbit.
8 Joachim P. Kuettner, "Manrating Space Carrier Vehicles," in Ernst Stuhlinger et al., eds., From Peenemünde to Outer Space: Commemorating the Fiftieth Birthday of Wernher von Braun (Huntsville, Ala., 1962), 629-630. See also "Biographic Sketch: Dr. Joachim P. Kuettner," Marshall Space Flight Center, May 1, 1963; Kuettner, interview, Huntsville, April 28, 1964.
9 Memo, Kuettner to "all labs," Development Operations Division, Army Ballistic Missile Agency, "Mercury-Adam Project," Jan. 14, 1959; Kuettner, "Mercury Project," draft status report, May 21, 1959. Cf. typescript prospectus, Kuettner, "ABMA's Participation in the Mercury Project," undated [about Aug. 1959]. See also memo, A. Richard Felix to Dir., Aeroballistics Lab., "Visit to NASA, Langley Concerning Future Wind Tunnel Tests of the Jupiter-C Boosted Manned Space Capsule," Jan. 15, 1959; and Mack W. Shettles, "Status Report - Project Mercury," ABMA report No. DFE-IN-09-59, Feb. 13, 1959. Cf. memo, Dieter Grau to "M-G&C-DIR," "Unsatisfactory Condition on MR Abort Sensing System," Oct. 11, 1960.
10 F. W. Brandner, "Proposal for Mercury–Redstone Automatic Inflight Abort Sensing System," Army Ballistic Missile Agency report No. DG-TR-7-59, Redstone Arsenal, June 5, 1959, 1.
11 See, for example, letter, James D. Sams to CO, ABMA, "Project Mercury-Redstone Delineation of Responsibility," Oct. 8, 1959; memo, C. J. Kronauer, to Capt (?) Hombaker, "Project Mercury Schedule Notification," Oct. 12, 1959; Debus to Kuettner, "NASA-ABMA-AFMTC Project Mercury Operating Agreement," Nov. 9, 1959; letter, Gen. John B. Medaris to Yates, Dec. 10, 1959; Yates to Medaris, Dec. 21, 1959.
12 Brig. Gen. Homer A. Boushey in The Next Ten Years in Space, 30.
13 John R. Pierce quoted sympathetically by Carl Dreher, "Pie in the Sky: Scramble for the Space Dollar," The Nation, CXC (Feb. 13, 1960), 133. Such extreme positions were denounced by at least one independent engineer, viewing the man-in-space program in the October issue of the trade journal Automatic Control. For reprint, see George K. Arthur, "Why Man in Space? - An Engineer's View," in Richard M. Skinner and William Leavitt, eds., Speaking of Space: The Best from Space Digest (Boston, 1962), 142.
14 Bernhard A. Hohmann, interviews, El Segundo, Calif., Aug. 25, 1964, and Houston, Sept. 16, 1965; E. B. Doll, telephonic interview, El Segundo, Aug. 25, 1964; D. R. White, interview, Houston, Aug. 10, 1964. For an overview of the business evolution from Thompson Ramo Wooldridge into Space Technology Laboratories and Aerospace Corporation see Robert Sheehan, "Thompson Ramo Wooldridge: Two Wings in Space," Fortune, LXVII (Feb. 1963), 95-99, 139-146. See also House Committee on Government Operations, 87 Cong., 1 sess., Air Force Ballistic Missile Management (Formation of Aerospace Corporation), report No. 324, May 1, 1961.
15 See [Henry B. Kucheman, Jr.] "Reference File, AFBMD Support, Project Mercury," bound folder of documents, Air Force Space Systems Div., El Segundo, Calif., Jan. 4, 1961; Frank Wendzel and R. W. Keehn, interviews, San Diego, Calif., Aug. 28, 1964. For a description of advances in manufacturing techniques, see Richard Sweeny, "Atlas Generates Fabrication Advances," Aviation Week, LXXII (Jan. 4, 1960), 38-49. For an overview of the actors within the BMD-STL-GD/A complex, see transcript, "Proceedings of the Mercury-Atlas Booster Reliability Workshop," GD/A, San Diego, Calif., July 12, 1963, passim.
16 White interview; Philip E. Culbertson, comments, Aug. 16, 1965. Cf. Convair/Astronautics Report No. AZM-27-321, "Test Equipment for Abort Sensing and Implementation System for Mercury Atlas Flight," July 17, 1959.
17 Donald K. Slayton, speech, annual meeting, Soc. of Experimental Test Pilots, Los Angeles, Oct. 9, 1959.
18 Christopher C. Kraft, Jr., "A Review of Knowledge Acquired from the first Manned Satellite Program," MSC fact sheet No. 206, 1.
19 John P. Mayer and Carl R. Huss, "Trajectory Analysis," in Mercury Project Summary, Including Results of the Fourth Manned Orbital Flight, May 15 and 16, 1963, NASA SP-45 (Washington, 1963), 119; John M. Eggleston, "Some Abort Techniques and Procedures for Manned Spacecraft," Aerospace Engineering, XXI (Nov. 1962), 17.
20 Paul A. Campbell, "Man in Space - Where We Stand," Air Force and Space Digest, (July 1959), reprinted as Part 3 of Appendix B in Senate Committee on Aeronautical and Space Sciences, 86 Cong., 1 sess. (1959), report No. 1014, Project Mercury: Man-in-Space Program of the National Aeronautics and Space Administration. Cf. Siegfried J. Gerathewohl and George R. Steinkamp, "Human Factors Requirements for Putting a Man in Space," paper, ninth International Astronautical Congress, Amsterdam, Aug. 1958.