In contrast to the rapid convergence of the orbiter designs, the booster studies fell into disarray. The initial points of reference lay in the Phase B booster concepts of McDonnell Douglas and North American Rockwell. Both contractors proposed vehicles somewhat larger than a Boeing 747, and weighing some five times as much when fueled. The North American concept had two dozen engines: 12 SSMEs and 12 jet engines, the latter serving during flyback to the launch site. McDonnell Douglas’s booster, only slightly less ambitious, was to use a dozen SSMEs as well, with ten turbojets.

The North American orbiter had featured a primary structure and skin of titanium, with tiles providing most of the thermal protection. The booster design was more eclectic. Its front section, which enclosed the crew compartment, had frames and skin of René 41, a nickel-chromium alloy that contained cobalt and molybdenum. Though it was strong and oxidation-resistant, it was hard to fabricate. Wings, vertical fin and canards, small forward-mounted winglets used for control, all were of titanium. The fuselage and its tankage were largely of aluminum.

Then came the thermal protection, which avoided the use of tiles in favor of hot structures. The designers might have simplified matters by specifying the wide use of tiles, as on the orbiter. Tiles, however, were in their infancy and North American had to show that it also understood the design of hot structures. As usual, bare titanium skin sufficed for the upper surfaces of the wings and fuselage. The underside, nose and forward fuselage, however, were a metallurgist’s delight — or nightmare. The wing leading edges would use coated columbium. Large surface areas would rely on the alloys René 41 and Haynes 188, which were exotic mixtures of nickel, cobalt, chromium, tungsten, and molybdenum. Because these metals would expand when hot, designers proposed to build the thermal protection in the form of shells, free to slide over the underlying structure. On paper, at least, the shells would not come loose.

Thermal protection on the North American booster. (North American Rockwell)

Such a design certainly was not in keeping with the preferences of Max Faget, who always sought the most conservative approach. It was an engineering efflorescence to match the economic efflorescence of the cost-benefit studies at Mathematica, and was likely to raise just as many eyebrows. Moreover, it showed that the exuberance of 1969, when Tom Paine wanted to go to Mars, was still alive. Much engineering experience is summed up in the acronym KISS: Keep It Simple, Stupid. This is what John Yardley’s designers had done at McDonnell Douglas, in crafting their own booster concept.

One can describe it succinctly: aluminum primary structure throughout, including wings, canards, and tail, with tiles of varying thickness to provide the thermal protection. Though metallic shingles would protect the leading edges, they would see use only in the limited areas where tiles would fail to suffice. [Brady and Clauser, Materials, pp. 241, 272; Lynch, Handbook, pp. 552, 822; Aviation Week: January 18, 1971, p. 37; June 7, 1971, pp. 55-61; AIAA Papers 71-804, 71-805; Reports LE 71-7, SD 71-114-1 (North American Rockwell); MDC E0308 (McDonnell Douglas)]

These design exercises gave both contractors the opportunity to conduct detailed investigations using a range of approaches: hot structures, aluminum and titanium primary structures, tiles, and metallic thermal protection. Neither contractor offered anything so simple as an aluminum orbiter protected with tiles, though McDonnell Douglas used this approach in its booster. Despite their complexities, however, the concepts were not obviously infeasible, and some people believed they could actually be built.

Along came the Grumman design studies, which put the orbiter’s liquid hydrogen in external tanks and lowered the booster’s staging velocity from 9750 to 7000 ft/sec. Boeing, which had built the first stage of the Saturn V, was teamed with Grumman and had responsibility for the booster. Its engineers determined that this reduction in velocity would bring a disproportionate reduction in the size and weight of the booster, which now would require much less propellant. In addition to this, the lower velocity meant that the booster would be much closer to the launch site when it released the orbiter and began its return. Being closer, it would need less fuel for its jet engines, further reducing its size. The upshot was that whereas the fully-reusable orbiter’s booster would have a dry weight of 798,500 pounds, the new orbiter would cut this booster weight to 494,900 pounds.

Better still, the lower staging velocity virtually eliminated the need for thermal protection. The booster now would need neither tiles nor exotic metals. Instead, it would use its structure as a heat sink, just as with the X-15. During reentry, it would experience a sharp but brief pulse of heat, which a conventional aircraft structure could accept and absorb without exceeding temperature limits. Hot areas would continue to demand a titanium hot structure, which would cover some one-eighth of the booster. The rest of this vehicle, however, would make considerable use of aluminum.

How could bare aluminum, without thermal protection, serve in a shuttle booster? It was common understanding that aluminum airframes would lose strength due to aerodynamic heating at speeds beyond Mach 2; higher speeds required titanium, with its greater temperature resistance. These principles, however, dealt with aircraft in cruise, which would face their temperatures continually. The Boeing booster would reenter at Mach 7. Its thermal environment, however, would resemble a fire that does not burn your hand when you whisk it through quickly. Across much of the underside, the vehicle would protect itself by the simple method of using metal with more than usual thickness, to cope with the heat. Even these areas would be limited, with the contractors noting that “the material gauges [thicknesses] required for strength exceed the minimum heat sink gauges over the majority of the vehicle.” [Report B35-43 RP-11 (Grumman); Aviation Week, July 12, 1971, pp. 36-39.]

In 1954, amid the early feasibility studies that led to the X-15, investigators found, to their pleasant surprise, that they could follow standard aircraft design practice in crafting this research airplane. As a bonus, they also discovered that its metal skin, designed for strength rather than for heat resistance, nevertheless would have enough thickness to serve effectively as a heat sink. Now, in 1971, engineers at Boeing were learning that their booster could offer the same bonus, while providing the convenience of aluminum, the most familiar of metals and the easiest to use.

When McDonnell Douglas went further, introducing an external-tank orbiter that lowered the staging velocity to 6200 ft/sec, its engineers designed a winged booster that was 82 percent aluminum heat sink. Though these designers could have lowered the staging velocity still further, by putting more propellant in the orbiter’s tanks, their selected configuration brought the largest savings in the weight of thermal protection. [Report MDC E0376-1 (McDonnell Douglas).]

Unfortunately, while the move to external tankage brought a welcome reduction in peak annual funding, it took NASA less than one-third of the distance from the $2.2 billion peak funding of the fully-reusables to the $1 billion of the OMB. This move had addressed the easiest part of the problem; the rest of the solution would prove considerably more elusive.

The next step came during June 1971, as the new NASA Administrator, James Fletcher, embraced what his agency had previously rejected: a phased approach to shuttle development. This called for the extensive use of interim systems that would make it possible to build and fly an initial shuttle orbiter, with development of the final systems being delayed for several years. Such an approach would be wasteful, for the interim arrangements would cost money and yet would serve merely as a stopgap. Phased development also carried political risks, for in Washington, few things are so permanent as a temporary solution. If NASA could get any kind of shuttle into space, even one of interim design, it might face strong opposition and long delays before it could win permission to build the Shuttle it truly wanted. A phased approach, however, would spread the program over a term of years, reducing the all-important peak funding level.

Fletcher had formally taken over his office on May 1. On June 16, in his first major decision, he made an announcement:

The preferred configuration which is emerging from these studies is a two-stage delta wing reusable system in which the orbiter has external tanks that can be jettisoned.

Although our studies to date have mostly been based on a concurrent approach in which development and testing of both the orbiter and booster stages would proceed at the same time, we have been studying in parallel, the idea of sequencing the development, test and verification of critical new technology features of the system. We now believe a “phased approach” is feasible and may offer significant advantages.i [Fletcher, statement, June 16, 1971; Aviation Week: June 21, 1971, p. 19; June 28, 1971, p. 16; Gomersall and Wilcox, Working Paper.]

The SSME represented a potentially important element of this approach. It had been slated to receive early attention and funding, for it was to power both Shuttle stages. Its development therefore would pace the entire program. An alternative engine did exist: Rocketdyne’s J-2S was an uprated variant of the J-2 engine used in Apollo. It would lack the performance of the SSME, while delivering considerably less thrust. A cluster of these engines nevertheless would push a shuttle orbiter into space, though with a greatly reduced payload weight. Also, use of the J-2S would permit a delay (potentially a long one) in proceeding with the SSME. Indeed, Max Faget was already incorporating the J-2S in a number of his orbiter designs. [Rocketdyne, Expendable Launch Vehicle Engines; Jenkins, Space Shuttle, pp. 110, 113-115.]

Most of the cuts in peak funding, however, would come by putting off plans to develop a fully-reusable booster, even one of smaller size and simplified design such as one of the new heat-sink versions. NASA instead would fly its orbiter atop an existing rocket stage such as the S-IC, the first stage of the Saturn V. By delaying development of a fully-reusable booster for three years, the agency could cut the peak funding to $1.3 billion per year. This would represent a reduction of nearly a billion dollars from the proposed peak funding levels of the Phase B studies, and would put NASA within hailing distance of the OMB requirement.

While the move to external orbiter tankage represented ingenuity, Fletcher’s decision amounted to desperation. Dale Myers, the Associate Administrator for Manned Space Flight, admitted to Aviation Week that phased development might prove to be impractical. Fletcher himself wrote a letter to a leading shuttle critic, the space scientist James Van Allen: “The political cards are so heavily stacked against this program…that no opposition from the scientific community is necessary. I think you are shooting at a dead horse.” [Letter, Fletcher to Van Allen, July 12, 1971; Aviation Week, June 21, 1971, p. 19.]

Nevertheless, the prospect of an interim booster spurred hope among the contractors that had products ready to offer. Boeing’s situation now was advantageous, for that company’s S-IC was the only immediately-available stage with the power to carry a full-size shuttle orbiter. For Boeing, NASA’s new interest in that stage also represented a reversal of fortune. Only a few months earlier, the firm was looking ahead to an imminent shutdown of its Saturn production facility. Now it could cherish the hope that production of this rocket stage might continue after all.

Fully-reusable shuttle orbiter with the S-IC used as an interim first stage. (Grumman)

Martin Marietta was also in the picture. This firm had actively promoted the Titan III-M, in an era when NASA had been willing to consider a small shuttle orbiter that would amount to an enlarged Dyna-Soar. Though the company had done little of significance for the Shuttle after 1969, now, in mid-1971, it came forward with a new concept, the Titan III-L (“large”). This would use a new liquid-fueled core with a diameter of 16 feet, compared to 10 feet for the standard Titan III, and with up to six solid-fuel boosters of 120-inch diameter.

David LeVine, Martin’s vice-president for launch vehicles, noted that the solid boosters were already in production at United Technology Corp., and could readily be lengthened to yield more thrust. Though the core would be new, it too would use existing engines from Aerojet General. Though the Titan III-L would be expendable, it would cost no more than $30 million per launch, compared to $73 million for the S-IC. The Shuttle orbiter riding atop the new Titan would certainly not resemble Dyna-Soar; it would be a full-size orbiter, carrying up to 65,000 pounds of payload. [Aviation Week: June 28, 1971, p. 16; July 12, 1971, p. 38; August 2, 1971, pp. 40-41; Report MCR-71-309 (Martin Marietta).]

The principal builders of solid rocket motors — Thiokol, Aerojet, United Technology, Lockheed Propulsion Co. — were prepared to make a pitch for their own units as well, arguing that suitable clusters could also provide a good interim shuttle booster. A few years earlier, these firms had built and test-fired rockets with diameters of 156 and even 260 inches. This technology had subsequently been set aside as having no immediate application. Now, however, with the Shuttle needing an interim booster, these big solid motors might see their day.

A fourth approach came from NASA-Marshall: the pressure-fed expendable booster. It amounted to reinventing the liquid-fueled rocket, using approaches selected for their simplicity. Conventional rocket stages used structures of thin-gauge aluminum that saved weight. Their engines relied on turbopumps that pumped the propellants to high pressures, with the engines operating under internal pressures that were similarly high. Such engines offered good performance and strong thrust from compact and lightweight units. The turbopumps, however, were costly and difficult to develop, and at times were prone to failure.

Recoverable pressure-fed booster. (McDonnell Douglas)

Marshall’s new concept did away with the turbopumps, relying on gas pressure within the propellant tanks to push the fuel and oxidizer into the engines. Though these engines would have to be of new design, their lack of turbopumps would greatly ease the problem of development. They would be larger and heavier than their pump-fed counterparts and would give less performance. Moreover, the booster would gain weight, for it would require heavy thick-walled tanks to contain the pressure. Though this approach was inelegant, flying in the face of the quest for high performance that marked the SSME, it offered one more route toward reducing the peak annual funding. [Jenkins, Space Shuttle, pp. 122-123; Aviation Week, June 28, 1971, p. 16.]

This plethora of possibilities reflected the use of external orbiter tankage, which reduced the staging velocity and made it easier for a booster to do its job. This diversity of boosters meant that there now was no clear reason to choose any of them. The wide range of alternatives recalled the era of the late 1960s, when a hundred flowers had bloomed and when neither NASA nor the Air Force had yet developed a convincing idea of how a shuttle should look.

Though the contractors might have helped by settling on a preferred type of booster, this happened only in part. Early in September, North American declared that all of them appeared acceptable, and recommended deferring a choice. Grumman also found little reason to prefer any of them-but noted that within an interim program of 30 flights or fewer, the S-IC, built by its partner Boeing, would offer lower costs because it was already in hand and would not demand up-front spending for development. Lockheed gave the nod to a cluster of 156-inch solid boosters. McDonnell Douglas did the same, but also had nice words for the Titan III-L. [Reports SV 71-40 (North American Rockwell); LMSC-A995931 (Lockheed); B35-43 RP-21 (Grumman); Interim Report (McDonnell Douglas).]

Having thoroughly muddied the waters with these expendable boosters, NASA officials proceeded to do an about-face as they learned that they might indeed build a reusable booster after all. This happened as further studies of external-tank orbiters showed that they could cut the staging velocity to 5000 and even below 4000 ft/sec. This further enhanced the prospects for reducing the booster size and easing the problem of its thermal protection.

Though it lacked wings, the pressure-fed booster became a candidate for reusability because its thick aluminum skin would easily serve as a heat sink. This same robust skin would allow the vehicle to come down by parachute and land in the ocean, surviving the impact and the subsequent perils of the sea. It would enter the water 200 miles offshore; a boat would then bring it back. No one was prepared to describe this as graceful; with this form of makeshift added to those of its design, the concept was unofficially called the Big Dumb Booster. Such dumbness seemed, however, to promise a new path to wisdom.

A more elegant reusable booster concept came from Boeing, which proposed to remodel its S-IC by turning it into a big airplane. It would receive wings, a tail, a nose with a flight deck, and 10 jet engines for the return to its launch site. Though the standard S-IC had never been built for reentry and reuse, thermal protection would not be a problem; modest thickenings of its aluminum skin now would provide heat sink. To emphasize its short-term feasibility, Boeing’s technical artists presented top and side views in lavish detail, even specifying the location of the onboard power units and the choice of tires for the landing gear. At a time when NASA still expected to defer building a flyback booster for several years, one member of the study team emphasized that “our proposal is the reusable booster.”

Winged S-IC stage. (Boeing)

By late September, NASA was ready to abandon phased development, returning to the original plan of simultaneously building the booster and orbiter. The booster would be either the winged S-IC that used standard F-1 engines, or the Big Dumb Booster with pressure-fed propulsion. In turn, the orbiter would use phased technology. It would have a full-size payload bay, but would use four J-2S engines; the SSME program would go on the shelf. For thermal protection, the orbiter would rely on an ablative heat shield, even though this would demand costly replacement after every flight. In time, however, the SSME could be resurrected for use in an upgraded orbiter. This orbiter would also use tiles or hot structures, as reusable and low-cost thermal protection.

The development costs and peak annual funding for the complete Shuttle, in billions of dollars, now looked highly encouraging [Aviation Week: September 20, 1971, pp. 16-17; October 11, 1971, p. 23; October 25, 1971, pp. 12-13; Reports LMSC-A995931 (Lockheed); MDC E-0497 (McDonnell Douglas); B35-43 RP-30 (Grumman); SV 71-50 (North American Rockwell); Ballistic Recoverable (Boeing)]:

These costs compared with estimates prepared by the Aerospace Corp. for a two-stage fully-reusable shuttle: development, $9.92 billion, with a peak of $2.34 billion [Morgenstern and Heiss, Analysis, May 31, 1971, p. 0-15]. The pressure-fed booster yielded a development cost less than half that value, with a peak comfortably under the OMB ceiling of $1 billion. The winged S-IC was only slightly more costly, and it preserved all the operational advantages of the fully-reusable boosters of Phase B, on which NASA had placed so much hope.

The new booster concepts did even more, for they addressed major technical deficiencies of the Phase B boosters. Thermal protection had appeared particularly difficult, at a time when tiles were too new to trust. Charles Donlan, the Shuttle program director, put it this way:

Phase B was the first really extensive effort to put together studies related to the completely reusable vehicle. As we went along, it became increasingly evident that there were some problems. You had to develop two hypersonic aircraft configurations, simultaneously. The engine problem was compromised. Trying to use common engines made them not optimized for either case. We ran into a problem of pilot escape from the booster in the event of an abort. We never could quite figure out what to do about it. And then as we looked at the development problems, they became pretty expensive.

We learned also that the metallic heat shield, of which the wings were to be made, was by no means ready for use. The slightest scratch and you are in trouble. It became increasingly evident that you want to have the cheapest possible configuration, but you put all this time and effort on a vehicle, the biggest part of which (the first stage), its only role was to get the orbiter up high enough for it to fly itself. So here you’re spending all this effort on a part of the system that had no basic payoff. The important thing is the orbiter-that is the payoff.

So you see, it was easy to say, “Why do we break our necks putting twelve engines in this damn big reusable booster? You cannot get the pilots away, the metallic heat shield is going to give you all kinds of problems, to do it with ablative stuff makes it too heavy; drop it entirely. That started the ball rolling into other types of boosters for the orbiter.

The merits of an aluminum heat-sink booster appeared stronger yet when one recalls that the most plausible Phase B alternative, which used hot structures in the fashion of the North American Rockwell design, amounted to covering much of the surface of a craft the size of a Boeing 747 with alloys that had previously seen use only in turbine blades. By comparison, the simplicity of aluminum heat sink was overwhelming. It was as much as to say that instead of attempting to leap with one swoop into the metallurgy and launch vehicle design of the twenty-first century, engineers instead could build the booster using design methods that dated to World War II.

The Phase B work had also pointed to demanding issues of safety. To reduce weight to a minimum, the internal tanks had to carry part of the Shuttle’s weights and loads. The resulting stresses would tend to produce leaks. Hydrogen leaks are difficult to detect, raising the prospect that hydrogen could build up beneath the skin of an orbiter, to produce a damaging fire or explosion. External tankage solved this problem, at least for the orbiter. A leak of propellant now might indeed be detected, since it would occur in plain view. The leak would also be far less dangerous, for the propellant would waft away on the winds rather than build up to form a dangerous concentration.

The Phase B shuttles also promised severe difficulty in technical development. Airplanes and spacecraft, as a rule, tend to gain weight in the course of development. A two-stage shuttle could accommodate such weight growth by enlarging the tanks, to allow them to carry more propellant. With the tankage being internal in both stages, this would demand extensive redesign of one or both stages — which would introduce opportunities for further weight growth. External tankage addressed this problem as well. A simple lengthening of the tanks would do, leaving both booster and orbiter untouched. [John Mauer interview, Charles Donlan Washington, October 19, 1983, pp. 19-20; Loftus et al., Evolution, pp. 15-18.]

It thus appeared that in mere months, NASA had scored an impressive coup, addressing these technical issues while simultaneously meeting the OMB’s cost limits. As with the Mathematica study, however, OMB officials again found reason aplenty to view this work with skepticism.

The new configurations closely suited NASA’s institutional arrangements, which dated to the time of Apollo. Those arrangements had given NASA-Marshall responsibility for the Saturn launch vehicles and their engines, with the Manned Spacecraft Center holding responsibility for the Apollo moonship, with its piloted spacecraft and lunar lander. This division of authority had carried over to the Shuttle, with Marshall in charge of the booster and MSC dealing with the orbiter. The Shuttle certainly needed an orbiter; hence MSC’s prospects were clear. It was less obvious, however, that the Shuttle needed a booster, particularly if it was to be complex and costly. At Mathematica, Klaus Heiss had managed the Shuttle studies and now was recommending simplified designs within NASA. He met resistance, and as he told the National Journal, “For a long time some people over there kept seriously telling us, ‘We can’t go that route, because we’ve got to have something for the Marshall Space Center as well as something for the Houston Space Center.’” [National Journal, August 12, 1972, p. 1299.]

NASA-Marshall had taken shape as the lengthened shadow of Wernher von Braun, its founder and longtime director. He and his fellow veterans of the wartime V-2 effort, who still held senior positions, had long since nailed their flag to the mast of liquid-fuel rocketry, and had left the development of large solid rockets to the Air Force. The recent Shuttle studies reflected this strong Marshall preference. Thus, early in September, the prospect had emerged that the Shuttle might use a cluster of 156-inch solids as its booster. Lockheed and McDonnell Douglas had both made outright selections of this choice, while North American and Grumman had found no reason to reject it.

NASA thus had a clear opportunity to seek a phased-development program with these solids as the interim booster. Instead, in a directive dated September 12, NASA had instructed its contractors to set aside their studies of phased development and to return to assessments of concurrent development, using two new reusable booster concepts: the pressure-fed and the winged S-IC. Both had NASA-Marshall written all over them. Of course, Marshall was the world’s leading center for rocket development; its voice would certainly be heard. NASA’s decision, however, had amounted to a peremptory dismissal of solids. The results of the new studies were a little too good to be true. [NASA Tech. Directive GAC-3, 16 September 1971; Reports B35-43 RP-28 (Grumman), p. 11; SV 71-50 (North American Rockwell), pp. 2, 3, 5.]

The winged S-IC, for one, promised the fully-reusable booster of NASA’s hopes. Its shuttle would do nearly everything that the Phase B fully reusables were to accomplish, with a billion dollars less in peak annual funding. Yet because this booster was to grow out of the standard S-IC and would use the F-1 engine, it would continue to demand work aplenty from both Marshall and its contractors. The budget analysts at OMB had been trained to spot flim-flam. They had reason for doubt when they saw that in an astonishingly brief time, NASA had succeeded in devising a new shuttle design with a flyback booster that would make the agency’s wishes come true — while still purporting to meet the cost goals of the OMB.

Projected cost savings also raised questions, for they seemed disproportionately large when contrasted with the relatively modest engineering changes that had led to the shuttle with the winged S-IC. Were the Phase B cost estimates valid? They were certainly high, and if NASA could receive largesse on such a scale, it could continue to maintain itself in the style to which it had become accustomed. On the other hand, one could equally question the low estimates of the recent exercises. Lockheed’s invited particular scrutiny, for it was the lowest-and its peak level, interestingly, was just a hair under the OMB mark of $1 billion. Everyone knew that Lockheed had won the C-5A contract with an unrealistically low bid; everyone also knew that the man who had presided over that bid, Dan Haughton, was now the firm’s chairman. Was Lockheed attempting again to buy in? Were the other contractors very far behind?

Even if one cared to accept everyone’s cost estimates as reflecting good faith, the trend of these estimates invited further questions. On its face, this trend meant that in only six months, NASA had cut the planned cost of development in half, from $10 billion to $5 billion, while sacrificing little in the Shuttle’s capability. These cuts had been won at a price, for the cost per flight was now on the rise-while still remaining low enough, at least in the published estimates, to make the Shuttle attractive to users. Still, it was appropriate to ask if NASA had any other rabbits it might pull from a hat. Thus, late in November two OMB staff members, Daniel Taft and the economist John Sullivan, sent a memo to Donald Rice, an OMB assistant director:

In the light of the innovative Shuttle designs which have been forthcoming over the past several months, we believe that the best procedure would be to provide NASA with a constraint in terms of total investment cost (say, $3-4 B) rather than have us try to define a preferred configuration. If NASA’s resourcefulness to date in changing the Shuttle’s design is any guide, we have not yet begun to see what they could achieve if they really tried to optimize a system for $3-4 B. [Memo, Taft and Sullivan to Rice, November 29, 1971.]

Rice’s domain included the Economics, Science, and Technology Programs Division, which covered NASA. He reported directly to the OMB deputy director, Caspar Weinberger. He, too, had noted that NASA’s recent exercises in redesign had brought the Shuttle very close to what NASA had wanted originally. Four years later, he noted particularly that NASA’s basic assumptions had seemed to be set in concrete:

I guess what sticks in my mind more than anything else about it was the difficulty of getting any solid attention paid to alternative designs. I don’t mean alternative in the technical detail sense, but alternative in terms of mission requirements and why that mattered. How hard it was to get an examination of alternative specifications of what you would like to accomplish, and the systems designs that reasonably derived from that will lead to each different specification of what you wanted to do.

Rice added that within the Pentagon, “they do a hell of a lot better job of looking through the alternatives before they head down one of those roads.” [John Logsdon interview, Donald Rice, November 13, 1975, p. 1.]

Even so, there had been change within the Shuttle program, at least in terms of its engineering design. The two-stage fully reusables were dead, and Charles Donlan would not miss them, later declaring, “It wasn’t till the phase B’s came along and we had a hard look at the reality of what we meant by fully reusable that we shook our heads saying, ‘No way you’re going to build this thing in this century.’ As I say, ‘Thank God for all the pressures that were brought to bear to not go that route.’” [John Mauer interview, Charles Donlan, Washington, October 19, 1983, pp. 23-24.]

The winged S-IC soon would die as well, for it appeared more costly than the pressure-fed reusable booster which, though it might look and fly like an ugly duckling, was a graceful swan in the realm of budgets, and would survive into the next round of designs. This round would resurrect the solid-propellant booster, and would determine the shape of the Shuttle in the form that would actually be built.