Technology Bypasses the Space Station
 During the 1950s, as Walt Disney and Collier's presented the space station concept to the American public, the rapid pace of technical development was making it obsolete before it could ever be built. The concept had taken form in an era when radio was the only well-developed electronic technology. It was easy, therefore, to imagine that space flight would demand large orbiting crews to conduct satellite communications, weather observation, and military reconnaissance. Like a base in Antarctica, the space station would support these crews with comfortable accommodations inside a centralized facility.
This point of view appeared not only in the writings of Wernher von Braun, but in the work of his fellow visionary Arthur C. Clarke. In 1945, Clarke proposed building communications satellites in geosynchronous orbit, at an altitude of 22,300 miles. They would circle the earth every 24 hours, to remain fixed in position in the sky:
Even then, in 1945, rocket researchers were broadening the use of radio by introducing telemetry: the automated transmission of instrument readings. Telemetry developed in the technology of weather balloons, which could carry meteorological instruments to high altitudes. By transmitting the instrument readings, telemetry eliminated the need to physically recover the instruments following a long flight. In addition to this, weather balloons (and rockets) required equipment of minimal weight. During World War II, telemetry was used actively diuring test flights of the V-2. After that war, when Von Braun brought his V-2s to the U.S. and carried out a program of instrumented flights in New Mexico, telemetry again played an important role. 2
In space flight, telemetry made it possible to envision automated spacecraft. As part of the Collier's series, Von Braun offered a proposal for such a craft in 1953. It was to carry rhesus monkeys, along with a TV camera for observation of clouds and weather patterns. Collier's called it a "baby space station," describing it as the "first step in the conquest of space." Chesley Bonestell, in his lyric style, portrayed it in a closeup view, soaring high over New York City.
This spacecraft, however, would serve as a prelude to the full-size space station; in no way would it represent a substitute. In Von Braun's words, "We scientists can have the baby rocket within five to seven years if we begin work now. Five years later, we could have the manned space station."3
Two other technical developments allowed automated satellites to come into their own. The first was the development of electronic circuits that had long life. Largely from the work at Bell Telephone Laboratories, it was here that the first transistors took form. Bell Labs also introduced the solar cell, a thin wafer of silicon that could transform sunlight directly into electric current. In addition....
....to this, while Arthur Clarke wrote of communications satellites, it was another of Bell Labs' specialists, John Pierce, who developed the invention that allowed these spacecraft to emerge as working technology. This was the traveling-wave tube, an electronic amplifier that could work with a broad range of frequencies. 4
In his 1945 paper, Clarke was more able to envision frequent space supply flights in high orbits than to foresee electronic circuitry that would operate routinely and reliably for years, without maintenance. Crews in their orbiting stations would spend a great deal of time replacing vacuum tubes. The situation was not much different in 1953, when Von Braun proposed his "baby space station." He envisioned a time in orbit of only 60 days, which was about as much as he could expect given the limits of circuitry at that time. As early  as 1958, however, the Vanguard 1 satellite demonstrated the prospect of long life. It lacked instruments and carried only a radio transmitter, powered by solar cells and was able to transmit for over six years.5
Another important development brought the advent of spacecraft that could operate autonomously and return from orbit. This project, known as the Corona project, was run by the Central Intelligence Agency, with Lockheed as the contractor. Their spacecraft, called the Discoverer, was able to stabilize while in orbit and point a lens at the earth below. They also operated an automated camera, winding the exposed film into a protected cassette. At an appropriate moment, the spacecraft then released a reentry capsule that fired a retro-rocket. The capsule deployed a parachute to land within a specified target area. Air Force cargo planes were then often able to snatch the capsule in mid-air. 6
It took over a dozen satellite launches before the CIA got this complex system to work successfully. While the first launch, Discoverer 1, flew in February 1959, it was not until Discoverer 13 and 14, in August 1960 that the program achieved success.7 Its significance then was undeniable. The analyst Jeffrey Richelson described space reconnaissance as "one of the most significant military technological developments of this century and perhaps in all history. Indeed, its impact on postwar international affairs is probably second only to that of the atomic bomb. The photo-reconnaissance satellite, by dampening fears of what weapons the other superpower had available and whether military action was imminent, has played an enormous role in stabilizing the superpower relationship." 8
These developments-telemetry, long-life electronics, onboard autonomy-completely changed the prospects for space flight. No longer would it be necessary to build Von Braun's 7000-ton cargo rockets or to support large crews in orbiting stations. Instead, the nation would proceed by developing launch vehicles from the ICBMs and similar missiles that the Air Force was building for military purposes. Satellites would take shape as instrumented craft of modest size and weight. In turn, the space station ceased to hold the attention of visionaries such as Von Braun, who went on to influence policy.
Rather than emerging as a matter of urgency for the near future, the space station became something that might be built in the distant future.
In May 1961, President Kennedy committed NASA and the nation to a major effort in piloted space flight that had nothing to do with a space station. The goal, instead, was to land astronauts on the moon. In doing this, NASA completely bypassed the classic approach of first building a space station and then using it as a base or staging area for the lunar mission. Instead, as a single Saturn V rocket carried a complete moonship with a crew of three, NASA went for the moon in one fell swoop,.
The concept of an orbiting station, however, did not go away. If it now offered no obvious path for use in space applications, the space station still  promised considerable value as a science center, supporting astronomy and studies of the earth. Kennedy's effort aimed at a moon landing; it was easy to imagine a permanent base on the moon. A space station, in earth orbit, could demonstrate and test many critical technologies. As an essential prelude to an eventual mission to Mars, it also could test the ability of astronauts to remain healthy when living for long periods in zero gravity.
The architecture of such stations also changed. The concept of a big rotating wheel fell by the wayside, in favor of designs that could fit atop a rocket as a single payload. The Saturn V could carry close to 300,000 pounds to orbit 9, a capacity that spurred far-reaching thoughts. After 1965, attempts by NASA officials to use this capacity led to the development of a space station called Skylab.
Apollo Applications: Prelude to a Space Station
The ubiquitous Von Braun played a key role in initiating this new effort not because he succeeded in convincing senior NASA officials of the merits of a space station, but rather because he knew that his staff would soon need new work. During the 1960s, he was director of NASA's Marshall Space Flight Center, where large launch vehicles were a specialty. As he stated in 1962, "we can still carry an idea for a space vehicle… from the concept through the entire development cycle of design, development, fabrication, and testing." His domain included the Michoud Assembly Facility near New Orleans, where complete Saturn V first stages were assembled. It also included the nearby Mississippi Test Facility, where these five-engine stages could operate as complete units on a test stand. 10
The development of the Saturn V set the pace for the entire Apollo program. This moon rocket, however, would have to reach an advanced state of reliability before it could be used to carry astronauts. The Marshall Center also was responsible for development of the smaller Saturn I-B that could put a piloted Apollo spacecraft through its paces in earth orbit. Because both rockets would have to largely complete their development before Apollo could hit its stride, Von Braun knew that his center would pass its peak of activity and....
....would shrink in size at a relatively early date. He would face large layoffs even while other NASA centers would still be actively preparing for the first mission to the Moon. 11
At NASA Headquarters in Washington, DC, George Mueller (pronounced "Miller"), associate administrator for Manned Space Flight, understood Von Braun's situation for he had helped to create it. Mueller had been vice president of the firm of Space Technology Laboratories in Los Angeles, a division of TRW and a prime source of technical support for the Air Force's principal missile programs. Mueller had been deeply involved in the Minuteman ICBM effort, and had pushed successfully for "all-up testing," during which that missile fired all three stages and flew to its full range on its first flight.
 Coming to NASA in 1963, he quickly became convinced that he could do the same with the Saturn V. Von Braun had used a cautious step-by-step approach in developing the earlier Saturn I, flight-testing only the first stage before committing to flights of the complete two-stage launch vehicle. Mueller decided that similar caution in flight testing of Saturn V's three stages would push the first lunar landing into the next decade. He won Von Braun's consent to allow Saturn V to fly "all-up" on its first flight by firing all three of its stages. 12
This quickened the pace of development on the Apollo, making it likely that the Saturn V would become available at a relatively early date. It also hastened the day when Von Braun's center would largely complete its work and face layoffs. Mueller's decision, however, also made it likely that surplus Saturn-class rockets would become available and used for purposes other than direct support of moon landings.
In August 1965, Mueller set up a new Saturn-Apollo Applications Program Office. The Saturn I-B emerged as an early focus for attention. This powerful rocket conducted only a limited program of developmental flights for Apollo before giving way to the much larger Saturn V. The Saturn I-B's second stage, the S-IVB, had a liquid-hydrogen propellant tank with a volume of nearly 10,000 cubic feet. There was interest in turning the S-IVB into an orbiting workshop. Mueller later stated that this would match the volume of "a small ranch house. The kind I can afford to buy."
By early 1967, the program called for an initial mission featuring two launches. The first would carry an Apollo spacecraft with its crew of three; the second would launch the workshop, mounted to an airlock and docking adapter. The S-IVB, modified for use in orbit, was to sprout large solar panels along with two floors within the 21-foot wide hydrogen tank. These floors would provide living quarters and work areas. The flight crew would rendezvous with the workshop and dock with the adapter. Inside the spent fuel tank, these astronauts would find an empty, bare-walled space that would require four days of fitting-out to turn into habitable living quarters. The crew would then stay in space for 28 days conducting biomedical tests as their principal activity. A subsequent mission to the workshop would bring a fresh crew to live in space for 56 days. 13
 In addition to Mueller's powerful Office of Manned Space Flight, a separate NASA program center, the Office of Space Science and Applications (OSSA), made its own contribution to the new post-Apollo effort. Within the field of space science, OSSA supported solar astronomy, using spacecraft to observe the sun's at ultraviolet and x-ray wavelengths that do not penetrate the atmosphere. In 1962 and 1965, two Orbiting Solar Observatory spacecraft returned a great deal of useful data and sparked interest in an advanced automated solar observatory. Such plans fit the cyclic activity of the sun itself, which, every 11 years, rises to a peak in the number of sunspots, radiation levels, and magnetic activity. The next such peak was to occur in 1969, leaving ample time for development of the new spacecraft.
OSSA's plans fit the solar cycle much better than the budget cycle. OSSA had little clout, and the demands of Apollo were all-consuming; pressed by its budgetary needs, scientific satellites tended to fall by the wayside. The head of OSSA, Homer Newell, was undismayed. Though his advanced automated observatory failed to win support and had to be canceled, Newell saw that he could seek an even more ambitious solar observatory by hitching his wagon to the star of piloted space flight. Working with Mueller, Newell developped a concept for an Apollo Telescope Mount (ATM), as a second important component of Apollo Applications.
This ATM took shape as a substantial spacecraft in its own right. Requiring its own Saturn I-B to carry it aloft, it also called for its own set of solar panels that would unfold to form a large cross. The program plan called for it to rendezvous with the orbiting workshop early in the 56-day second mission. The astronauts would move it into position and install it as part of the complete space laboratory. With a dozen instruments, the ATM would test the ability of astronauts to conduct useful scientific research by operating sophisticated equipment in orbit. 14
These missions were to herald a major program. Released in March 1966, NASA's initial schedule envisioned 26 launches of the Saturn I-B and 19 of the Saturn V. Flight hardware would include three S-IVB stages intended for on-orbit habitation, four ATMs, and three more capable space stations that would ride atop the Saturn V. The Bureau of the Budget (BoB), an arm of the White House, was not encouraging. Bureau officials were concerned that....
....Apollo Applications might wastefully duplicate an Air Force program, the Manned Orbiting Laboratory. In addition to this, with Apollo reaching the peak of its funding, those officials were in no mood to allow NASA to launch another costly program.
Initial discussions focused on the budget request for FY 1967 that President Johnson would present to Congress early in 1966. Mueller hoped at first for $450 million, with over $1 billion in FY 1968. Bureau of the Budget officials preferred to start by offering $100 million, though they were willing to listen to arguments for $250 million. This part of NASA's budget included Apollo. To keep it on schedule, Mueller had to put Apollo Applications under a particularly severe squeeze with only $42 million (less than a tenth of his initial budget mark) for FY 1967. 15
The FY 1968 budget brought more of the same. Initial discussions between NASA and the BoB chopped the request from $626 million to $454  million, a sum that would get the program off to a good start at least. In his budget message to Congress, Johnson endorsed this figure with an argument that would be heard again in subsequent years: "We have no alternative unless we wish to abandon the manned space capability we have created." Though Johnson and the BOB were now on board, Congress, which cut the authorization to $347 million, was not. Not even the appropriation-more bad news at $300 million-was safe, as the NASA Administrator, James Webb, transferred part of it to other activities. Apollo Applications was left with only $253 million, the lowest level Mueller could accept. 16
It nevertheless was enough, barely, to get the program under way and turn it into something more than a design exercise. As serious engineering activity got under way, however, designers came to realize that they were pursuing an approach marked with pitfalls. The approach continued to call for a "wet workshop," a propulsive stage that would then serve as living and working quarters while in orbit. After reaching orbit, however, astronauts would have to convert the empty fuel tank into these quarters and install a good deal of equipment. As studies proceeded, it became increasingly doubtful that all this could be done.
The alternative would be to build the space station as a "dry workshop"with no provision for use as a rocket stage. Unable to propel itself into orbit, the dry workshop would need the heavy lifting power of a Saturn V. That rocket's payload capacity would make it possible to incorporate the ATM from the outset, rather than having to bring it up on a separate flight. The complete, well-integrated space station could undergo tests and verification on the ground.
While studies of a dry workshop were being conducted at the same time as those of the wet version, they were never endorsed by NASA Administrator James Webb. The sticking point was the need for a Saturn V. The historians Charles Benson and David Compton note that "it had taken all of Webb's power of persuasion to convince Congress and the BoB that Apollo required at least 15 Saturn V launch vehicles, and he would tolerate no suggestion that any could be used for something else."17 When Webb resigned from NASA in October 1968, he took his objections with him. In addition to this, in  December 1968, Apollo 8 carried three astronauts on a successful flight that orbited the moon and returned safely. This was only the third flight of a Saturn V, making it highly plausible that it would indeed be possible to spare one of those behemoths for Apollo Applications. 18
With the mounting technical problems of the wet workshop approach, Mueller became convinced that it simply was not practical. Hence, only a dry workshop could save the program. The new NASA Administrator Thomas Paine became convinced in 1969 that it was necessary to make the switch. His decision was subject only to the success of Apollo 11, the planned first lunar-landing mission. He signed the project-change document on July 18, while Apollo 11 was en route to the moon. Four days later, with the landing accomplished and the astronauts homeward bound, the Apollo Applications program manager, William Schneider, sent telexes to the NASA centers that directed them to proceed with the dry workshop.
Program cutbacks, however, had taken their toll. Apollo Applications, initially conceived as a long-running extension of Apollo, was down to a single workshop supported by three astronaut crews flying the Saturn I-B. There was hope for a second workshop that would carry different equipment. The committee considered close to a hundred possibilities for a new name for the program, including "Socrates" and "LSD." The winning name, "Skylab," came from Lieutenant Colonel Donald Steelman, an Air Force officer on duty with NASA. The new name, which replaced Apollo Applications, was formally adopted in February 1970. 19
Space Station Concepts of the 1960s
There was only a single Skylab orbiting workshop in existence. Though NASA had built a second model, because there were no funds to launch this spacecraft, it wound up on display at the National Air and Space Museum.20 To this day, Skylab remains the closest thing to a true space station that NASA has ever built and launched. Nevertheless, it represented no more than a half-step toward that goal.
 Skylab grew out of Apollo Applications, which merely sought to make good use of Apollo launch vehicles and equipment. Though the Skylab spacecraft strongly modified the standard S-IVB rocket stage, its design was heavily constrained. The 22-foot diameter of Skylab followed from the diameter of the S-IVB, even though the Saturn V could accommodate payloads of up to 33 feet across. Similarly, although Skylab included the ATM as part of its package, its total weight, 165,000 pounds, fell well short of the lifting power of the Saturn V. These restrictions arose because the dry workshop, which used the Saturn V, developed out of the wet workshop, which was to have used the much smaller Saturn I-B. 21
In addition, Skylab was not permanently inhabited. It supported three crews in orbit, during 1973 and 1974, who stayed respectively for 28, 59 and 84 days. Though the last such mission continues to hold the record for duration in U.S.-built spacecraft, Soviet and Russian cosmonauts have stayed in orbit for up to 437 days in the Mir station. Following the return of the third Skylab crew, in February 1974, NASA made no further attempt to use this valuable facility. Skylab's orbit, left to decay, burned up in the atmosphere in July 1979. 22
Amid its limitations and its shrinking budgets, Apollo Applications, however, was important. Not just a paper study, it was a true and funded program, with a project office at NASA Headquarters that stood alongside similar offices for Gemini and Apollo.23 It thus gave considerable hope to those in both NASA and the industry who were carrying out studies for the next space station. During the 1960s, a number of studies sought to define such a station.
NASA's Langley Research Center took an early interest in such studies, setting up a space station office within its Applied Mechanics and Physics Division. Early work, from 1959 to 1962, focused anew on the rotating-wheel configuration. At the outset, the Langley designers considered a range of shapes that could rotate to provide artificial gravity. Like Potocnik and Von Braun before them, they decided the wheel was best. With a radius of 75 feet, it would rotate at four revolutions per minute, producing two-fifths of normal gravity.
Langley then contracted with North American Aviation (NAA) to carry out further studies. A prime question was how to fit so large a structure into....
....the cargo volume of a Saturn V. NAA changed the wheel to a hexagon composed of six long cylinders joined at their ends. These would fold into a package 103 feet long by 33 feet in diameter. Once in orbit, mechanical screw jacks would unfold the hinged parts. The complete space station would include a hub with a docking facility for Apollo spacecraft. With telescoping spokes joining the hub to the hexagon, the station's volume of 45,000 cubic feet would accommodate up to 36 crew members. 24
In size between Potocnik's concept of 1928 and Von Braun's of 1952, NASA's concept represented a brilliant attempt to bring the rotating wheel into an era in which major tasks, including piloted flight to the moon, would be carried out in space. Even so, it was behind the times. The project's emphasis on artificial gravity was better suited to an earlier age when large crews were expected to live in comfort. At the same time, by 1960, tasks that were to be conducted by astronauts were ready for automated electronics. In addition to this, by 1963 it was clear that studies would represent an important rationale for a space station. Subsequent concepts reflected these changes.
Langley's next round of studies, called the Manned Orbiting Research Laboratory (MORL), rejected the rotating wheel once and for all. Late in 1963, Douglas Aircraft won this study contract and went on to build the Skylab workshop. In many ways, MORL illustrated what Apollo Applications might have accomplished if it had been given high priority and ample funding.
Rather than seeking to support large crews in the comfort of artificial gravity, MORL emphasized small crews that would live in weightlessness in versatile, compact stations. The basic station was to fly atop a Saturn I-B and hence had that rocket's diameter of 22 feet. Weighing 30,000 pounds at launch, MORL would enclose 9000 cubic feet of internal volume, with a crew of six. Each astronaut would serve a six-month tour of duty. A modified Apollo spacecraft, riding its own Saturn I-B, would carry supplies along with new three crew members to the space station.
Specialized equipment would enhance the usefulness of MORL. It would carry astronomical telescopes. A crew-tended radar would support large-scale topographical mapping. Douglas Aircraft also proposed to install a nine-lens camera system for observation of the earth's surface and weather at a variety of wavelengths. With astronauts tending a lab full of plants, animals and  bacteria, additional modules would research new fields such as life sciences. The addition of other such modules would allow the basic station to expand to house nine astronauts rather than the original six. Selected crew members would remain in orbit for as long as a year.
Use of the Saturn V would enable the MORL to fly in orbits as high as 23,000 miles while continuing to receive resupply. The MORL would be able to fly to lunar orbit to map the moon's surface. It would be able to land on the moon and to serve as a base. Serving as a test bed for systems intended for use in a piloted mission to Mars, MORL also might evolve into an important element of a spacecraft built to carry out such a mission.
At the Manned Spacecraft Center in Houston, other investigators agreed that a space station could represent an intermediate step toward a mission to Mars. That center had its own space station group that had contracted with the Space Division of the Boeing Co. to conduct the pertinent study. Completed in 1967, that study envisioned a Mars spaceship that also could serve as an earth-orbiting station.
The Mars ship would take the form of a two-deck module, 22 feet in diameter, with room for both crew members and equipment. For use as a space station, the vehicle would add a second module, together with a central section, midway along the station, that could accommodate the docking of two Apollo spacecraft. With a weight of 248,000 pounds, this complete station would ride a Saturn V to orbit. It would support a crew of eight, with these astronauts flying on the Saturn I-B, in Apollo craft modified to carry four rather than the usual three people. Two such launches would provide the initial staff. Subsequent flights every 90 days would bring fresh crew members as well as new supplies. The station would remain continuously occupied for two years.
Without resupply or revisit en route, the Mars mission would also last two years. Mission designers would chop the space station in two, retrieving the basic two-deck module and staffing it with a crew of four. After being placed in orbit by a single Saturn V launch, additional Saturn V flights would carry fully-fueled S-IVB stages to boost the Mars ship toward its destination. While it would fly past and not land on that planet or even orbit it, the mission would drop off planet probes, landers, and an orbiter during this flyby. During the....
....close approach to that planet, the flight to Mars would culminate in an 11-day period of intense crew activity followed by the long voyage home. 26
Not everyone agreed that a space station should serve as a way station for flight to Mars. An alternate viewpoint stressed the usefulness of such stations for science alone. This view found support at NASA's Marshall Space Flight Center. A 1966 study there noted that a proper science station could not be all things to all people. It was argued that different sciences would impose characteristic demands that would be mutually incompatible.
Astronomy in space, for example, would require gamma-ray, x-ray, optical, and radio telescopes. These would have to point in fixed directions during their observations, maintaining stability to within 0.001 degrees. A due-east launch from Cape Canaveral could put them in orbit, with an inclination to the equator of 28 degrees. By contrast, observation of the earth's surface and weather would ideally require a polar orbit that demands more energy at launch. An earth-observing station would have to turn slowly to point continually downward, rather than stand at a fixed position in space. It could work  with a stability of 0.05 degrees. Biomedical experiments, including long-duration studies of the human response to weightlessness, would be even less demanding. Able to work in any orbit, they would dispense with the costly control systems necessary for pointing and stabilization.
The Marshall study thus called for two stations, each with a crew of nine and a lifetime of five years for the station. They would fly to orbit atop the S-IVB stage of a Saturn V. One station, supporting astronomy, would fly due east from the Cape. The second station, supporting meteorology and earth observations, would not use the hard-to-reach polar orbit, but would achieve an intermediate inclination of 55 degrees. This inclination would still permit coverage of the world's major land masses. Biologists and life-science specialists, not requiring a specific orbit, could build a specialized module that could fly as part of either station. 27
It is important to note that these studies lacked the support of a NASA Headquarters program office similar to that of Apollo Applications after 1965. These studies, however, did have the attention of center directors. In 1963, the original MORL Studies Office reported directly to Floyd Thompson, the director of NASA-Langley.28 Similarly, it was no secret that Wernher von Braun, director of NASA-Marshall, had a strong and ongoing interest in space stations. With no one at Headquarters who was ready to take those studies and push for their fulfillment, the space station represented only a possible new direction for NASA. In no way was there a commitment to pursue that direction.
In addition, these studies reflected the characteristic point of view that space stations could offer intrinsic advantages. In 1968, Robert Gilruth, director of the Manned Spacecraft Center, defined such a station as "a site in space developed to support men, experimental equipment, and operations permanently and to take advantage of the favorable economies of size, centralization, and permanency-in terms of power, volume, instruments, communications, data reduction, and logistics." 29 This amounted to an assertion that those "favorable economies" actually existed, a point from which both Congress and the Budget Bureau soon would differ.
Likewise, it was not easy to assume that space stations would win support on their merits for use in science. The concepts of the day anticipated the routine  use of the Saturn I-B with the Apollo spacecraft for resupply and crew rotation. The Apollo 7 mission, which had flown atop the Saturn I-B in 1968, cost $145 million. Two years later, a single flight of a Saturn V with its moonship would cost up to $375 million. By contrast, in FY 1970, the National Science Foundation, which sponsors a broad range of basic research in a large number of fields, received a budget of $440 million.30 Indeed, it would take a true believer to assert that a Saturn V, even with an Apollo mission, could offer the scientific return of a year's worth of grants from the NSF to the nation's universities and research centers.
This point was not lost on the advanced-planning designers who were nurturing their space stations. They saw that the expensive Saturn V might not remain the only way to launch a large station; a reusable launch vehicle might cut costs while offering even greater lifting power. In addition to this, it might prove feasible to dispense with the Saturn I-B, replacing it with a low-cost launcher of intermediate size. A number of specialists pursued these hopes during the 1960s, as they allowed their imaginations to run free. In pursuing their designs, they laid a considerable amount of groundwork for the serious studies of a space shuttle that followed.
Early Studies of Low-Cost Space Flight
No one could deny that space flight was expensive. Launch vehicles flew only once. There was no way to reuse them; they launched their payloads and then splashed into the ocean. A Saturn I-B cost $45 million, excluding its Apollo spacecraft and flight operations; a Saturn V cost $185 million. For these rockets to carry three astronauts costs as much as $60 million per person. 31
Advocates of reusable launch vehicles would say that using throwaway Saturns was tantamount to flying a planeload of passengers across the Atlantic and having that airliner fly only once. It is a measure of the truly enormous cost of space flight that this comparison was off by three orders of magnitude. The Boeing 727, a popular jet of the 1960s, had a sticker price of $4.2 million. It carried 131 passengers. Had each such plane made only a single flight, the cost of a ticket would have been some $30,000.32 The corresponding price for  a ticket on a Saturn V was 2,000 times greater. A more appropriate if less exact simile came from Newsweek in 1961.33 It compared the space race to the potlatch ceremony of the Kwakiutl tribe of the Pacific Northwest, whose members vie to throw the most valuable objects into a fire. Clearly, the nation was unlikely to persist in this celestial potlatch unless it had the most compelling of reasons.
An initial step toward reusability came at NASA-Marshall during 1961 and 1962, where engineers sought to learn whether a high-performance rocket engine could survive a dunking in seawater. They worked with the H-1, a standard engine from Rocketdyne that went on to power the Saturn I-B. Following immersion, investigators dismantled the engine, checked its parts for corrosion, reassembled it, and ran it successfully on a test stand. Thus, it was proven that this powerful engine, rated at 187,000 pounds of thrust, could withstand a bath in seawater and return to service. 34
The next question was whether a Saturn-class first stage could be recovered for reuse. There was considerable interest in using a flexible and deployable wing invented by Francis Rogallo of NASA-Langley. The "Rogallo wing" later found its niche as a type of hang glider, allowing enthusiasts to fly from clifftops and soar on uprising air like birds. It also was used as a directional parachute, permitting a large booster to descend by gliding to a designated recovery point.
Studies showed that this approach would not work with existing first stages such as the Saturn I-B. Because they had not been designed for recovery, they lacked the storage room for the furled Rogallo wing. 35 Thus, it would not be possible to introduce reuse by the simple approach of mounting a deployable wing to a Saturn booster. Studies funded by NASA-Marshall, under the name "50- to 100-Ton Payload Reusable Orbital Carrier," showed, however, that NASA might achieve better results by installing fixed wings on the Saturn V's first stage.
The new first stage would use that booster's standard engines, adding landing gear, a pilot compartment, insulation to protect against the heat of atmosphere reentry, and large wings, sharply swept, with big vertical fins at the tips. These modifications would add 300,000 pounds of weight. The  second stage, however, would retain its full lifting power. Thus, the payload would be decreased by only 20 percent.
Smaller winged rockets also drew interest, as analyses showed that even with parachutes, recovery of any craft at sea would be both costly and clumsy. Leonard Tinnan, a manager at NAA, wrote that "in comparing parachute or other so-called 'simple' means of booster recovery with the 'sophisticated' fixed-wing approach, for example, it becomes rather easy to demonstrate that the former is economically superior-if the time and costs associated with the mid-ocean retrieval and refurbishment of booster stages, and the impact of corresponding extension of turnaround time, are omitted or minimized. In the final analysis, however, all such factors must be fully considered." 36
A review of design concepts of the early 1960s shows that engineers were of two minds on approaches to reuse. The prospect of aircraft-type operation tantalized a number of these people, with the X-15 offering inspiration by flying routinely in flight test. Designers expected that their reusable launch vehicles would fly often. For this they would need wings and runways because recovery at sea would hamper frequent flight schedules. Other investigators wanted reusable launchers that would carry far more payload than a Saturn V. Far too large for wings, such leviathans would have to come down in the ocean.
Perhaps the largest of these reusable launchers was the Nexus. The work of a group at General Dynamics led by Krafft Ehricke, the Nexus was to represent the next leap beyond the Saturn V, carrying up to eight times more payload. Fully fueled, it would weigh 24,000 tons, as much as an ocean-going freighter. It would carry a 1,000 tons to orbit, allowing it to launch a spaceship bound for Mars. This behemoth would have a diameter of 202 feet with its height approaching that of the Washington Monument. It would fly as a single-stage launch vehicle. Fully recoverable, it would touch down in the ocean following a return from orbit. Parachutes would slow its descent. Retro-rockets, firing during the last seconds, would assure a gentle landing. 37
Others hoped to develop new types of engines. The years since World War II had brought enormous advances in turbojets, rockets, and ramjets. By 1960, all three offered tested paths to high-speed flight. With such further developments....
 ....in the offing, advocates of advanced propulsion saw their prospects in two novel concepts: LACE (Liquid Air Cycle Engine), an airbreathing rocket; and the scramjet, a hypersonic jet engine.
LACE sought to overcome the requirement that a rocket must carry its oxygen as a heavy quantity of liquid in an onboard tank. Instead, this concept sought to allow a rocket to get its oxygen from air in the atmosphere. Because rocket engines operate at very high pressure, no air compressor could compress the ambient air so as to allow it to flow into a thrust chamber. If the air could be liquefied, however, it would form liquid air, which could be pumped easily to high pressure. LACE sought to do this by passing the incoming air through a heat exchanger that used supercold liquid hydrogen, chilling the air into liquid form. The engine then would use the hydrogen and liquefied air as propellants. 38
This approach drew strong interest at Marquardt Co., a Los Angeles propulsion-research firm. In tests at Saugus, California in 1960 and 1961, Marquardt engineers successfully demonstrated a LACE design that used heat exchangers built by Garrett AiResearch. A film of those tests, shown at a conference of the Institute of the Aeronautical Sciences in March 1961, shows liquid air coming down in a torrent, as seen through a porthole. Marquardt went on to operate test engines with thrusts of up to 275 pounds. During these tests, LACE performed twice as well as conventional hydrogen-fueled rockets.
There were further innovations as well. Four-fifths of air is nitrogen, which does not burn. The presence of this nitrogen reduced the performance of LACE by cooling the exhaust and demanding extra liquid hydrogen to accomplish liquefaction. Oxygen, however, liquefies at 90 degrees Kelvin while nitrogen liquefies at the lower temperature of 77 degress Kelvin. Thus, by carefully controlling the heat-exchange process, oxygen in the air could be liquefied preferentially. This represented a topic for further research. In 1967, at General Dynamics, a test of this concept demonstrated 90 percent effectiveness in excluding the nitrogen. 39
While LACE represented a new direction in rocket research, the scramjet represented advances in the design of the ramjet. Ramjet engines showed their power during the 1950s when the Lockheed X-7, an unpiloted missile,  reached Mach 4.31 or 2881 miles per hour setting a record for the flight of airbreathing engines.40 This was close to the speed limit of a ramjet. Air in such a ramjet, flowing initially at supersonic speeds, had to slow to subsonic velocity in order to burn the fuel. When it slows, an engine becomes hot and loses engine power.
For a ramjet to reach speeds well beyond Mach 4, this internal airflow would have to remain supersonic. This would keep the engine cool and prevent it from overheating. This also imposed the difficult problem of injecting, mixing, and burning fuel in such a supersonic airflow. Nevertheless, a number of people hoped to build such an engine, which they called a scramjet. 41
Scramjet advocates included Alexander Kartveli, the vice president for research and development at Republic Aviation, and Antonio Ferri, a professor at Brooklyn Polytechnic Institute. During World War II, Ferri had been one of Europe's leading aerodynamicists and had directed Italy's premier research facility, a supersonic wind tunnel. Kartveli was one of America's leading airplane designers, crafting such fighter aircraft as the F-84 and the F-105. During the 1950s, his focus was on another proposed fighter, the XF-103 that was to use a ramjet to reach speeds of Mach 3.7 (2450 mph) and altitudes of 75,000 feet. 42
Ferri, who worked as a consultant on this project, formed a close friendship with Kartveli. They complemented each other professionally; Kartveli studying issues of aircraft design, Ferri emphasizing the details of difficult problems in aerodynamics and propulsion. As they worked together on the XF-103 they each stimulated the other to think bolder thoughts. Among the boldest put forth first by Ferri, and then supported by Kartvelli with more detailed studies, was the idea that scramjet-powered aircraft would have no natural limits to speed or performance. They could fly to orbit, reaching speeds of Mach 25. 43
In the Air Force, concepts such as LACE and scramjets drew support from Weldon Worth, technical director at the Aero Propulsion Lab of Wright-Patterson Air Force Base. Beginning in about 1960, Worth built up a program of basic research called Aerospaceplane. Not aiming at actually building an  airplane that would fly to orbit, the program pursued design studies and propulsion research that might lead to such aircraft in the distant future. The propulsion efforts were often very basic. When, in November 1964, Ferri succeeded in getting a scramjet to deliver thrust, it was impressive enough to merit an Air Force news release. Ferri went on to set a goal of 644 pounds of thrust for his test engine; he managed 517 pounds, 80 percent of his goal. 44
Aerospaceplane was too hot to keep under wraps. As a steady stream of leaks brought continuing coverage in the trade magazine Aviation Week. 45 At the Los Angeles Times, the aerospace editor Marvin Miles developed his own connections, which led to banner headlines: "Lockheed Working on Plane Able to Go Into Orbit Alone"; "Huge Booster Not Needed by Air Force Space Plane."46 The Air Force's Scientific Advisory Board (SAB) was not amused. As early as December 1960, it warned that "too much emphasis may be placed on the more glamorous aspects of the Aerospaceplane resulting in neglect of what appear to be more conventional problems."
By 1963, with hype outrunning achievement, the SAB had had enough. In October, it declared that "today's state-of-the-art is inadequate to support any real hardware development, and the cost of any such undertaking will be extremely large.... [T]he so-called Aerospaceplane program has had such an erratic history, has involved so many clearly infeasible factors, and has been subjected to so much ridicule that from now on this name should be dropped. It is also recommended that the Air Force increase the vigilance that no new program achieves such a difficult position." 47 Soon after, the Aerospaceplane died as a formal program. The scramjet, however, continued to live as NASA-Langley pursued an experimental program, the Hypersonic Research Engine that continued well into the 1970s. 48
Amid the gigantism of the Nexus and the far-out futurism of Aerospaceplane, there were those who were content to envision winged craft powered by conventional rocket engines. Here, too, the exuberance of the day  sometimes found expression in concepts of heroic size, such as the Astroplane of Aerojet-General. This concept included wings that would carry liquid hydrogen, much as the wings of airliners carry jet fuel. The Astroplane would have a wingspan of 423 feet and a length of 260 feet, excluding its payload. Carrying up to 220 tons of cargo, it would weigh 5000 tons at liftoff, and would rise into the air with twice the thrust of a Saturn V. 49
There were several design exercises, however, that projected modest size and short-term technology. One such concepts, the Astro from Douglas Aircraft, was a two-stage fully-reusable launch vehicle with payload of 37,150 pounds. Both stages of the Astro were designed as lifting bodies and would burn hydrogen and oxygen, using rocket engines that were already under development. The project engineers saw no problem with reuse of such rockets, noting that one of their engines, the Pratt & Whitney RL-10, had already "been operated more than 9000 seconds with more than 50 restarts."
Nevertheless, these engineers also shared the enthusiasm of the times. Written in 1963, their paper on the Astro anticipated that this vehicle could be operational "in the 1968-70 period." Each flight would cost $1.5 million. In readying the second stage for a reflight, turnaround time "would range between 2.5 and 5 days, based on a two-shift operation." The Astro would fly 240 times per year. 50
The era's exuberance was understandable; it had taken less than 35 years to advance from Lindbergh in Paris to astronauts in orbit. It was expected that this pace would continue. Amid the plethora of new possibilities, however, promising ideas sometimes were lost in the shuffle. This happened to Martin Marietta's Astrorocket concept of 1964. In the light of subsequent events, the concept seems to have offered a glimpse of the future, not only because the design was highly futuristic but because it clearly foreshadowed a class of design concepts that later stood in the forefront between 1969 and 1971.
With a planned liftoff weight of 1250 tons, Astrorocket was to be intermediate in size between the Saturn I-B and the Saturn V. It was a two-stage fully-reusable design, with both stages having delta wings and flat undersides. These undersides fitted together at liftoff, belly to belly. The designers of Astrorocket were no clairvoyants; rather they drew on the background of....
....Dyna-Soar and studies at NASA-Ames of winged re-entry vehicles. 51 The design studies of 1969-1971 followed the same approach, calling for two-stage fully-reusable configurations and a strong preference for delta wings.
Unfortunately, Astrorocket was at least five years ahead of its time. It failed to win support from NASA, the Air Force, and even its own designers, the management of Martin Marietta. That firm would continue to pursue studies of reusable launch vehicles, but these would not be Astrorockets.
"Let a hundred flowers bloom, let a hundred schools of thought content," said China's Chairman Mao in 1956.52 Studies of future space transportation were certainly blossoming. The field, however, needed vigorous pruning to define the most promising approaches. Weilding their garden shears, a number of investigators began to address some key questions.
Was it worth waiting for the scramjet? While its performance far surpassed that of even the best rockets, its development would take time and its prospects were not certain. Even accepting that the next generation of launch vehicles would continue to use rockets, there was the question of whether  such craft should take off horizontally, like an airplane. A booster, heavy with propellant, would need large, massive wings to do this. The vehicle, however, might ride a rocket-powered sled that would accelerate to several hundred miles per hour, at no cost to the booster in onboard fuel.
In 1962, NASA-Marshall set out to address such issues through design studies. The first step was to set standards for the design of launch-vehicle concepts. Each concept had to carry ten passengers or ten tons of cargo. Aircraft-type approaches were paramount, with Marshall stating that contractor designs "should be compatible with a philosophy used in the development of supersonic commercial jet aircraft and should offer a potential commercial application in the late 1970s, such as operating the vehicle over global distances for surface-to-surface transport of cargo and personnel."
This study, called "Reusable Ten Ton Orbital Carrier Vehicle," awarded contracts of $428,000 to Lockheed and of $342,000 to NAA. From June 1962 to December 1963, designers looked at two-stage fully-reusable configurations that put fixed wings on both stages, and carried through separate designs for both vertical and horizontal launch. They also considered concepts that drew on the Air Force's Aerospaceplane, with advanced airbreathing engines to provide propulsion in the first stage.
Subsequent studies investigated additional alternatives and pursued design issues in greater depth. In 1965, General Dynamics defined a concept for a reusable second stage that had the shape of a lifting body; both that firm and Lockheed conducted studies of first stages that could carry such a second stage. First-stage concepts continued to cover both vertical and horizontal launch. When using airbreathing engines, design choices ranged from conventional turbojet engines to scramjets. At General Dynamics the possibilities included LACE, for which that company had an active experimental program.
These studies concluded that, without exception, rocket engines were preferable to airbreathers for first-stage propulsion. A leader in these efforts, Max Akridge of NASA-Marshall wrote that "the economic advantage for the rocket engine was always about the same as the developmental cost of the airbreathing engine." Similarly, vertical takeoff proved to offer an advantage over horizontal launch because the cost of developing a rocket sled was not offset by lower weight and cost in the flight vehicle.
These studies defined the preferred approach of NASA-Marshall's Future Projects Office which called for a two-stage fully-reusable launch vehicle,...
....with both stages having fixed wings and rocket propulsion. The work also established the technical feasibility of such vehicles. NASA's Manned Spacecraft Center also adopted this approach, and NASA as a whole proceeded to hold to such designs until 1971. 53
A dissenting word came from the Air Force, where people were in no hurry to define a single class of concepts. At Wright-Patterson Air Force Base, the Flight Dynamics Laboratory emerged as a center for such studies. The FDL, conducting two design exercises during 1965, drew the interest of the Aeronautics and Astronautics Coordinating Board, a joint NASA-Air Force committee. In August 1965, this board set up a subpanel that spent the next year reviewing technology and design concepts for reusable launch vehicles. The subpanel issued its report in September 1966.
Rather than focus on a single type of craft, the subpanel took the view that advancing technology would permit increasingly capable designs to emerge  in the relatively near future. By 1974, the nation might have a vehicle, called Class I, in which a small reusable spacecraft would ride atop an expendable booster. The Saturn I-B could serve as this booster; Martin Marietta's proposed Titan III-M was another possibility, as was a new booster derived from the 260-inch solid rocket motor that was then under development. Essentially, the spacecraft would be tantamount to an updated version of the Dyna-Soar. In turn, two-stage fully-reusable configurations (counted as Class II), such as those of NASA-Marshall, could be available by 1978. By 1981, the prospects could broaden to include Class III, featuring horizontal takeoff and a first stage powered by scramjets.
Like others in the field, the authors of this report were optimistic. NASA's eventual space shuttle would fall into Class I, with two solid boosters, an expendable propellant tank, and a reusable orbiter. However, it would not fly until 1981, the year in which this subpanel expected to see an operational scramjet. Nevertheless, the work of this subpanel was significant for three reasons.
It brought reusability into the realm of ongoing collaborations between NASA and the Air Force. It was a reminder that development of a new Dyna-Soar was a quick route to reusability. In addition to this, in the words of the report's summary, "It is important to note that no single, most desirable vehicle concept could be identified by the Subpanel for satisfying future DoD and NASA objectives." The Air Force would not follow the lead of NASA-Marshall by focusing attention on a single design approach; the hundred flowers would continue to bloom. 54
Two Leaders Emerge: Max Hunter and George Mueller
While many were talking about airline-type space operations, few had the professional background that would allow them to do much about it. Most managers and senior designers had entered the realm of space flight by way of the Pentagon's missile program of the 1950s. Few of them had working knowledge of the standard methodology for determining the operating costs of commercial airliners, as published initially in 1940 and subsequently adopted by the Air Transport Association.
 At Lockheed Missiles and Space Company, Max Hunter was one of the few people in the industry with an intimate knowledge of both airline economics and of launch-vehicle design. Earlier in his career, working at Douglas Aircraft, he had spent two and a half years dealing with the performance of transport aircraft. In those days, Douglas ruled the skies with its DC-6 and DC-7 airliners. For some time, Hunter was in charge of all calculations on their performance and economics. He then joined the Thor missile project and served as chief design engineer. Rebuilt with upper stages, the Thor became the Delta launch vehicle and emerged as NASA's most widely used booster.
This background allowed Hunter to approach the problem of low-cost space transportation from a fresh perspective. Existing studies left him dissatisfied; he writes that "by the end of 1963 the state of recoverable rockets was terrible." He disliked two-stage fully-reusable concepts which to him meant building two vehicles to do the work of one, with the smaller of the two-the second stage-being the one that counted. He also felt that the technology of scramjets or single-stage-to-orbit concepts lay far in the future. By March 1964, however, he had the germ of a new idea: the stage-and-a-half configuration.
This new idea was to consist of a reusable core fitted with large expendable tanks that would hold most of the propellant. The core would carry everything that was costly and important: phe work of his fellow visionary Arthur C. Clarke. In 1945, Clarke proposed building communications satellites in geosynchronous orbit, at an altitude of 22,300 miles. They would circle the earth every 24 hours, to remain fixed in position in the sky:
Using material ferried up by rockets, it would be possible to construct a "space-station" in such an orbit. The station could be provided with living quarters, laboratories and everything needed for the comfort of its crew, who would be relieved and provisiayload, crew, engines, electronics, onboard systems. With a heat shield on its underside, it would achieve complete reuse. The tankage would consist of simple and inexpensive aluminum shells that would carry liquid hydrogen and liquid oxygen. They would fall away during the ascent to orbit, leaving the core to continue with the mission.
Hunter went to work at Lockheed in the fall of 1965. On his first day, he was asked if there was anything he thought should be done that was not being done already. He responded with an internal company memo on orbital transportation, which drew the attention of a number of senior managers. These included Eugene Root, the president of LMSC, who provided the internal company support that allowed Hunter to begin to pursue his ideas. He proceeded to take his gospel to meetings of professional societies, and won funding from the Air Force. He particularly emphasized that the economic model of the Air Transport Association, though developed for airliners, could apply as well to rocket transports.
 Paradoxically, two-stage fully-reusable vehicles promised launch costs as low as one-third of Hunter's approach-but only when flying up to a hundred times per year. Because it had a far lower development cost for 10 or fewer flights per year, the stage-and-a-half had a decided advantage. In Hunter's words, "its development can consequently be justified at an earlier point in time with a smaller number of missions." 55
While Hunter gave an airliner's view of airplane-type space operations, NASA's George Mueller, head of the Office of Manned Space Flight, was promoting such concepts as well. His domain included all of Apollo; he also was a strong proponent of space stations, and he was pushing vigorously for a strong Apollo Applications program. Looking to the future, he understood that low-cost space flight would be essential for viable space stations.
As a first step, in December 1967, he invited a number of NASA and industry specialists to a one-day symposium, held in January at NASA Headquarters. Because much of the data from industry was proprietary, Mueller limited attendance to representatives of government agencies. Even so, some 80 people, most of them from NASA and the Air Force, attended the conference. The symposium proceedings give a clear view of the topic at the end of 1967, when the field was alive with ideas but when no single design approach had come to the forefront. In addition to this, those proceedings presented design solutions that, four years later, would show up in the final space-shuttle configuration.
Martin Marietta was the most conservative, pitching its Titan III-M along with a small reusable spacecraft, similar to the Dyna-Soar, that would carry six people. This was the quintessential Class I design (featuring an expendable booster) that NASA and the Air Force had identified in their 1966 joint study. The Titan III-M was to rely on twin 120-inch solid boosters, slightly smaller than the solid rockets that, 13 years later, would boost the operational Space Shuttle.
Those rockets were not built as single units, but rather as a stack of segments, like short lengths of pipeline that are bolted together at their flanges. Manufacturers such as Thiokol filled each segment with the solid propellant, then sent them off by highway or railroad. Such segmented rockets were much easier to transport than the unsegmented type; the segments could be stacked and joined at the launch site, using putty to fill the gaps.
The standard Titan III-C used five-segment solid rockets, each 85 feet long with a thrust of 1,180,000 pounds. For the Titan III-M, these rockets were to grow to seven segments, each 112 feet in length with a thrust of 1,508,000 pounds. The first stage was also to grow in length, to hold more propellant, while receiving liquid-fueled engines with 11 percent more thrust. The combination would carry 38,000 pounds to orbit from Cape Canaveral, or 32,000 pounds from Vandenberg Air Force Base. 56
Lockheed presented Max Hunter's configuration. Called Star-Clipper, it featured a core vehicle in the form of a lifting body, triangular in shape. The expendable propellant tanks would be 156 inches in diameter (the limit for highway or rail transport) and would join at the front, running along the sides of the core. The vehicle's avionics would include an automated  on-board checkout system, similar to those on airliners. Lockheed managers claimed that the Star-Clipper could lift off within one hour after arrival at the launch pad. 57
McDonnell Aircraft, recently merged to form McDonnell Douglas, had built the piloted Mercury and Gemini spacecraft, and had been studying new launch-vehicle concepts for six years. Like Lockheed, it had adopted the stage-and-a-half approach, again with a reusable core flanked by expendable propellant tanks. Known as Tip Tank, this concept would carry 12 astronauts, sitting side by side like passengers in first class. The core again had the shape of a lifting body, but McDonnell went one better than Lockheed by proposing to add small wings that would fold within the fuselage and snap out for use in landing. These wings then would help the craft to handle better during the landing approach, when conventional lifting bodies tended to dive toward a runway at speeds of several hundred miles per hour. 58
The Lockheed and McDonnell Douglas concepts counted as only partially reusable, because their external tanks would not be recovered. During 1971, this became the configuration NASA would adopt; the shuttle orbiter would take shape as a core vehicle of the type Hunter had recommended. Its propellants would go into a big expendable tank, with two large solids flanking this tank in the fashion of the Titan III-M. Hence as early as 1967, the basic elements of the eventual shuttle not only were well known but had influential advocates among NASA's contractors.
At that early date, however, there was no reason to pick this approach over others that also had their advocates. The two-stage fully-reusable concept continued to shine, and General Dynamics, with Air Force support, had been studying a version called the Triamese. It would feature a standard vehicle fitted with rocket engines and a pilot compartment. Like the core of McDonnell Douglas' Tip Tank, it was tantamount to a lifting body with deployable wings. Three such vehicles, identical in shape, would fit together to make a complete launch system. The middle vehicle would carry the payload and would serve as the core; the other two would serve as tankage, carrying most of the propellant. This standardization represented an attempt to save money during development, for then it would not be necessary to....
.....develop a reusable first stage with a design of its own. In the Triamese approach, all three vehicles would reenter and return to a runway. 59
General Dynamics did not present this concept at Mueller's symposium, but instead discussed five alternatives, ranging from the Titan III-M to a two-stage fully-reusable configuration. The company showed, again, that the former had a low development cost but a high cost per flight; the latter had the highest development cost but the lowest per-flight cost. Though these conclusions were not new, they too pointed a path to the future.
These conclusions addressed the issue of designing a reusable launch vehicle to meet economic criteria. If the criterion was to achieve the lowest possible cost per flight, thus attaining true airline-like operation, then one would go with the two-stage fully-reusable, even though this approach carried high development cost. If the most important goal was to achieve minimum development cost, then one would choose the Titan III-M. Stage-and-a-half configurations appeared intermediate, both in development and in launch costs. In sum, one could choose a level of reusability so as to balance between these two types of cost. As its Space Shuttle concepts matured, it is doing precisely this that NASA would spend much of 1971.
 The General Dynamics presentation offered more. Within the industry, it was widely appreciated that piloted aircraft cost much less to develop than missiles or expendable launch vehicles. The reason was that missiles demanded extensive and costly ground tests to assure that they would fly properly, with no pilot at the controls. By contrast, the development of aircraft took full advantage of their reusability. Test pilots could start with simple exercises in taxying and takeoff, then reach toward higher speeds and greater levels of performance, in step-by-step programs. At each step, the aircraft would come back, where engineers could study it carefully and correct deficiencies. Such flight testing was far less costly than ground tests.
General Dynamics then drew on recent experience with the X-15 and the Atlas ICBM, arguing that piloted craft could maintain this advantage even as rocket-powered vehicles of extreme performance. The X-15 and Atlas had both gone through development in the late-1950s; their empty weights were similar, and both mounted rocket engines that came to their respective contractors as government-furnished equipment. Although the X-15 was more complex than Atlas, it had less than half the development cost because it too followed the step-by-step approach to flight test, with its test pilots often taking action to save the vehicle from disaster. Indeed, the X-15 would likely have been destroyed on as many as a third of its flights had there been no pilot aboard. 60 Test pilots thus served as inexpensive substitutes for the automated systems that might have been required to take their place.
The reusable concepts of the day, and those that followed during 1968 and 1969, were often referred to as Integral Launch and Reentry Vehicles. The Air Force, in particular, used that designation in its own work.61 Mueller adopted a different term, calling such vehicles space shuttles. The term had appeared now and then through the years. For example, Philip Bono of Douglas Aircraft had offered a concept called the ROMBUS (Reusable Orbital Module, Booster, and Utility Shuttle). Dating to 1963, it resembled the immense Nexus, and its mission was similar. Walter Dornberger, who had proposed to build Bomi during the 1950s, lately had been writing of a "recoverable and reusable space transporter, or shuttle." He described it as "an economical space plane capable of putting a fresh egg, every morning, on the  table of every crew member of a space station circling the globe." Mueller now made the term his own, fully aware that the space shuttle was to shuttle to and from such a station.
In August 1968, in London, he received an award from the British Interplanetary Society and gave a prepared address in which he pledged his troth to the shuttle as NASA's next goal:
This was not your usual speech by a government official. Napoleon may have spoken often of "destiny," but even within NASA, an agency not known as a home for shrinking violets, such talk was slightly out of the ordinary at least. It helped that Mueller was talking to his fellow enthusiasts and was speaking in London, where his presentation was not likely to receive hostile fire from the Washington Post. Mueller's hopes, however, contrasted sharply with recent experience, wherein NASA had tried and failed to define an ambitious Apollo Applications effort as a major post-Apollo program. The agency's budget was on a sharp downhill slide, and NASA was nowhere near the bottom. Indeed, it had not begun to see the bottom.
NASA and the Post-Apollo Future
Before federal bureaucrats such as Mueller could grapple with human destiny, they first had to face the more prosaic question of what NASA would do after landing astronauts on the moon. The first significant interest in this issue came in January 1964, when President Johnson, in office for barely two months, sent a letter to NASA Administrator James Webb.
The background to this letter involved a program of the Atomic Energy Commission called NERVA (Nuclear Engine for Rocket Vehicle Application) that was developing a nuclear-powered rocket engine. While NASA did not....
....need it for Apollo, such an engine might prove useful indeed in any follow-on program of piloted flight to Mars. The program had strong support from Senator Clinton Anderson (D-New Mexico), chairman of the Senate space committee; it also had the support of Webb. Its opponents, however, included President Kennedy's science advisor, Jerome Weisner. Weisner convinced Johnson to ask NASA to identify the future missions that would require NERVA's power.
Johnson took up this and other issues in his letter to Webb. Could NASA list possible space objectives beyond those already approved? What supporting research and development would these new goals require? How much of NASA's current work, particularly in the development of launch vehicles such as the Saturn V, could support such future programs?
An old hand at Washington politics, Webb smelled a rat. He later described this as "part of a power play rather than a desire for proposals. It  was an effort to put us on the defensive and to make us commit ourselves to certain missions which they could then attack." Accordingly, Webb did not reply immediately, but set up a committee that proceeded to take its sweet time in preparing a response. Meanwhile he mollified Johnson with interim replies, listing possible future missions but declining to choose among them. 64
Events that summer showed that Webb was wise to be cautious. As far back as 1962, the Future Projects Office at NASA-Marshall had contracted with several major aerospace firms for initial studies of piloted planetary missions, including landing on Mars. These studies continued during subsequent years. Then, in mid-1964, the new presidential science advisor, Donald Hornig, asked Webb to present an estimate of the cost of a piloted Mars landing that might follow Apollo.
The initial estimate, internal to NASA, was $32 billion. An internal review added $5 billion for program contingencies and forwarded the total of $37 billion to Webb. He accepted some further additions that hiked the cost to $50 billion, and gave this figure to Hornig. Hornig doubled it to $100 billion, on his own initiative, and gave this new estimate to a Congressional committee. The next day, newspapers quoted one congressman as stating that the piloted Mars mission would cost $200 billion, amounting to 40 years of NASA's budgets at the 1965 rate of $5 billion per year. In the words of an observer, "In only one week, a well developed estimate of $37 billion was multiplied into a $200 billion program." 65
A year after receiving his initial request, Webb finally gave a full reply to Johnson's letter in a report written in February 1965. It amounted to a verbose exercise in saying little that was new or significant and saying it at considerable length, while offering no targets for skeptics. The report reviewed recent and current NASA activities in detail, and included three single-page lists of future possibilities. These lists resembled pages from a book index, lacking any trace of description, estimated cost, schedule, or priority. In an outstanding display of political adroitness, the report called for "a continued balanced program" that would "not impose unreasonably large demands upon the Nation's resources." No one could oppose such recommendations; they were on a par with supporting motherhood and apple pie.
 Webb's report drew questions within the Senate space committee, which complained that "alternatives are presented, but no criteria are given as to how a selection would be made." That was just as Webb intended; he was not about to take the initiative in offering a plan that critics could attack. He would have been quite willing to have the President take the lead, as Kennedy had done in supporting Apollo in 1961. Johnson, however, also preferred to keep his options open. In March 1965, he told his advisor Jack Valenti that he did not intend to make a new Kennedy-style commitment in space: "I think I would have more leeway and running room by saying nothing, which I would prefer." 66
The historian Arthur Levine notes that two years later, Webb explained to him just why he had finessed Johnson's initial request:
 The last point addressed the fact that there was no consensus, even within NASA itself, as to NASA's next goal. George Mueller, head of the Office of Manned Space Flight, had his eye on a piloted mission to Mars. The two most powerful center directors, Von Braun at NASA-Marshall and Robert Gilruth of the Manned Spacecraft Center, preferred a different objective: a space station. Mueller also liked space stations and was well aware of their usefulness as preparations for Mars. Von Braun and Gilruth, however, saw space stations as major elements of a program that, diverging sharply from one that would aim at Mars, would focus on activities in Earth orbit.
Nevertheless, during 1965 and 1966, the beginnings of a post-Apollo future began to take shape. Not surprisingly, its major features were in line with the initiatives that Webb had suggested in his report to Johnson. Apollo Applications emerged, strongly backed by Mueller. For Mars, attention focused on an ambitious automated mission called Voyager that would orbit that planet and then send craft to land on its surface, looking with instruments for signs of life. Plans for Voyager flourished for a time. While initial designs called for use of the Saturn I-B, in October 1965 its officials decided instead to try for the much larger Saturn V. 68
In addition to this, even though Webb was unwilling to carry through a serious plan for NASA's future, the President's Science Advisory Committee (PSAC) proved willing to do it for him. This blue-ribbon panel was potentially a source of clout; it operated within the Executive Office of the President, and received support from another White House group, the Office of Science and Technology. In February 1967, the PSAC issued a major report, The Space Program in the Post-Apollo Period. John Newbauer, editor of the trade journal Astronautics & Aeronautics, wrote that it "should prove the pivot for policy discussions for some time to come." He described it as "the most cohesive and solid appraisal of space-program goals since the Space Act itself," which led to the founding of NASA in 1958. 69
The PSAC report did not endorse anything so specific as piloted flight to Mars. Nevertheless, it proposed an organizing theme: "a program directed ultimately at the exploration of the planets by man." The report defined this as "a  balanced program based on the expectation of eventual manned planetary exploration." The program would pursue several intermediate goals including continued lunar missions by astronauts; long-duration piloted flights, at first through Apollo Applications and later in a true space station; and "a strongly upgraded program of early unmanned exploration of the nearby planets."
The PSAC was certainly not in NASA's pocket; its report pulled no punches. It criticized the Apollo Applications wet workshop: "some doubts arise about man's ability to carry out extensive construction efforts in space. The requirement that man actually construct his laboratories in space in these initial applications may constitute a serious impediment to their development." A true space station might represent "a more effective use of funds." The panel endorsed building a single wet workshop, if only as an initial step: "The launch vehicle and spacecraft for this experiment are already on order, and the opportunity for 28- and 56-day flights in 1968 should be taken."
In other areas, the report was more favorable: "In the period after the initial two Apollo lunar landings we recommend that a sustained program of lunar exploration... continue manned expeditions at the rate of between one and two per year." The PSAC recommended "that the Saturn V vehicle continue to be produced," and that "the post-Apollo Saturn V production rate be fixed at 4 systems per year."
On Voyager: "We recommend an expanded commitment to the Voyager planetary lander program, pointing toward a soft landing of a Surveyor-type module on Mars in 1973." As a prelude to Apollo, a program called Surveyor was seeking to conduct soft landings of automated spacecraft on the moon, and had scored its first success the previous June.
On a space station:
On future launch vehicles:
The report did not give NASA everything it might have wanted, even in dealing with projects that were achievable in the short-term. It endorsed only a modest Apollo Applications effort, as noted. It ignored NERVA, though that program was proceeding smartly with its nuclear engine and offered a promising source of propulsion for a piloted mission to Mars. The PSAC also recommended delaying a commitment to a true space station until 1971 or 1972, although its advocates hoped for such a decision as early as 1968. 71 By endorsing construction of this station "in the mid-1970's," and by openly embracing Mars as a long-term goal, the PSAC endorsed a program that went well beyond what NASA in fact would be able to pursue.
While Mars was in the ascendancy at the PSAC, NASA's hopes were about to prove star-crossed. The agency had been charging ahead with Apollo; in January 1967 it had a Saturn I-B on a pad at Cape Canaveral that was being readied to launch a mission into orbit. Late that month, the astronauts Gus Grissom, Ed White, and Roger Chaffee were conducting a pre-launch exercise atop that rocket, within their spacecraft. A fire broke out; the men could not escape, and they perished before help could reach them. 72
In the aftermath of this fire, plans for the future went on hold while NASA struggled to win success with Apollo. There also was bad news elsewhere in Washington and in the nation. In January, the President had presented the federal budget for Fiscal Year 1968, anticipating a deficit of $8 billion. The Vietnam War, however, was escalating rapidly. By August, when the estimate was close to $30 billion, Johnson asked Congress to approve a 10 percent income-tax surcharge to keep it from rising further.
The summer of 1967 also brought major riots. Looters in Newark plundered stores on a massive scale; snipers fired from rooftops, and fires blazed high. The city's 1,400 police officers could not control the situation. Speaking  of "a city in open rebellion," New Jersey's governor called in the National Guard. At the peak, almost half of the city was in the hands of the rioters. The upheavals raged for five days; 27 people lost their lives.
Detroit blew a week later; the next 11 days saw 1,600 fire alarms. Three miles of Grand River Avenue, a major thoroughfare, burned to the ground. Some sections of downtown resembled the burned-out German cities of World War II. Forty-three people died; over 7,000 were arrested; 5,000 were left homeless. 73
"Conditions have greatly changed since I submitted my January budget," the President admitted. "Because the times have placed more urgent demands upon our resources, we must now moderate our efforts in certain space projects." In the House, an appropriations subcommittee reopened hearings on the NASA budget, and proceeded to make deep cuts in virtually every program except Apollo.
With cities burning, taxes rising, and the Vietnam War escalating, NASA proceeded to shoot itself in the foot. In a stunning display of tactlessness, the Manned Spacecraft Center invited 28 companies to bid on a study of piloted flyby missions to Mars and Venus, beginning in 1975. When this announcement created an uproar, MSC withdrew its request. It was too late. In Congress, the view took hold that the automated Voyager project should be canceled because it was the first step toward a needless extravagance: a piloted mission to Mars.
The final cut in NASA's budget came to $511 million, a reduction of 10 percent. Voyager was canceled, being eliminated in conference with the Senate. Apollo Applications, budgeted at $454 million in the January presidential request, ended with $253 million. The conferees spared Apollo, voting funds to allow this program to recover in the wake of the fire at Cape Canaveral. The cuts, however, hit hard at future programs. 74
Voyager did not remain dead for long. Within days of its formal cancellation, NASA officials began discussing a follow-on concept that was approved by the president in the budget for FY 1969. The new project had the name Viking, and its mission remained the same: to orbit Mars with automated spacecraft, place landers gently on the surface, and look for signs of  life. Viking, however, would not ride a Saturn V; it would use the Titan III-Centaur. While this was certainly a splendid launch vehicle, it had less than one-eighth the lifting power of its much larger cousin. 75
That summer's near-debacle confirmed Webb's belief that even a modest post-Apollo planning effort could backfire badly. With Apollo continuing to reign supreme in a time of cutbacks, Webb took to raiding the Apollo Applications budget by reprogramming some of its funds. In June 1968, he told his center directors that this program was nothing more than "a surge tank for Apollo." In this fashion, he took from the future to meet the needs of the present. Above all else, Apollo had to succeed. 76
That program's peak funding had come in FY 1965. That year also saw NASA's appropriation peak at $5.25 billion. After this, the budget slid downward; the appropriation for FY 1969, which began the previous July, was $3.953 billion, a drop of 25 percent. NASA's in-house employment stayed close to the FY 1965 level of 33,000 positions. The contractors, however, were having a hard time of it; their personnel had fallen by half, from 377,000 to 186,000. 77 Unless NASA could take hold of something new and major, it was likely to shrink to insignificance.
Mueller had hoped that Apollo Applications could come to the forefront as this new program. Already in 1968, it was clear that this would not happen. The Agency had spent several years trying to pursue such a route to the future, without success. More was involved here than budget cuts per se. Congress and the Administration had imposed those cuts because NASA had failed to make a persuasive case for its plans. In addition to this, NASA was not able to propose anything as compelling as Apollo.
Apollo, above all, had the beauty of simplicity. Everyone knew of science-fiction visions of astronauts on the moon. The program's goal was succinct: to carry out the lunar landing during the decade of the 1960s, and to bring its explorers back safely. As Von Braun stated in 1964, "Everybody knows what the moon is, everybody knows what this decade is, and everybody can tell a live astronaut who returned from the moon from one who didn't." 78
 Apollo Applications lacked this compelling character. In the end, it was a program with no clear central focus. It offered only modest initiatives: solar astronomy, flights with durations of weeks, medical studies, and opportunities to use Saturn-class rockets that otherwise might go to waste. The historian John Logsdon writes that, according to program critics, these initiatives "were designed to fit the specific features of the Apollo and Saturn hardware. The missions suggested were not necessarily those deserving highest priority, and modified Apollo/Saturn equipment was not necessarily the most effective way of carrying out those missions." Here was enough to support a single orbital workshop, but not enough to complete with something as historic as putting the first man on the Moon.
An opportunity, however, did exist to plan once again with boldness. The PSAC report had danced around this, proposing nothing more than "the expectation of eventual manned planetary exploration." That was not NASA's style; the agency had established itself by literally reaching for the moon, not by resting content with an expectation that astronauts would get there someday. The new goal was there for anyone who would dare to pursue it, to seize it. One could see it in the night sky, glowing redly; one could name this goal with a single word: Mars. During 1969, NASA would seek seriously to establish a piloted expedition to this planet as the basis for the agency's future.
1. Pierce, Beginnings, pp. 38-39.
2. Ley, Rockets, pp. 263-265.
3. Collier's, June 27, 1953, pp. 33-40.
4. Bernstein, Three Degrees, pp. 75-75, 91-95, 102-105; Pierce, Beginnings, pp. 1-9; New Yorker, September 21, 1963, pp. 60-66.
5. Emme, ed., History, p. 138; Thompson, ed., Space Log, Vol. 27 (1991), p. 50.
6. Ruffner, ed., Corona, pp. 3-39.
7. Ibid., pp. 16-24.
8. Richelson, Secret Eyes, p. 265.
9. NASA SP-4012, Vol. III, p. 27.
10. NASA SP-4208, p. 4; NASA SP-4206; see index references.
11. NASA SP-4208, p. 5.
12. Ibid., pp. 6-7; NASA SP-4012, Vol. II, pp. 54-58.
13. NASA SP-4208, pp. 20-21, 26-27, 53-55.
14. Ibid., pp. 36-37, 69-71.
15. Ibid., pp. 42-43; NASA SP-4011, p. 71.
16. NASA SP-4208, pp. 53, 86-87.
17. Ibid., pp. 105-109.
18. NASA SP-4012, Vol. II, p. 61.
19. NASA SP-4208, pp. 107-110, 112, 114-115.
20. Ibid., p. 353.
21. Ibid., pp. 107-108; Thompson, ed., Space Log, Vol. 27 (1991), p. 137.
22. Thompson, Space Log, Vol. 27 (1991), pp. 137, 138, 141; Vol. 31 (1995), p. 68.
23. NASA SP-4208, pp. 20-21.
24. Ibid., pp. 9-10; AAS History Series, Vol. 14, pp. 80-83.
25. Astronautics & Aeronautics, March 1967, pp. 34-46; NASA SP-4308, pp. 293-300.
26. Report D2-114012-1 (Boeing).
27. AAS History Series, Vol. 14, pp. 83-86.
28. NASA SP-4308, p. 294.
29. Astronautics & Aeronautics, November 1968, p. 54.
30. NASA budget data, February 1970; Science, 5 February 1971, p. 460.
31. NASA budget data, February 1970.
32. Serling, Legend, p. 186; Pedigree, p. 58.
33. Newsweek, January 2, 1961, p. 42.
34. Akridge, Space Shuttle, pp. 8-9; NASA SP-4012, Vol. II, p. 56.
35. Akridge, Space Shuttle, p. 9; Astronautics & Aeronautics, August 1968, pp. 50-54.
36. Astronautics, January 1963, pp. 50-56.
37. Astronautics & Aeronautics, January 1964, pp. 18-26.
38. Heppenheimer, Hypersonic, pp. 15-16.
39. Ibid., p. 16; Aviation Week, May 8, 1961, p. 119. Film courtesy of William Escher, Kaiser Marquardt, Van Nuys, California.
40. Miller, X-Planes, p. 72.
41. Heppenheimer, Hypersonic, pp. 12-14.
42. Ibid., pp. 10-12; Gunston, Fighters, pp. 184, 193-195.
43. Republic Aviation News, September 9, 1960, pp.1,5.
44. Heppenheimer, Hypersonic, pp. 14-17; Hallion, ed., Hypersonic, pp. 948-952; news release, USAF Aeronautical Systems Division, November 12, 1964. Scramjet test data from Louis Nucci, General Applied Science Laboratories, Inc., Ronkonkoma, New York.
45. Aviation Week: October 31, 1960, p. 26; December 26, 1960, pp. 22-23; June 19, 1961, pp. 54-62; November 6, 1961, pp. 59-61; April 23, 1962, pp. 26-27. See also Missiles and Rockets, May 22, 1961, p. 14.
46. Los Angeles Times: November 3, 1960, p. 3A; January 15, 1961, front page.
47. Hallion, ed., Hypersonic, p. 951.
48. Ibid., pp. 747-842; Heppenheimer, Hypersonic, pp. 17-20.
49. Astronautics & Aeronautics, January 1964, pp. 35-41.
50. Ibid., pp. 42-51.
51. Hallion, ed., Hypersonic, pp. 952-954.
52. Oxford, p. 328.
53. Akridge, Space Shuttle, pp. 5, 16-19; Aviation Week, March 26, 1962, pp. 20-21; Report LR 18790 (Lockheed); Report GD/C-DCB-65-018 (General Dynamics); Nau, Comparison.
54. Hallion, ed., Hypersonic, pp. 964-978; Ames, chairman, Report.
55. Hunter, Origins. Reprinted in part in Earth/Space News, November 1976, pp. 5-7.
56. Akridge, Space Shuttle, p. 35; Schnyer and Voss, Review, pp. 15-16, 40-47; Quest, Fall 1995, pp. 18-19; Astronautics, August 1961, pp. 22-25, 50-56.
57. Schnyer and Voss, Review, pp. 17-22.
58. Ibid., pp. 35-39.
59. Reports GDC-DCB-67-031, GDC-DCB-68-017 (both from General Dynamics).
60. Schnyer and Voss, Review, pp. 28-34; Astronautics, January 1963, p. 53.
61. Jenkins, Space Shuttle, p. 56; Hallion, ed., Hypersonic, p. 995.
62. Astronautics & Aeronautics, January 1964, pp. 28-34; November 1965, pp. 88-94.
63. Mueller, Address, August 10, 1968.
64. NASA SP-4102, p. 243; Logsdon, Apollo, Chapter 1, pp. 27-28.
65. AAS History Series, Vol. 17, pp. 421-429.
66. NASA SP-4102, p. 243; Jack Valenti to Lyndon Johnson, March 30, 1965 (Lyndon Johnson Presidential Library, Austin, Texas); Smith, chairman, Summary. Reprinted in NASA SP-4407, Vol. I, pp. 473-490.
67. Levine, Future, pp. 118-119.
68. NASA SP-4102, p. 147; Logsdon, Apollo, Chapter 1, pp. 17-18.
69. Astronautics & Aeronautics, March 1967, p. 20.
70. Ibid., pp. 20-22; Long, chairman, Space Program.
71. Logsdon, Apollo, p. I-32.
72. Ibid., Chapter 1, pp. 37-38; Chaikin, Man, pp. 11-26.
73. Logsdon, Apollo, p. I-46; Manchester, Glory, pp. 1079-1081.
74. Logsdon, Apollo, Chapter 1, pp. 46-47; NASA SP-4102, p. 148.
75. NASA SP-4012, Vol. III, pp. 27, 40-41, 213-219.
76. NASA SP-4208, pp. 86-87, 104; NASA SP-4102, p. 254.
77. NASA budget data, February 1970.
78. U.S. News & World Report, June 1, 1964, p. 54.
79. Logsdon, Apollo, p. I-26.