Chapter 3: Assembly
“The goal we have set for ourselves is the reduction of the present costs of operating in space from the current figure of $1,000 a pound for a payload delivered in orbit by the Saturn V, down to a level of somewhere between $20 and $50 a pound. By so doing we can open up a whole new era of space exploration. Therefore, the challenge before this symposium and before all of us in the Air Force and NASA in the weeks and months ahead is to be sure that we can implement a system that is capable of doing just that.”
With the arrival of the Constitution in the Vehicle Assembly Building to join the already-present S-IVC stage and the Space Shuttle Endeavour, the pieces were in place for the first operational Space Shuttle mission. The only task remaining was to fit them into their proper places in the stack, integrating them into a single assembly to prepare them for flight. It was a familiar task for the VAB technicians, and they set to work with their typical care and skill. This particular stack drew particular interest from visiting tourists and NASA engineers alike, but the attention was nothing new to the team which had less than a decade before prepared Saturn V moon rockets in these very same spaces. Now, descendants of those famous craft were being readied for a mission much closer to home--but no less important for the future of NASA's space exploration ambitions.
The assembly process began with the arrival of Crawler-Transporter 1, bearing on its back Mobile Launch Platform 3, which had been the first of the three MLPs to have its Launch Umbilical Tower modified to service the RS-IC Space Lifter. Under the eyes of a dozen directing technicians, the driver in the cab positioned the massive steel structure within High Bay 3, then gently lowered it onto the waiting support mounts. Technicians swarmed over the MLP, conducting the final checks of the hold-down mounts and service masts in preparation for the stacking process. Meanwhile, other technicians in High Bay 4, located across the transfer aisle on the west side of the building, worked around Constitution, still resting on her transport trailer beneath the five hundred foot ceiling. Not for much longer--the crews used the massive travelling cranes up in the rafters to position and mount two large yellow lifting fixtures to the nearly-747-sized vehicle. One mounted near the nose, just aft of the cockpit, supported by the new 325-ton crane added specifically for working with the RS-IC's bulk. The other, closer to the engines, was supported by the original Apollo-era 250-ton crane running on the same tracks. Technicians with torque wrenches worked their way around the lift fixtures, cross-checking the inch-thick mounting bolts for the fixtures. With that complete, the crews stepped back towards the walls, and while tourists looked on from the roped-off area in the transfer aisle, the overhead cranes took up the slack. Like a massive Harrier, the delta-winged booster lifted straight up off the transport rig--first a foot, then two, then ten, then thirty. With enough height, the two overhead crane operators almost 500 feet above worked a careful ballet at the direction of headset-wearing technicians on the ground. The 325 ton crane pulled in its lines, raising the RS-IC's nose as the 250-ton crane closed the distance between them, bringing the tail into line under the nose. Like a marionette on strings, the massive vehicle pirouetted and pointed its nose skywards, its wing-mounted tails clearing the floor by less than ten feet as its nose rose almost 200 feet into the air.
With the vehicle lifted to the vertical, the two overhead cranes worked together, lifting the booster up by its own length, clearing the cross-bracing of the VAB structure at the 160 foot level and twisting it slightly around its axis to clear its wings through the gap into the transfer aisle. Engineers watched with technicians and yet more tourists as the booster--the size of the Statue of Liberty--crossed overhead beneath the two cranes, moving directly across the transfer aisle and into the the waiting High Bay 3, supported only by the thick cables--made thin by distance. More than a few let out careful breaths as the booster was lowered back to the level of the MLP deck, carefully aligned by technicians, then finally lowered onto the launch hold-down mounts and secured. The tension abated almost palpably as the MLP took up the weight. With the move done, the cranes and their fixtures were detached and work platforms were lowered into place around the booster. The cranes went to work on the next tasks, moving the far lighter S-IVC stage into the transfer aisle, lifting it to vertical, and handing it off to the large overhead crane. With the aft skirt and interstage which would protect its engine already attached, the S-IVC was lowered onto the mounting points on the nose of the RS-IC. As yet more work platforms were swung out to access the S-IVC, the cranes went back for the final pieces: the 30-ton Space Shuttle and its adapter. Once lifted into position, the Shuttle crowned a stack that was almost 300 feet tall. The final set of work platforms were rotated into place to access the Shuttle, and the engineers and technicians of the VAB crew set to work finishing the job of checking out the integrated vehicle. Four days after the arrival of Constitution in the VAB, the stack was assembled. Now it needed to be tested and readied for flight.
With Presidential support secured for the Space Transportation System, NASA was able to line up several key trump cards behind the program, beginning in the oval office, moving down to supporters like Cap Weinberger at the Office of Management and Budget, and powerful Congressional interests from districts representing aerospace-heavy areas like California, Florida, Alabama, and Texas. It could also offer a vision for the future of space exploration directly endorsed by the President himself to follow the highwater marks of Apollo: a future where spaceflight might not be limited to the select group of military test pilots who in 1972 had so far landed on the moon, but scientists, doctors, blue-collar workers on space construction projects, teachers, reporters, and housewives. The vision of accomplishing missions in space in a cheaper, more cost effective way was a vision that was embraced to some extent by both space enthusiasts and space skeptics alike--though many of the latter still doubted if the savings of the vehicles depicted on paper could be achieved by vehicles built of metal. However, to see these plans tested, NASA would first have to move forward with translating these political successes into the reality of a new generation of manned spacecraft. The assembly of NASA’s centers and contractors behind the project and the division of responsibility for the vehicle began shortly after the President’s approval of the program.
The distinction between the parts of the Space Transportation System offered a natural break between the spheres of influence of the agency’s most powerful centers: the Space Lifter was the obvious province of Marshall Spaceflight Center in Huntsville, while the Space Shuttle glider became with little challenge the preserve of the Manned Space Flight Center in Houston. As with Apollo, Marshall would provide the rocket, while Houston would supply the vehicle, crew, and carry out the missions. This wasn’t the only connection to Apollo, however. It was assumed within many of the studies supporting the ISRS architecture that the booster would be derived from existing stages and tooling, and the result was a rapid--and largely pro forma--Request for Proposal being issued February 21, 1972 with all proposals due two months later on April 21. Boeing, the foremost industry advocate for ISRS and originator of many of the key concepts with their involvement in the INT-22 design studies of similar vehicles in the mid-60s, unsurprisingly submitted one of the strongest proposals for the Space Lifter booster. However, a surprisingly strong second submission came from North American Rockwell, who proposed to draw on their history with the X-15 (described in their proposal as the “first reusable suborbital rocketplane”) and the XB-70 Valkyrie Mach 3 bomber in the development of a Space Lifter derived not from the Saturn V first stage, but from its second stage, using the same ballasted, retro-boosting hot structure approach applied to the S-II stage that Boeing suggested to apply to the S-IC. However, NAR’s proposal was weaker in several areas, particularly development cost: the J-2 engines of the S-II would need to be replaced with new high-pressure engines like the proposed SSME, the VAB and MLPs would need to be more heavily modified to mount to the S-II at zero level, and other changes would cascade through the architecture. Thus, though North American’s proposal was rated quite highly, the contract was awarded in May to Boeing. Marshall and Boeing immediately set to work fleshing out the details of the design and arranging the evaluation of S-IC tooling which had been preserved since the end of the first run of Saturn V rockets two years before.
Despite the unexpectedly strong challenge from North American, Boeing’s design for the Space Lifter was similar in broad strokes to their previous designs for reusable S-ICs, ranging back to the earliest 1962 Marshall studies: a broad delta wing grafted to the side of a fuselage derived from the existing 10-meter S-IC tanks, with a cockpit and nose in the front and a set of airbreathing engines below the wing around the middle, near the intertank between the kerosene and liquid oxygen tanks. However, the design now needed to address aspects which had been left as “details for later study” in its earlier ancestors. Would the landing engines use feed lines to a new side-located sump in the kerosene tank, or were smaller “ferry” tanks just for flyback prefered to minimize the risk of slosh within nearly-dry fuel tanks? How would the VAB, Michoud, and other facilities be able to handle the large rudders necessary for the aerodynamic control of the booster? A variant of the F-101 engine was selected for the airbreathing propulsion system, but the manufacturer, General Electric, would have to do additional tests on how the engines would be started during a supersonic glide as the booster exited the hypersonic portions of its return to Earth. Although Rocketdyne had already designed the F-1 engine for up to 20 starts and an operating time of up to 2250 seconds between major overhauls, part of requirements to enable the initial proving tests back in the late 50s, the Lifter would require two starts on its engines in every mission: once at liftoff, the other above the atmosphere to slow the vehicle for entry. This air start had to be completely reliable--without it, the vehicle’s structure would be incapable of surviving entry in a condition to be reused. A new variant, the F-1B, was commissioned from Rocketdyne to enable this use.
The design of the crew cabin and nose posed additional challenges. The Space Lifter design called for the assured ability to get the Lifter’s flight crew away from the stack in the event of any abort before separation. Thus, the vehicle needed not just a cockpit, but an entire ejectable flight deck--a separate spacecraft capable of independently surviving atmospheric entry at an un-slowed speed, then ditching in the ocean and staying afloat while rescue crews arrived at the site. With most of Boeing’s efforts focused on the broader vehicle, the company decided to subcontract the design of the abort capsule, and thus of the flight deck of the vehicle. In 1973, Boeing gave the contract to the same Grumman team they had worked with during the initial Phase B Shuttle studies, then opposed in the TAOS/ISRS configuration debate just a year later. Friends and enemies changed quickly in the military-industrial complex, and Grumman’s work on their entry for the glider competition gave useful grounds for the work on the design of the abort capsule and flight deck. Below the flight deck and forward of the liquid oxygen tank was another major feature which would go on to inspire serious concerns: the vehicle’s nose structure. Boeing’s original concepts called for the “point” of the booster’s nose to slide backwards prior to integration, creating a space for the upper stage engine to be stored prior to separation. This would enable the upper stage to mount directly to the forward structure of the booster and eliminate a need for a disposable interstage fairing. For return flight, the nose would extend and lock, covering the gap for atmospheric entry. At the time, it was anticipated to be complex, but not more of a problem than any other part of the RS-IC.
With the specifics of the booster laid out, Marshall focused on fleshing out the other portion of the Space Lifter design: the expendable stage which would complete the ascent to orbit and deliver the payload, whether that be Shuttle or a satellite. The design of the upper stage was bounded by the capabilities of the booster, but the responses received following the June 1972 Request for Proposal included a variety of specific approaches. The final selection converged on two top designs. The first, from McDonnell-Douglas, was a stretched “Chinese copy” of their S-IVB stage: a lengthened stage incorporating many changes to enable higher-rate production at lower cost. Building on their own work during Saturn cost reduction studies, McDonnell estimated that they could produce the stages for roughly half the cost of their S-IVB while drawing extensively on the existing production, handling, and checkout facilities created for Apollo. The design also called for a slight modification to the J-2S engines developed for the S-IVB, giving them a nozzle with an 84:1 area ratio rather than the stock 40:1, to increase vacuum specific impulse from 436 seconds to 451, the Isp targeted by the Space Shuttle Main Engine. The second, from Convair, was a an oversized “balloon tank” design, similar to the design of their Centaur upper stage though scaled up dramatically in every dimension. The result would be a fantastically high-performance stage, particularly if fitting with a cluster of up to ten RL-10s instead of the lower-performing (without the nozzle extension) J-2S. The Convair proposal was scored highly on their grasp on technical issues and their studies of low-cost production: the study included many pages detailing how their stage could be built using cheap rolling techniques, the low costs Pratt & Whitney was willing to project for the required numbers of RL-10s, and drawing on their Atlas missile experience to explain how production of 70 or more stages per year could be economically supported. In the end, the deciding factor was initial design cost, as it had been with Marshall’s selection of the RS-IC.
As the year had worn on, it had become apparent that Johnson was running behind and that the design of the glider might prove more expensive than had been projected originally. If any Shuttle was to actually carry astronauts to space, Marshall would have to economize its development to cover Johnson’s overruns--even if this meant elevated recurring costs in the future. Among much grumbling from Marshall’s management, who resented being handicapped in their work to assist another center which was unable to manage its area of responsibility, cost was ranked higher in the selection criteria, and McDonnell’s S-IVC lept to the top of the list. With Marshall’s existing relationship with McDonnell on the S-IVB, it wasn’t an undesirable result, but Johnson’s overruns remained a point of contention between Marshall and Johnson as the program developed.
The Space Lifter upper stage wasn’t the only project to suffer as the decisions on the design of the glider dragged on and questions about budget were raised, and the consequences to other programs were more permanent. Only a few years before in 1969, the nuclear thermal engine NERVA had beckoned to open up the planets, while Pratt and Rocketdyne had competed for the prize of the high-pressure, high-thrust, long-life Space Shuttle Main Engine--a staged-combustion hydrogen-oxygen engine with a chamber pressure three times that of the modern F-1B. This SSME was to have been used on both stages of the early and fully reusable Space Shuttle designs. With the selection of Boeing’s RS-IC booster over North American Rockwell’s RS-II and the use of the expendable J-2S-2 on McDonnell’s S-IVC upper stage, the SSME was a very expensive project without a purpose, just like NERVA had become. Both of NASA’s new high-technology engines were targeted for elimination, in spite of protests from engineers involved and congressional representatives from the districts affected. Rocketdyne was partially compensated for the cancellation of SSME with their contract for the F-1B, but many planners felt as though the quest of NASA for ever-more-advanced technology had ended: the engines for the Space Lifter would be bound firmly within the 50s-era past, not the advances of the future.
The issues with the budget may have been encountered primarily by the Manned Space Flight Center and their work on the glider, but the root of the issue came directly from the original Shuttle Decision and announcement. While the ISRS program had already studied many details on the specific booster and upper stage requirements, meaning Marshall was working towards a very well-defined vehicle, the glider had emerged from the Flax Committee recommendations barely more than some rough conceptual numbers on a blank sheet of paper: a 45,000 pound dry-weight vehicle with capacity for six to eight crew and up to 10,000 pound payload in a 10 foot by 20 foot payload bay. It was a rough enough set of specifications that every major group within NASA could project their preferred designs for the Shuttle onto them, and the result was that the process of preparing the Request for Proposal for the orbiter design was lively at best, and completely chaotic at worst. Maxime Faget once again raised the question if cross-range was still a critical requirement, and thus if his preferred (and patented) straight wings could be used instead of the delta wings which had emerged as the preferred option for both the booster and the TAOS orbiters. The glider design group also reexamined the choice of tiles versus hot structures for the glider's thermal protection. With such core questions reopened, configuration questions and studies abounded. The Manned Space Flight Center was quickly swamped with alternative designs as they worked to focus on a single design for the final Request for Proposal as groups took a last opportunity to pitch the advantages of their designs. The most emblematic of this came with a final attempt by McDonnell to pitch a variant of their Big Gemini: if the glider only needed to reach orbit and return, why couldn't a capsule with internal payload bay serve just as well?
It took almost six months to once again review and retire these resurgent, previously abandoned designs. The Shuttle still needed to have cross range for polar orbit and for a greater number of landing opportunities, which straight wings like Faget’s orbiter couldn’t achieve. However, there were concerns about the high peak heating which might be experienced on the leading edges of a delta-winged orbiter headed to space, and on the volumetric efficiency of such a design for the smaller glider. Advocates of the delta wing and straight wing orbiter reached loggerheads, which left an opening for a compromise neither liked. Lifting bodies, with small aerodynamic surfaces providing control for a vehicle whose fuselage provided most of the lift, had been extensively studied by NASA and the USAF at Edwards Air Force Base. These early tests of the X-24 demonstrated the advantages of such a design for a small but maneuverable entry vehicle. Several of the studied designs could achieve the cross range required by the Air Force for single-orbit polar missions, but the blunter bodies offered more volume and lower overall heating than the thin leading edges of a delta wing. The debate went in circles for weeks, then months, and the delays lead Administrator Fletcher and others familiar with OMB and Congress to worry that if Shuttle didn't get moving, it might put the entire Space Transportation System in jeopardy. The pressure came down on high in a series of meetings with the design leadership. In one legendary (and possibly apocryphal) story, a NASA manager began one of these meetings by upending a briefcase full of various contractor models onto the conference table, sending lifting bodies, delta-wings, straight-wings, and capsules scattering across the tabletop. “Do we want to keep building these? Because if we do, we’re not getting the money for the real one,” he supposedly continued. Whether the incident is true or not, the message from Fletcher on down was clear: if NASA was going to have an orbiter at all, they needed to get moving. The final design settled on the lifting body, offering a design with the volume for a larger crew cabin and payload bay, and the cross-range required for USAF missions. Orbital maneuvering propellant and other systems could be packed into oddly-shaped spaces within the structure which wouldn’t have fit the propellant tanks of an orbiter with its own propulsion. A grudging agreement was secured on these points, and the lifting body emerged as the selected architecture.
Even after the Lifting Body architecture was settled upon, debate raged about the exact capabilities of the eventual Orbiter, most particularly with regard to its propulsion systems. The Orbiter initially called for two jet engines, to be used in the last phase of flight for assistance in landing and giving the crew the ability to go around for another pass if the first approach did not seem feasible. Deke Slayton, at the Astronaut Office, insisted on these engines for a long time, despite protests from lifting body test pilots from Edwards AFB that they were totally unnecessary, as demonstrated by hundreds of unpowered landings at that base. Slayton countered that, after an extended time in orbit, the astronauts would be out-of-practice at actual piloting, unlike the Edwards pilots, who trained in the simulator up to the day of their actual flights. Even after the RFP was published, the debate raged, and not until late 1972 did the requirement for jet propulsion disappear, as the impact on Orbiter payload (a full 25% reduction from 8 tons to 6) ultimately trumped Slayton’s caution.
Further debate centered on the Launch Abort System. In a break from Apollo and building on the precedent of Gemini, the Orbiter was to be equipped only with ejection seats, and these only for the first few missions. The system was to be built safe enough that an abort tower would be unnecessary. This decision was criticized from numerous corners, particularly from the astronaut office, but statistical analysis indicated that an abort tower would only be useful in a handful of abort scenarios anyway. This did not stop Thiokol and other solid rocket motor manufacturing companies from lobbying to reverse the decision in any way possible--up to and including going over Administrator Fletcher’s head to the President of the Church of Jesus Christ of Latter-Day Saints, who met his coreligionist and tried to persuade him to direct some work to Utah. Somewhat angrily, Fletcher responded that any decision he made would be in the interests of the US government and NASA first, and Thiokol last.
Ultimately, engineers at Martin-Marietta hit on a compromise that allowed abort capability without unduly driving up per-mission costs or reducing Orbiter payload too badly. In order to accomplish all the missions intended for it, the Orbiter had to be able to maneuver in orbit, to the tune of at least 300 m/s of delta-v. This required a storable propellant engine and sizeable propellant tanks. Drawing on their experience with the Titan II upper stage, which NASA had trusted to lift Gemini crews to orbit without redundancy, they proposed an Integrated Launch Abort and Maneuvering System, using the same propellant for orbital adjustments and for launch abort, as no mission could conceivably involve both operations. In November 1973, NASA adjusted the requirements for the Orbiter to feature just such a system, with one AJ-10 for orbital maneuvering and four of the Titan-legacy LR-91 engines for abort thrust, tackling the problems of maneuvering and abort with the same system. With the Shuttle configuration finally largely decided, Houston was able to push a Request for Proposal out the door just before the close of 1972.
North American Rockwell, who had so far been unable to secure any work on the Space Lifter, devoted substantial effort to their Shuttle proposal, and their experience with the X-15, Valkyrie, and Apollo programs served them well in preparing one of the top two responses. For additional experience in the design of lifting body vehicles, NAR partnered in their proposal with Martin, who brought extensive experience with the type, and which had won support in NASA by proposing the ILAMS system. The strongest competition in technical scoring came from Grumman, who joined with Northrop on the design of their Shuttle. However, while Grumman's design was ranked well in technical aspects, including the lowest dry weight of any entrant, its proposed system designs were criticized as excessively complex and there were concerns expressed about the company's shaky financial footing. It certainly did not help Grumman’s case that Willard Rockwell and other members of the North American and Rockwell leaderships had been donors to the Republican Party in general and President Nixon in particular since the 1950s. Whether or not corruption was involved, the result was that in March 1973, the NAR proposal was officially selected. However, Grumman was able to secure a major consolation prize: Boeing accepted a proposal from them for the subcontract on the Space Lifter's cockpit abort pod.
The Orbiter, as finally proposed by North American and Martin, was based on an enlarged Martin X-24A lifting body, whose blunt nose was deemed less vulnerable to heating at hypersonic speeds than the pointed nose of the X-24B, with facilities for six crew (though, in practice, it was not supposed to fly with that many occupants except for very short space station crew rotation flights). The use of conduction- and liquid-coolant-based heat rejection made it possible to operate the spacecraft at an internal pressure of either 14.7 oxygen-nitrogen or 5 psi pure oxygen, depending on mission requirements. The payload bay was wedged in front of the vertical stabilizer, 10 feet by 20 feet, just big enough for small satellites or other test payloads. A small airlock and docking system, based on the Docking Module in development for the Apollo-Soyuz Test Project, was designed to mount at the forward end of the bay, tied into the cabin for missions which would require docking or EVA.
With the prime contractors for the Space Lifter, its upper stage, and the Space Shuttle orbiter decided, 1973 found a veritable army of engineers setting to work on the components of the Space Transportation System. Marshall had already been serving as the hub of feverish work surrounding the RS-IC booster and the S-IVC upper stage; now the newly-renamed Johnson Space Center became the center of their own new web of contractors and subcontractors as North American Rockwell dug into the task of turning their Space Shuttle design into a flying vehicle within five years.
With the design of the vehicle taking shape, studies also began at Kennedy Space Center on how the vehicles would be handled, assembled, and launched. Some study was given to launching the Space Transportation System from other sites, ranging up and down the eastern seaboard and the west coast in search of cheap and functional sites for equatorial and polar launches. Senator Clinton Anderson from New Mexico repeatedly attempted to influence a decision in favor of a new joint polar and equatorial launch site located at White Sands: flights of the Lifter downrange to the east for equatorial flights and to the north for polar flights would overfly one of his state's most plentiful resources: underpopulated land. Thus, some studies suggested, it would be easier to land the Space Lifter down range with less fuel for the Lifter's air-breathing jets. After landing down range, the Lifter could refuel and and work its way back to the launch site via a series of commercial and Strategic Air Command airstrips. However, while alternate launch sites received extensive lobbying focus, they were quickly revealed as the fantasies they were, given the substantial infrastructure that existing sites already possessed. In particular, given the significant heritage that the Space Lifter would share with the Saturn V and existing infrastructure at KSC, the Cape was rapidly confirmed as the site for equatorial launches. Vandenberg Air Force Base in California was selected as the polar launch site, with the Space Lifter to join the rockets it might someday replace.
With the inevitable confirmed, work began on laying out changes which would be required to the Mobile Launch Platforms, Mobile Servicing Tower, Vehicle Assembly Building, and other infrastructure around Cape Canaveral. As Boeing's plans for the Lifter firmed up in 1974, ground was broken on a set of large hangars and servicing facilities for the new boosters, while across the road another survey party took measurements to lay out the location of a smaller set for the maintenance of the Orbiters. Kennedy was still planned to see the launch of one final Saturn IB and Apollo for the Apollo-Soyuz Test Project, but NASA's most famous launch site--along with the rest of the agency--was already actively working towards their next challenge. The politics and contracts were complete and the teams had been assembled. However, the challenge of getting from a designs on paper to a vehicle on the pad still remained to be met.
Chapter 3: Assembly
With the arrival of the Constitution in the Vehicle Assembly Building to join the already-present S-IVC stage and the Space Shuttle Endeavour, the pieces were in place for the first operational Space Shuttle mission. The only task remaining was to fit them into their proper places in the stack, integrating them into a single assembly to prepare them for flight. It was a familiar task for the VAB technicians, and they set to work with their typical care and skill. This particular stack drew particular interest from visiting tourists and NASA engineers alike, but the attention was nothing new to the team which had less than a decade before prepared Saturn V moon rockets in these very same spaces. Now, descendants of those famous craft were being readied for a mission much closer to home--but no less important for the future of NASA's space exploration ambitions.
The assembly process began with the arrival of Crawler-Transporter 1, bearing on its back Mobile Launch Platform 3, which had been the first of the three MLPs to have its Launch Umbilical Tower modified to service the RS-IC Space Lifter. Under the eyes of a dozen directing technicians, the driver in the cab positioned the massive steel structure within High Bay 3, then gently lowered it onto the waiting support mounts. Technicians swarmed over the MLP, conducting the final checks of the hold-down mounts and service masts in preparation for the stacking process. Meanwhile, other technicians in High Bay 4, located across the transfer aisle on the west side of the building, worked around Constitution, still resting on her transport trailer beneath the five hundred foot ceiling. Not for much longer--the crews used the massive travelling cranes up in the rafters to position and mount two large yellow lifting fixtures to the nearly-747-sized vehicle. One mounted near the nose, just aft of the cockpit, supported by the new 325-ton crane added specifically for working with the RS-IC's bulk. The other, closer to the engines, was supported by the original Apollo-era 250-ton crane running on the same tracks. Technicians with torque wrenches worked their way around the lift fixtures, cross-checking the inch-thick mounting bolts for the fixtures. With that complete, the crews stepped back towards the walls, and while tourists looked on from the roped-off area in the transfer aisle, the overhead cranes took up the slack. Like a massive Harrier, the delta-winged booster lifted straight up off the transport rig--first a foot, then two, then ten, then thirty. With enough height, the two overhead crane operators almost 500 feet above worked a careful ballet at the direction of headset-wearing technicians on the ground. The 325 ton crane pulled in its lines, raising the RS-IC's nose as the 250-ton crane closed the distance between them, bringing the tail into line under the nose. Like a marionette on strings, the massive vehicle pirouetted and pointed its nose skywards, its wing-mounted tails clearing the floor by less than ten feet as its nose rose almost 200 feet into the air.
With the vehicle lifted to the vertical, the two overhead cranes worked together, lifting the booster up by its own length, clearing the cross-bracing of the VAB structure at the 160 foot level and twisting it slightly around its axis to clear its wings through the gap into the transfer aisle. Engineers watched with technicians and yet more tourists as the booster--the size of the Statue of Liberty--crossed overhead beneath the two cranes, moving directly across the transfer aisle and into the the waiting High Bay 3, supported only by the thick cables--made thin by distance. More than a few let out careful breaths as the booster was lowered back to the level of the MLP deck, carefully aligned by technicians, then finally lowered onto the launch hold-down mounts and secured. The tension abated almost palpably as the MLP took up the weight. With the move done, the cranes and their fixtures were detached and work platforms were lowered into place around the booster. The cranes went to work on the next tasks, moving the far lighter S-IVC stage into the transfer aisle, lifting it to vertical, and handing it off to the large overhead crane. With the aft skirt and interstage which would protect its engine already attached, the S-IVC was lowered onto the mounting points on the nose of the RS-IC. As yet more work platforms were swung out to access the S-IVC, the cranes went back for the final pieces: the 30-ton Space Shuttle and its adapter. Once lifted into position, the Shuttle crowned a stack that was almost 300 feet tall. The final set of work platforms were rotated into place to access the Shuttle, and the engineers and technicians of the VAB crew set to work finishing the job of checking out the integrated vehicle. Four days after the arrival of Constitution in the VAB, the stack was assembled. Now it needed to be tested and readied for flight.
With Presidential support secured for the Space Transportation System, NASA was able to line up several key trump cards behind the program, beginning in the oval office, moving down to supporters like Cap Weinberger at the Office of Management and Budget, and powerful Congressional interests from districts representing aerospace-heavy areas like California, Florida, Alabama, and Texas. It could also offer a vision for the future of space exploration directly endorsed by the President himself to follow the highwater marks of Apollo: a future where spaceflight might not be limited to the select group of military test pilots who in 1972 had so far landed on the moon, but scientists, doctors, blue-collar workers on space construction projects, teachers, reporters, and housewives. The vision of accomplishing missions in space in a cheaper, more cost effective way was a vision that was embraced to some extent by both space enthusiasts and space skeptics alike--though many of the latter still doubted if the savings of the vehicles depicted on paper could be achieved by vehicles built of metal. However, to see these plans tested, NASA would first have to move forward with translating these political successes into the reality of a new generation of manned spacecraft. The assembly of NASA’s centers and contractors behind the project and the division of responsibility for the vehicle began shortly after the President’s approval of the program.
The distinction between the parts of the Space Transportation System offered a natural break between the spheres of influence of the agency’s most powerful centers: the Space Lifter was the obvious province of Marshall Spaceflight Center in Huntsville, while the Space Shuttle glider became with little challenge the preserve of the Manned Space Flight Center in Houston. As with Apollo, Marshall would provide the rocket, while Houston would supply the vehicle, crew, and carry out the missions. This wasn’t the only connection to Apollo, however. It was assumed within many of the studies supporting the ISRS architecture that the booster would be derived from existing stages and tooling, and the result was a rapid--and largely pro forma--Request for Proposal being issued February 21, 1972 with all proposals due two months later on April 21. Boeing, the foremost industry advocate for ISRS and originator of many of the key concepts with their involvement in the INT-22 design studies of similar vehicles in the mid-60s, unsurprisingly submitted one of the strongest proposals for the Space Lifter booster. However, a surprisingly strong second submission came from North American Rockwell, who proposed to draw on their history with the X-15 (described in their proposal as the “first reusable suborbital rocketplane”) and the XB-70 Valkyrie Mach 3 bomber in the development of a Space Lifter derived not from the Saturn V first stage, but from its second stage, using the same ballasted, retro-boosting hot structure approach applied to the S-II stage that Boeing suggested to apply to the S-IC. However, NAR’s proposal was weaker in several areas, particularly development cost: the J-2 engines of the S-II would need to be replaced with new high-pressure engines like the proposed SSME, the VAB and MLPs would need to be more heavily modified to mount to the S-II at zero level, and other changes would cascade through the architecture. Thus, though North American’s proposal was rated quite highly, the contract was awarded in May to Boeing. Marshall and Boeing immediately set to work fleshing out the details of the design and arranging the evaluation of S-IC tooling which had been preserved since the end of the first run of Saturn V rockets two years before.
Despite the unexpectedly strong challenge from North American, Boeing’s design for the Space Lifter was similar in broad strokes to their previous designs for reusable S-ICs, ranging back to the earliest 1962 Marshall studies: a broad delta wing grafted to the side of a fuselage derived from the existing 10-meter S-IC tanks, with a cockpit and nose in the front and a set of airbreathing engines below the wing around the middle, near the intertank between the kerosene and liquid oxygen tanks. However, the design now needed to address aspects which had been left as “details for later study” in its earlier ancestors. Would the landing engines use feed lines to a new side-located sump in the kerosene tank, or were smaller “ferry” tanks just for flyback prefered to minimize the risk of slosh within nearly-dry fuel tanks? How would the VAB, Michoud, and other facilities be able to handle the large rudders necessary for the aerodynamic control of the booster? A variant of the F-101 engine was selected for the airbreathing propulsion system, but the manufacturer, General Electric, would have to do additional tests on how the engines would be started during a supersonic glide as the booster exited the hypersonic portions of its return to Earth. Although Rocketdyne had already designed the F-1 engine for up to 20 starts and an operating time of up to 2250 seconds between major overhauls, part of requirements to enable the initial proving tests back in the late 50s, the Lifter would require two starts on its engines in every mission: once at liftoff, the other above the atmosphere to slow the vehicle for entry. This air start had to be completely reliable--without it, the vehicle’s structure would be incapable of surviving entry in a condition to be reused. A new variant, the F-1B, was commissioned from Rocketdyne to enable this use.
The design of the crew cabin and nose posed additional challenges. The Space Lifter design called for the assured ability to get the Lifter’s flight crew away from the stack in the event of any abort before separation. Thus, the vehicle needed not just a cockpit, but an entire ejectable flight deck--a separate spacecraft capable of independently surviving atmospheric entry at an un-slowed speed, then ditching in the ocean and staying afloat while rescue crews arrived at the site. With most of Boeing’s efforts focused on the broader vehicle, the company decided to subcontract the design of the abort capsule, and thus of the flight deck of the vehicle. In 1973, Boeing gave the contract to the same Grumman team they had worked with during the initial Phase B Shuttle studies, then opposed in the TAOS/ISRS configuration debate just a year later. Friends and enemies changed quickly in the military-industrial complex, and Grumman’s work on their entry for the glider competition gave useful grounds for the work on the design of the abort capsule and flight deck. Below the flight deck and forward of the liquid oxygen tank was another major feature which would go on to inspire serious concerns: the vehicle’s nose structure. Boeing’s original concepts called for the “point” of the booster’s nose to slide backwards prior to integration, creating a space for the upper stage engine to be stored prior to separation. This would enable the upper stage to mount directly to the forward structure of the booster and eliminate a need for a disposable interstage fairing. For return flight, the nose would extend and lock, covering the gap for atmospheric entry. At the time, it was anticipated to be complex, but not more of a problem than any other part of the RS-IC.
With the specifics of the booster laid out, Marshall focused on fleshing out the other portion of the Space Lifter design: the expendable stage which would complete the ascent to orbit and deliver the payload, whether that be Shuttle or a satellite. The design of the upper stage was bounded by the capabilities of the booster, but the responses received following the June 1972 Request for Proposal included a variety of specific approaches. The final selection converged on two top designs. The first, from McDonnell-Douglas, was a stretched “Chinese copy” of their S-IVB stage: a lengthened stage incorporating many changes to enable higher-rate production at lower cost. Building on their own work during Saturn cost reduction studies, McDonnell estimated that they could produce the stages for roughly half the cost of their S-IVB while drawing extensively on the existing production, handling, and checkout facilities created for Apollo. The design also called for a slight modification to the J-2S engines developed for the S-IVB, giving them a nozzle with an 84:1 area ratio rather than the stock 40:1, to increase vacuum specific impulse from 436 seconds to 451, the Isp targeted by the Space Shuttle Main Engine. The second, from Convair, was a an oversized “balloon tank” design, similar to the design of their Centaur upper stage though scaled up dramatically in every dimension. The result would be a fantastically high-performance stage, particularly if fitting with a cluster of up to ten RL-10s instead of the lower-performing (without the nozzle extension) J-2S. The Convair proposal was scored highly on their grasp on technical issues and their studies of low-cost production: the study included many pages detailing how their stage could be built using cheap rolling techniques, the low costs Pratt & Whitney was willing to project for the required numbers of RL-10s, and drawing on their Atlas missile experience to explain how production of 70 or more stages per year could be economically supported. In the end, the deciding factor was initial design cost, as it had been with Marshall’s selection of the RS-IC.
As the year had worn on, it had become apparent that Johnson was running behind and that the design of the glider might prove more expensive than had been projected originally. If any Shuttle was to actually carry astronauts to space, Marshall would have to economize its development to cover Johnson’s overruns--even if this meant elevated recurring costs in the future. Among much grumbling from Marshall’s management, who resented being handicapped in their work to assist another center which was unable to manage its area of responsibility, cost was ranked higher in the selection criteria, and McDonnell’s S-IVC lept to the top of the list. With Marshall’s existing relationship with McDonnell on the S-IVB, it wasn’t an undesirable result, but Johnson’s overruns remained a point of contention between Marshall and Johnson as the program developed.
The Space Lifter upper stage wasn’t the only project to suffer as the decisions on the design of the glider dragged on and questions about budget were raised, and the consequences to other programs were more permanent. Only a few years before in 1969, the nuclear thermal engine NERVA had beckoned to open up the planets, while Pratt and Rocketdyne had competed for the prize of the high-pressure, high-thrust, long-life Space Shuttle Main Engine--a staged-combustion hydrogen-oxygen engine with a chamber pressure three times that of the modern F-1B. This SSME was to have been used on both stages of the early and fully reusable Space Shuttle designs. With the selection of Boeing’s RS-IC booster over North American Rockwell’s RS-II and the use of the expendable J-2S-2 on McDonnell’s S-IVC upper stage, the SSME was a very expensive project without a purpose, just like NERVA had become. Both of NASA’s new high-technology engines were targeted for elimination, in spite of protests from engineers involved and congressional representatives from the districts affected. Rocketdyne was partially compensated for the cancellation of SSME with their contract for the F-1B, but many planners felt as though the quest of NASA for ever-more-advanced technology had ended: the engines for the Space Lifter would be bound firmly within the 50s-era past, not the advances of the future.
The issues with the budget may have been encountered primarily by the Manned Space Flight Center and their work on the glider, but the root of the issue came directly from the original Shuttle Decision and announcement. While the ISRS program had already studied many details on the specific booster and upper stage requirements, meaning Marshall was working towards a very well-defined vehicle, the glider had emerged from the Flax Committee recommendations barely more than some rough conceptual numbers on a blank sheet of paper: a 45,000 pound dry-weight vehicle with capacity for six to eight crew and up to 10,000 pound payload in a 10 foot by 20 foot payload bay. It was a rough enough set of specifications that every major group within NASA could project their preferred designs for the Shuttle onto them, and the result was that the process of preparing the Request for Proposal for the orbiter design was lively at best, and completely chaotic at worst. Maxime Faget once again raised the question if cross-range was still a critical requirement, and thus if his preferred (and patented) straight wings could be used instead of the delta wings which had emerged as the preferred option for both the booster and the TAOS orbiters. The glider design group also reexamined the choice of tiles versus hot structures for the glider's thermal protection. With such core questions reopened, configuration questions and studies abounded. The Manned Space Flight Center was quickly swamped with alternative designs as they worked to focus on a single design for the final Request for Proposal as groups took a last opportunity to pitch the advantages of their designs. The most emblematic of this came with a final attempt by McDonnell to pitch a variant of their Big Gemini: if the glider only needed to reach orbit and return, why couldn't a capsule with internal payload bay serve just as well?
It took almost six months to once again review and retire these resurgent, previously abandoned designs. The Shuttle still needed to have cross range for polar orbit and for a greater number of landing opportunities, which straight wings like Faget’s orbiter couldn’t achieve. However, there were concerns about the high peak heating which might be experienced on the leading edges of a delta-winged orbiter headed to space, and on the volumetric efficiency of such a design for the smaller glider. Advocates of the delta wing and straight wing orbiter reached loggerheads, which left an opening for a compromise neither liked. Lifting bodies, with small aerodynamic surfaces providing control for a vehicle whose fuselage provided most of the lift, had been extensively studied by NASA and the USAF at Edwards Air Force Base. These early tests of the X-24 demonstrated the advantages of such a design for a small but maneuverable entry vehicle. Several of the studied designs could achieve the cross range required by the Air Force for single-orbit polar missions, but the blunter bodies offered more volume and lower overall heating than the thin leading edges of a delta wing. The debate went in circles for weeks, then months, and the delays lead Administrator Fletcher and others familiar with OMB and Congress to worry that if Shuttle didn't get moving, it might put the entire Space Transportation System in jeopardy. The pressure came down on high in a series of meetings with the design leadership. In one legendary (and possibly apocryphal) story, a NASA manager began one of these meetings by upending a briefcase full of various contractor models onto the conference table, sending lifting bodies, delta-wings, straight-wings, and capsules scattering across the tabletop. “Do we want to keep building these? Because if we do, we’re not getting the money for the real one,” he supposedly continued. Whether the incident is true or not, the message from Fletcher on down was clear: if NASA was going to have an orbiter at all, they needed to get moving. The final design settled on the lifting body, offering a design with the volume for a larger crew cabin and payload bay, and the cross-range required for USAF missions. Orbital maneuvering propellant and other systems could be packed into oddly-shaped spaces within the structure which wouldn’t have fit the propellant tanks of an orbiter with its own propulsion. A grudging agreement was secured on these points, and the lifting body emerged as the selected architecture.
Even after the Lifting Body architecture was settled upon, debate raged about the exact capabilities of the eventual Orbiter, most particularly with regard to its propulsion systems. The Orbiter initially called for two jet engines, to be used in the last phase of flight for assistance in landing and giving the crew the ability to go around for another pass if the first approach did not seem feasible. Deke Slayton, at the Astronaut Office, insisted on these engines for a long time, despite protests from lifting body test pilots from Edwards AFB that they were totally unnecessary, as demonstrated by hundreds of unpowered landings at that base. Slayton countered that, after an extended time in orbit, the astronauts would be out-of-practice at actual piloting, unlike the Edwards pilots, who trained in the simulator up to the day of their actual flights. Even after the RFP was published, the debate raged, and not until late 1972 did the requirement for jet propulsion disappear, as the impact on Orbiter payload (a full 25% reduction from 8 tons to 6) ultimately trumped Slayton’s caution.
Further debate centered on the Launch Abort System. In a break from Apollo and building on the precedent of Gemini, the Orbiter was to be equipped only with ejection seats, and these only for the first few missions. The system was to be built safe enough that an abort tower would be unnecessary. This decision was criticized from numerous corners, particularly from the astronaut office, but statistical analysis indicated that an abort tower would only be useful in a handful of abort scenarios anyway. This did not stop Thiokol and other solid rocket motor manufacturing companies from lobbying to reverse the decision in any way possible--up to and including going over Administrator Fletcher’s head to the President of the Church of Jesus Christ of Latter-Day Saints, who met his coreligionist and tried to persuade him to direct some work to Utah. Somewhat angrily, Fletcher responded that any decision he made would be in the interests of the US government and NASA first, and Thiokol last.
Ultimately, engineers at Martin-Marietta hit on a compromise that allowed abort capability without unduly driving up per-mission costs or reducing Orbiter payload too badly. In order to accomplish all the missions intended for it, the Orbiter had to be able to maneuver in orbit, to the tune of at least 300 m/s of delta-v. This required a storable propellant engine and sizeable propellant tanks. Drawing on their experience with the Titan II upper stage, which NASA had trusted to lift Gemini crews to orbit without redundancy, they proposed an Integrated Launch Abort and Maneuvering System, using the same propellant for orbital adjustments and for launch abort, as no mission could conceivably involve both operations. In November 1973, NASA adjusted the requirements for the Orbiter to feature just such a system, with one AJ-10 for orbital maneuvering and four of the Titan-legacy LR-91 engines for abort thrust, tackling the problems of maneuvering and abort with the same system. With the Shuttle configuration finally largely decided, Houston was able to push a Request for Proposal out the door just before the close of 1972.
North American Rockwell, who had so far been unable to secure any work on the Space Lifter, devoted substantial effort to their Shuttle proposal, and their experience with the X-15, Valkyrie, and Apollo programs served them well in preparing one of the top two responses. For additional experience in the design of lifting body vehicles, NAR partnered in their proposal with Martin, who brought extensive experience with the type, and which had won support in NASA by proposing the ILAMS system. The strongest competition in technical scoring came from Grumman, who joined with Northrop on the design of their Shuttle. However, while Grumman's design was ranked well in technical aspects, including the lowest dry weight of any entrant, its proposed system designs were criticized as excessively complex and there were concerns expressed about the company's shaky financial footing. It certainly did not help Grumman’s case that Willard Rockwell and other members of the North American and Rockwell leaderships had been donors to the Republican Party in general and President Nixon in particular since the 1950s. Whether or not corruption was involved, the result was that in March 1973, the NAR proposal was officially selected. However, Grumman was able to secure a major consolation prize: Boeing accepted a proposal from them for the subcontract on the Space Lifter's cockpit abort pod.
The Orbiter, as finally proposed by North American and Martin, was based on an enlarged Martin X-24A lifting body, whose blunt nose was deemed less vulnerable to heating at hypersonic speeds than the pointed nose of the X-24B, with facilities for six crew (though, in practice, it was not supposed to fly with that many occupants except for very short space station crew rotation flights). The use of conduction- and liquid-coolant-based heat rejection made it possible to operate the spacecraft at an internal pressure of either 14.7 oxygen-nitrogen or 5 psi pure oxygen, depending on mission requirements. The payload bay was wedged in front of the vertical stabilizer, 10 feet by 20 feet, just big enough for small satellites or other test payloads. A small airlock and docking system, based on the Docking Module in development for the Apollo-Soyuz Test Project, was designed to mount at the forward end of the bay, tied into the cabin for missions which would require docking or EVA.
With the prime contractors for the Space Lifter, its upper stage, and the Space Shuttle orbiter decided, 1973 found a veritable army of engineers setting to work on the components of the Space Transportation System. Marshall had already been serving as the hub of feverish work surrounding the RS-IC booster and the S-IVC upper stage; now the newly-renamed Johnson Space Center became the center of their own new web of contractors and subcontractors as North American Rockwell dug into the task of turning their Space Shuttle design into a flying vehicle within five years.
With the design of the vehicle taking shape, studies also began at Kennedy Space Center on how the vehicles would be handled, assembled, and launched. Some study was given to launching the Space Transportation System from other sites, ranging up and down the eastern seaboard and the west coast in search of cheap and functional sites for equatorial and polar launches. Senator Clinton Anderson from New Mexico repeatedly attempted to influence a decision in favor of a new joint polar and equatorial launch site located at White Sands: flights of the Lifter downrange to the east for equatorial flights and to the north for polar flights would overfly one of his state's most plentiful resources: underpopulated land. Thus, some studies suggested, it would be easier to land the Space Lifter down range with less fuel for the Lifter's air-breathing jets. After landing down range, the Lifter could refuel and and work its way back to the launch site via a series of commercial and Strategic Air Command airstrips. However, while alternate launch sites received extensive lobbying focus, they were quickly revealed as the fantasies they were, given the substantial infrastructure that existing sites already possessed. In particular, given the significant heritage that the Space Lifter would share with the Saturn V and existing infrastructure at KSC, the Cape was rapidly confirmed as the site for equatorial launches. Vandenberg Air Force Base in California was selected as the polar launch site, with the Space Lifter to join the rockets it might someday replace.
With the inevitable confirmed, work began on laying out changes which would be required to the Mobile Launch Platforms, Mobile Servicing Tower, Vehicle Assembly Building, and other infrastructure around Cape Canaveral. As Boeing's plans for the Lifter firmed up in 1974, ground was broken on a set of large hangars and servicing facilities for the new boosters, while across the road another survey party took measurements to lay out the location of a smaller set for the maintenance of the Orbiters. Kennedy was still planned to see the launch of one final Saturn IB and Apollo for the Apollo-Soyuz Test Project, but NASA's most famous launch site--along with the rest of the agency--was already actively working towards their next challenge. The politics and contracts were complete and the teams had been assembled. However, the challenge of getting from a designs on paper to a vehicle on the pad still remained to be met.
