On 22 February 1990, Robert L. Crippen, then NASA Space Shuttle Director, issued a memo stating that due to the new “mixed fleet” strategy of using expendable boosters to supplement the Shuttle, the nomenclature “National Space Transportation System” would no longer be used, and the current nomenclature is simply “Space Shuttle Program.” – Dennis Jenkins, Space Shuttle: The History of the National Space Transportation System, The First 100 Missions, 2002, Voyageur Press, Stillwater MN, page v.
Toward the end of the Sixties, during the heady days of Apollo, NASA personnel were eagerly looking ahead to the next program. Many believed that a human mission to Mars should follow Apollo. However, both cost and a lack of relevant technology made this goal a bridge too far (as it still is today). Despite the strong emotional pull of Mars, most engineers understood that a more incremental approach was needed. Fortunately, more than 20 years previously, space guru Wernher von Braun had already outlined this architecture in his book Das Marsprojekt. It was understandable and conceptually quite simple.
The von Braun plan utilized incremental steps. Each step would extend our ability to put people and cargo into space. We would first develop a reusable launch vehicle to get materials into Earth orbit. We then would build a space station in Earth orbit to carry out a variety of scientific and engineering research and serve as a platform to assemble and service the spacecraft needed to go beyond Earth orbit. A “moon tug” or orbital transfer vehicle would be built to get payloads into cislunar space (the space between Earth and Moon). That development would allow us to access the Moon, first to orbit and then to land using a specialized transfer vehicle. With these vehicles, a lunar outpost would be built – a place near the Earth where we would learn to live and work on another world. Finally, an interplanetary vehicle would be built that could send people to Mars.
As each step built the necessary foundation for the next one to follow, this architecture was deemed achievable. The range of access and space capability would increase over time and it allowed an affordable rate of development (no large funding increment was required at the beginning). Why then, if this step-wise plan made so much sense, did America not pursue it? We didn’t because geopolitical considerations trumped technical logic – the call wasn’t for an incremental space faring system but for one that would beat the Soviets by getting an American to the Moon first. In order to do that, von Braun discarded his carefully considered, incremental master plan of permanent space access and replaced it with the Apollo mission plan – an architecture featuring a one-off, mega-booster with a disposable spacecraft.
Following the successful Apollo missions to the Moon, the Space Shuttle was envisioned as the first part in a return to the logical, step-wise von Braun architecture. After the throwaway design of Apollo-Saturn, it was hoped that a reusable Shuttle would be more affordable. In a perfect world, all Shuttle pieces would be reusable, with the main booster returned to the launch site after separating from the smaller orbital stage (which would continue to orbit). Many different designs, developed by various NASA centers and aerospace companies, were considered. A system to get both people and cargo into low Earth orbit would be the first step toward a permanent human program to journey to the planets.
Fiscal realities quickly intruded on the design process. After the massive expenditures needed for the Apollo program, politicians were in the market for an affordable space program. As the Shuttle was (in part) “sold” on that basis, “design to cost” became the ruling principle. This led to a vehicle design that featured partial reusability (with Shuttle orbiter and solid rocket boosters being recovered and reused); only the large external tank would be discarded. Despite this design “compromise,” the basic template – the requirements of the first step of von Braun’s architecture of transporting people and cargo to and from LEO – was fulfilled. In 1972, after some wrangling between Congress and the White House Bureau of Budget, the new program was approved and funded.
The new manned program was named the National Space Transportation System (STS), or Space Shuttle for short. Up until now, manned flight programs had been given poetic, symbolic names, usually taken from mythology. Mercury, Gemini, and Apollo resonated with beauty and symbolism – humankind thundering into the heavens on a historic quest for knowledge and power. This principle was first abandoned when the prosaically named Apollo Applications Program (the follow-on for the Apollo lunar missions that focused on Earth orbital missions using Apollo hardware) was renamed “Skylab.” It was descriptive enough but hardly as inspiring as those derived from the Greco-Roman mythological canon.
Though long and cumbersome, the name “National Space Transportation System” was significant because the utilitarian essence of the von Braun architecture was implicit within it. We were set on a course to establish a permanent space faring infrastructure. The new vehicle would be part of a “transportation system,” not a one-off, space-stunt facilitator. The Space Transportation System would contain all the pieces of von Braun’s plan operated as an end-to-end system. When fully realized, this architecture (shuttle, station, orbital vehicle and interplanetary spacecraft) would maintain program continuity by routinely conducting a wide-variety of missions in LEO and beyond.
The space station was designed and configured as an extension of Shuttle – to serve not only as an orbital laboratory, but also as a staging area for missions beyond. Each piece would be developed incrementally, enabling us to gradually and steadily extended human missions and operations in LEO out to cislunar space, then to the lunar surface and when ready, on to the planets. Thus, the STS designation not only represented the Shuttle as an operational program but also envisioned a future in which we would continuously press and conquer the limits of human presence and influence in space. Shuttle began flying in April of 1981. It conducted scientific experiments, carried satellites into space and began answering our questions of how humans would fare in space. Station was to follow next.
After the Challenger exploded during launch in 1986, the decision was made to develop and use a mixed fleet of space launch vehicles (including the expendables Atlas and Delta, in addition to the Shuttle). This decision made sense from the perspective of one aspect of the Shuttle program, that of it being an all-purpose, reusable launch system. What had been called the Space Transportation System was now dubbed simply the Space Shuttle Program. However, with this seemingly trivial rewriting of the STS program name, the idea of an incremental, cumulative space transportation system (of which Shuttle was only the first piece) was jettisoned. Perhaps a pale remnant of that original idea remained visible as, despite the memo from Bob Crippen quoted above, the “STS” and number designation remained as the official tag of each Shuttle mission. In part, this institutional loss of focus is inevitable in a program of thirty years duration, wherein the people running the Shuttle program in its later phases did not fully understand (or simply forgot) the reasoning behind the program’s original architecture.
Space Station was designed for assembly in stages. Segments were built and constructed with the participation of many countries and one by one, they were launched and transported to LEO on Shuttle flights. Over the course of about 10 years, astronauts assembled the pieces into what is now called the International Space Station (ISS). Wernher Von Braun’s moon tug and interplanetary spacecraft were never realized. It now is 2014. We can clearly see there is no longer a shuttle (except in museums). The space transportation system never made it beyond LEO and we have no plans for the development of one.
Contradicting philosophies of spaceflight are sharply illustrated in this history of space programs. The “Apollo template” envisions missions staged entirely from Earth – launched on massive rockets, carrying everything we need up from the Earth (with various components discarded as they’ve served their purpose), then ending with the return to Earth of a small vehicle carrying its human occupants. In contrast, the “Shuttle template” consists of specialized vehicles, each serving one purpose and creating a gradual, permanent extension into space. Each spacecraft is customized for use in its intended zone and reusable to the extent possible. But these two templates (Apollo and Shuttle) are not mutually exclusive. Parts of an extensible and reusable system can be launched initially using heavy lift vehicles. By following this incremental architecture, a von Braunian space transportation system can be built that will enable dramatic and spectacular space accomplishments. The construction of this system affords vast opportunities and gives us the necessary tools to realize true achievement and a return of value for money spent.
The question before us is: Which transportation paradigm is most likely to develop a permanent and sustainable human presence in space (and all the technology and science that flows from it)? We do know how to build an incremental space transportation system. What we don’t seem able to do is embrace the necessary programmatic structure that facilitates a sustainable and permanent human presence in space.