By the mid 1970s, Low was engaged in a prolonged campaign to limit the center's power and centralize authority in Washington. While this might limit flexibility, he felt preventing the infighting that had just begun to crop up at the end of the '60s as budgets began to fall and ensuring NASA spoke with one voice, as it were, to Congress were far more important goals in the long run. The Strategic Planning Group was an important weapon of his in this goal. As an all-NASA group dedicated to formulating overall development goals and plans, it was of course more beholden to the Administrator than any of the centers. Beyond that, he took measures specifically to make its decisions palatable to the centers, lulling them into dismantling independent planning capability and shunting them into fulfilling only the roles Headquarters desired...
At this time, SPG began to seriously analyze the distant future (at the time, the mid 1980s), and did not like what it found. There had long been a consensus in the group that space stations were the wave of the future. Cheaper than Moon flights, they nevertheless offered an arena in which the United States could successfully engage in manned space flight and demonstrate continuing abilities, besides returning much useful scientific data. However, currently the US relied on Skylab to carry forward that capability, and Skylab was not ideal. It was essentially a heavily modified S-IVB upper stage, and retained many traces of that heritage. It had limited ability to host varying experiments, and was not really designed for the long-endurance, constantly cycling missions that NASA now envisioned for it. Worse, it had a distinctly short lifespan, and was not predicted to be usable much past 1978. NASA possessed a practically identical backup, Skylab B, and a single remaining Saturn V which could hypothetically be used to extend the use of Skylab to about 1983, but after that there were no programs in place, and with the limited funding available it would probably take nearly that long to develop flight-capable hardware.
Accordingly, they recommended to Low that several programs be undertaken:
1. A study of small modular space stations constructed out of a few modules launched by Saturn II or some enhanced derivative. Such a station could be a cheap replacement for Skylab starting the 1980-1983 period, and might be expandable to become a major space platform. Also, the low cost of construction and launch might make it possible to orbit several for different purposes.
2. More advanced varieties of the Apollo spacecraft, in particular the addition of reusability and land landing. Both would help cut costs, the former by reducing the number of capsules NASA would need to procure, the latter by eliminating the costs of a return fleet for each mission. Ensuring adequate land ranges in the US would unfortunately require that missions be launched into less favorable orbits, but it was hoped that the designation of landing sites in Australia--with large tracts of relatively uninhabited land located north of 28 degrees south--would eliminate this issue. Further upgrades considered would be relatively minor enhancements to the capsule's electrical, mechanical, and electronic systems, and more significant ones to its overall capability, such as increasing the number of people the craft could reasonably carry to orbit and back to as many as six, or replacing the probe and drogue docking mechanism with a more flexible "androgynous" mechanism.
3. A study of advanced propulsion systems, particularly enhanced versions of the existing F-1A and J-2S. During the wind-down at the end of the 1960s, and especially after the end of the Shuttle program, development of new or more advanced rocket engines in the United States had practically stopped, except for the solids needed in ICBMs and to boost the military's big expendables. The Soviets, however, had not stopped working on liquid engines, and the SPG felt that the US needed to stay competitive in this field. Besides, larger payloads were needed for future variants of the venerable Apollo spacecraft, or for the proposed small modular space stations, and the cheapest way to do that would be to simply upgrade existing engines for higher performance.
The kernel of all later SPG thinking is present in this report. Absent are major, expensive projects; instead, upgrades to existing capabilities, small forward steps, and extensively proving current capabilities, combined with very in-depth studies of current problems are all key trends which are present in this report. In the poorer climate of the times, and the reluctance of then and later politicians to give large amounts of funding to NASA (witness the practical end of the lunar expedition program after 1990, with only 3 landings resulting), this was an effective policy to maintain and slowly extend NASA's capabilities, never passing beyond what was easily defensible in the budget, but has perhaps been overly conservative in some areas.
As a result of this report, a series of studies were let out over next several years to major aerospace firms to analyze options for future space stations, while the Block III spacecraft was upgraded by 1978 to Block IIIL with a land-landing capability provided by retrorockets firing in the seconds just before touchdown. Curiously, this was quite similar to the Soyuz system, though no evidence has come to light suggesting that either was influenced by the other, especially as the Apollo system was not in service until eleven years after the Soyuz. Certain internal components were redesigned to be at least removable for future use, and an Advanced Propulsion Department was established at Marshall. While all this proved important for later developments, it was all overshadowed by late 1976...
--Touching the Sky: History of Human Space Flight
