The proposals of the final STG report, as delivered to the President in September 1969, were much as depicted in the novel.

The STG proposed a series of common elements: a shuttle, space station modules, a space tug, nuclear shuttles, and a Mars Excursion Module (MEM). The modules could be put together into a series of mission profiles to achieve a variety of goals; only the MEM would have been Mars-specific.

The earliest Mars mission would have left Earth on November 12, 1981, consisting of two nuclear-boosted ships each carrying six men. The expedition would return home on August 14, 1983, and the astronauts brought back to Earth by shuttles.

A series of funding options were presented, ranging from a maximum-pace sprint to Mars by 1982 to a lowest-level funding option which would curtail all manned flight after Apollo. Three central options were presented: Option I aiming for a 1984 Mars landing at a peak cost of $9 billion per year, Option II for 1986 at $8 billion per year, and Option III for no firm landing commitment at $5 billion per year.

The STG proposals were designed to allow incremental near-term decision making, while decisions on more ambitious programs — such as Mars — could be deferred.

It was widely expected that, given the heavy lobbying by NASA and the U.S. aerospace industry, some elements at least of this vision would survive. But public and political reaction was swift and negative.

While it awaited Nixon’s formal response to the STG, further pressure on NASA came in the FY1971 budget process.

Facing further cuts, Paine scrambled to reprioritize. One Skylab and the Apollo-Soyuz Test Project (ASTP) were the sole survivors of the Apollo Applications Program. Apollo 20 was canceled to free up a Saturn V for Skylab. The remaining Apollo missions, 13 through 19, would be stretched out to place two missions after Skylab. There was no prospect of a post-Apollo lunar program. Viking was postponed to 1975.

In January 1970, Nixon somberly told Paine of a Harris poll reporting that 56 percent of Americans believed the costs of Apollo were too great. Nixon said he regretted cuts but could not make an expansive space program a priority. Paine, however, kept up pressure on the President for a greater commitment to NASA’s activities, and this led to hard feelings between them. White House officials concluded that: “We need a new Administrator who will turn down NASA’s empire-building fervor… someone who will work with us rather than against us, and… will shape the program to reflect credit on the President rather than embarrassment.”

In March 1970 Nixon formally endorsed the STG’s third and least expensive option. His language was cautious. “With the entire future and the entire universe before us… we should not try to do everything at once. Our approach to space must continue to be bold — but it must also be balanced.”

Nixon set out six specific objectives: the remaining Apollo missions, Skylab, greater international cooperation in space (essentially ASTP), reducing the cost of space operations (Space Shuttle studies), hastening space technology’s practical application, and unmanned planetary exploration. Nixon made mention of one “major but long range goal we should keep in mind… to eventually send men to explore the planet Mars” (my emphasis). Nixon distanced NASA organizationally from its Apollo past: “We must think of space activities as part of a continuing process… and not as a series of separate leaps, each one requiring a massive concentration of energy and will and accomplished on a crash timetable.”

Essentially, NASA had lost the argument for Mars, and Nixon had (provisionally) chosen the Space Shuttle. In this short but crucial statement, Nixon summarized virtually all of U.S. space policy through the 1970s.

In the Voyage time line, Nixon withdraws this statement before publication; after this crux point, history diverges decisively.

Even after Nixon’s response to the STG, the future of U.S. manned spaceflight was far from assured. To save funds for future programs, on September 2, 1970, Paine cut two more Apollo missions. Paine was out of place in the Nixon administration, and he resigned on September 15.

Congressional critics still wanted more of NASA’s budget trimmed. The familiar partially reusable Shuttle concept emerged in response to the need to halve development costs. But even this did not win automatic approval. In November 1971 the new NASA Administrator, James Fletcher, sent a testy memo to the President arguing that the U.S. could not afford to forgo manned spaceflight altogether, that the shuttle was the only meaningful new program that could be accomplished on a modest budget, and not starting the Shuttle would be highly damaging to the aerospace industry.

But Fletcher did not know that NASA had gained a powerful ally inside the administration in Caspar Weinberger, Deputy Director of the Office of Management and Budget, who wrote to Nixon on August 12, 1971, in support of the Space Shuttle (not of a Mars program!). NASA’s budget was still under threat simply because it was cuttable, Weinberger said. Further NASA cuts would confirm “that our best years are behind us, that we are turning inward, reducing our defense commitments, and voluntarily starting to give up our superpower status and our desire to maintain world superiority.” In a handwritten scrawl on the memo, Nixon added, “I agree with Cap.”

In December 1971 Fletcher learned that Nixon had decided in principle to go ahead with the Shuttle. The decisive factors were the arguments put forward in Weinberger’s and Fletcher’s memos, the fact that so many high-technology programs had already been cut, and — given the decision already to cancel the proposed Supersonic Transport (SST) project — the desire to start some new aerospace program that would avoid unemployment in critical states in the 1972 election year.

On January 5, 1972, Nixon issued a statement announcing the decision to proceed with the development of “an entirely new type of space transportation system designed to help transform the space frontier of the 1970s into familiar territory, easily accessible for human endeavor in the 1980s and ’90s…”

So ended the tortuous post-Apollo decision-making process. In January 1972 Nixon initiated the Shuttle project, not a Mars program.

Mars was lost. But so, nearly, had been the Shuttle — the last, compromised, element of the STG’s grand vision — and with it, the U.S. manned space program.

In the pages of Voyage, the survival of President Kennedy in 1963 pushed history onto a track which diverged from our own trajectory: slowly, but sufficiently far, in the end, for the U.S. space program to reach out to Mars. The decision-making points depicted in Voyage closely parallel those in our own world. It could — with a small perturbation — have happened like this.

But even if the argument for Mars had been “won” in 1969, it would have been essential to maintain a supportive coalition of political forces behind a Mars program over the years, or decades, it would have taken to implement it — a period during which downward pressure on NASA’s budget was consistent. To reach Mars, NASA would have needed a Fred Michaels: another Webb — not another Paine.

And in many ways, an Apollo-style Mars program could have been a mixed blessing.

As Nixon foresaw, if the Mars program had come about, NASA would have been able to remain a one-shot, “heroic” agency, rather than move to the organizational maturity for which current Administrator Dan Goldin is still reaching. On the science side, Apollo dominated other space programs in the 1960s — often to their detriment. The Lunar Orbiter and Surveyor lander programs were effectively downgraded to serve as mappers for Apollo. Perhaps, if the Mars option had been followed, Viking might have been compromised in a similar fashion, and unrelated programs — such as the unmanned exploration of the outer planets — might have been put under even greater funding pressure.