Against this background — and without a strong and articulate champion, the role served by Jack Kennedy in the novel — the Agency was soon forced to back off from its more aggressive proposals. The language in NASA’s draft report to the STG, prepared in April 1969, read: “We recommend that the U.S. begin preparing for a manned expedition to Mars at an early date.” By the published version the sentence had been watered down to: “Manned expeditions to Mars could begin as early as 1981” (my emphasis).

Agnew himself was, however, a champion within the White House of aiming for Mars — even though he was booed when he spoke of the project in public. White House counsel John Ehrlichman later described how he was unable to dissuade Agnew from including a 1981 landing in the STG’s list of recommendations, even though it was already clear that the Mars mission did not fit with the Nixon administration’s overall budget priorities. Agnew insisted on taking the argument in to Nixon. We do not know what Nixon said to Agnew, but fifteen minutes later, Agnew called Ehrlichman to explain that the Mars mission was being moved from the list of “recommendations” to another category headed “technically feasible.”

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.