Next a slim, cold-looking man, his blond hair speckled with gray, walked to the stage. “To achieve the necessary performance for interplanetary travel, we have evolved a ‘building block’ technology, in which separate NERVA propulsion modules will be launched into Earth orbit, and clustered to achieve different requirements…” The voice was shallow, a little clipped — overlaid by a disconcerting Alabama drawl, after all the years at Huntsville — but still underpinned by sharp Teutonic consonants.

This was Hans Udet: Udet, who had worked at Peenemьnde with von Braun and was one of von Braun’s senior people at Marshall.

Dana showed no reaction.

Dana had dealt with the Huntsville Germans many times, during his years at NASA. And he recognized, in the halls and offices of NASA, many faces from those ancient days in the Harz Mountains.

But he had never been recognized, in his turn — why should he be? — and he had never volunteered his identity. He had mentioned this antique link to no one. The Mittelwerk was buried deep in the past, and they had all moved on to new concerns.

He’d never even discussed that part of his past with Jim.

But he had never lost his sense of inferiority before the confident, clever Germans.

Udet put up foils showing two identical ships, to be assembled in Earth orbit. There would be four or six crew in each ship. The ships would be boosted out of orbit by disposable NERVA modules, and then docked nose to nose for the flight to Mars. Udet flashed up summaries of mission weights, flight durations, development costs, and other key parameters. “Our baseline study,” Udet said, “will allow us to launch to Mars in November 1981…”

It was a huge, grandiose scenario. Typical von Braun, Dana thought: unimaginative, brute force, overengineered.

Bert Seger opened the presentation up for questions. The hostile Houston contingent put in a lot of detailed probing about the untried nuclear technology: the difficulties of clustering the nuclear modules, progress on the advanced cooling techniques needed. There were also questions about the significance of the treaties banning atmospheric testing of nuclear technology; it seemed to Dana that those issues were still unresolved.

Seger let the questions run on for some time — well over the option’s allotted slot — and then orchestrated a round of applause. All of it reinforced Dana’s view that this was the mode preferred within NASA, unofficially, and Seger had a brief to make sure that it was fully understood and accepted.

The second major presentation was of an all-chemical-engine mode. It was prepared by Rockwell, and championed by Houston staff. Rockwell was, incidentally, the favorite to be selected as lead contractor for the Space Shuttle.

The mission profile, Dana soon saw, was close to the classic minimum-energy Hohmann transfer profile he’d sketched out to Jim, that day in the shop at the back of his house in Hampton.