Udet’s eyes were pale blue behind his glasses. The German studied Dana, analytically, as if computing the way forward. Then, every movement evidently calculated, he sat down beside Dana; he sat easily, with his arms open, in a friendly and welcoming posture. “I understand your concerns, Dr. Dana; I have read the memoranda you have prepared for Bert Seger. My purpose today is to alleviate those concerns — to assure you that they are groundless.”

Despite himself, Dana felt disoriented by Udet’s control, his Prussian-aristocratic command. Dana’s glasses had slipped; he pushed them back and tried to speak forcefully. “And my concern is that no compromise in safety be made, for the sake of subsidiary goals such as reusability, or schedule, or economy.”

“Of course. And if I—”

“Can we return to the question of the launch?” Fumbling in his case, he extracted a brief, handwritten note. “I have completed a preliminary analysis of some failure modes during launch. I will, of course, document this formally.”

“I’m sure we have considered every failure mode, Dr. Dana.”

“I’m sure you have, too,” Dana murmured. “But perhaps we could review this. As an example: it appears that just before launch the Solid Rocket Boosters, and the rest of the stack, will be subject to what my son calls a ‘stretch’ — when the MS-IC’s engine fires up a few seconds before the release of the stack’s hold-down posts.”

Udet’s smile was thin. “I am familiar with the astronauts’ term.”

“The structural loads stored in the assembly by this ‘stretch’ will cause the whole stick to vibrate on release, shivering back and forth for the first few moments of flight, with a period of three or four seconds.” Dana prodded at a part of the page he had underlined heavily. “According to this rough outline, you will see that the greatest stresses on the joints of your segmented rockets are likely to occur during the ‘stretch’ and the subsequent bounce; I believe the stresses at that time might even exceed those of the period of maximum dynamic pressure during the flight.”

“The joints are designed to resist such pressures. All of this is under consideration,” Udet said, sounding a little testy.

“I’m sure it is. But I will want to see documentary evidence of tests before I could consider signing off the Critical Design Review. I have further recommendations.” He dug out more pieces of paper. “I would like to see the rubber of the segment seals replaced with a composite, temperature-resistant material. The field joints should be redesigned. All of this will reduce the possible flexing of the joints during the ‘stretch’ by many orders of magnitude. In addition, viewing ports for launch-site testing and electrical heating for the joints should be installed…”

As he went through his points, Udet listened politely, imperturbable.

A new announcement, incomprehensible to Dana, came over the sound system, and Udet turned his head to listen. When he turned back to Dana his smile was restored, creasing his papery cheeks. “We will talk further,” Udet said. “But the test fire will begin in a few minutes. If you will accompany me — you may bring your drink if you wish…”

Dana followed. Oddly, he felt as if he had acted without manners — as if it had been crass to raise all those niggling objections on a day of such visionary significance.

Udet drove Dana out to the test range in an open vehicle like a golf cart.

They stopped perhaps a mile from the booster. Udet, with an outstretched hand, helped Dana from the cart, and then to climb down a short metal ladder into an open trench. The trench was maybe four feet deep, a crude affair lined with rough-finished concrete. A technician handed Dana a set of goggles and a white hard hat.

The test booster was a cylinder of slim white, lying flat against the orange ground. The booster was strapped to the Earth by huge rectangular frames, and its nose was capped by an immense, open half sphere. As if it is a fallen god, pinned down, which might otherwise escape. The field joints between the casing segments gleamed gold in the sun, which was climbing toward noon. The big engine bell flared toward a low hill.

Men walked around the booster, dwarfed by its white flanks; instruments and cameras, mounted on delicate-looking tripods, clustered about the rig, and there were probes inserted into the black mouth of the engine bell itself.

Udet tapped Dana’s shoulder and leaned toward him. “We still have a couple of minutes. Let us speak freely, you and I.”

Dana studied him suspiciously.

Udet said, “I want to talk about risk. I think this lies at the heart of the debate we are engaged in. We have accumulated, in this country, the best part of two decades’ experience in designing and operating manned spacecraft systems. And in that time, the concept of risk has—” Uncharacteristically Udet hesitated, evidently searching for the right word.

“ ‘Evolved’?” Dana suggested drily.

Udet arched an eyebrow. “Very well. ‘Evolved.’ We have found it necessary to develop principles more sophisticated than simple admonitions to ‘protect the crew at all costs,’ and so forth.”

“ ‘We’?”

“Yes,” Udet snapped. “We who are responsible, ultimately, for the safety of the young men we loft into orbit, as opposed to those — with all respect — who merely stand to one side. Such as yourself.

“The evaluation of ‘risk’ itself evolves during the progress of a mission. Consider this. The Apollo 12 booster was hit by lightning during launch. The spacecraft reached orbit safely, but Apollo’s electrical systems had been severely battered, and it was impossible to check if the parachutes in the Command Module would function correctly. On balance, it was decided to continue the mission; once we have survived a launch, however problematic, if we do not proceed we must subject another crew to the greater risks of a further launch to reach the same point. And as for the parachutes, if a return to Earth would kill Conrad and his crew, it may as well be after a lunar landing as before.”

“I know the story, Dr. Udet. What is your point?”

“Simply that this whole business” — Udet waved a hand — “is just the realization, the fabrication in metal and rubber and cryogenic liquids, of a dream. A dream which you and I share. But it is not a dream which can be achieved without risk. Our mission, therefore, is not to eliminate risk but to manage it. And it is this perspective which must inform your review of the project…”

Dana felt uncertain, once more, in the face of Udet’s calm competence and assurance. Could he really oppose this man’s powerful convictions?

Over a remote PA, a countdown began. Udet stood upright in the trench, his silver hair shining in the sunlight. It is for moments like this that Udet is alive, Dana thought.

“Later,” Udet murmured to Dana, “I would like to show you the manufacture of the propellant, here at Wasatch; the compound is mixed in great bowls and then poured straight into the casing segments. It has the look and feel of rubber…”

Thirteen. Twelve. The rocket was clear of personnel; it lay alone and shining on the desert floor.

“…The final compound will ignite only under extreme heat, and is not sensitive to static, friction, or impact. It is very safe, you see.”

Six. Five.

“Indeed, a small rocket motor is required to fire inside the casing to ignite the propellant. And once ignited there is no need for pumps, or cryogenic storage; a solid rocket simply burns…”

Yes. And, once lit, it can’t be doused.

Two. One.

White flame lanced from the engine bell in an instant of eerie silence. The flame reached out toward the bland hillside behind the tethered rocket, and to Dana, dazzled, it was as if the desert sunlight had been dimmed, the blue and orange of the landscape leached to gray by comparison with that fire — rocket light, hotter than the surface of stars — which humans had brought to Earth.