The booster passed the launch tower. And, smoothly, Indigo Team took control of the mission from the Kennedy Firing Room.

Donnelly could feel adrenaline surge in his system.

“Roll and pitch program,” Chuck Jones called down on the air-to-ground loop. His voice was shaking, barely audible to Donnelly. “Everything’s looking good. The sky is getting lighter.”

The Saturn VN pitched itself over, arcing east over the Atlantic. The booster was flying itself, gimbaling its engines so that it neatly followed its preprogrammed trajectory; the members of the crew, Jones, Priest, and Dana, were passengers, their nuclear rocket just payload.

Natalie York, capcom for the shift, called up to the spacecraft. “Apollo, Houston… You’re right smack-dab on the trajectory.”

“Roger, Houston. This baby is really going.”

“Roger, that.”

Numbers scrolled across CRT screens, and Donnelly’s team talked quietly to each other on their comms loops.

It was York’s first assignment as capcom. She sounded calm, controlled; Donnelly was pleased.

The flight was going well. Rolf Donnelly could feel it. He didn’t have to do a thing.

There were a lot of unique features about this mission. It was the first time the U.S. had tried to maintain two ambitious flights at once, with no less than six astronauts above the atmosphere: Jones, Dana, and Priest climbing to orbit for their NERVA test flight on top of the Saturn VN, and Muldoon, Bleeker, and Stone already out in lunar orbit in Moonlab, waiting for their rendezvous with the Russians. It was also the first time NASA had operated both its MOCRs at once.

And this was, of course, the first manned flight of the S-NB, the new Saturn booster third stage with its NERVA 2 nuclear engine.

Management Row, behind Donnelly in the MOCR, was full today. For instance, there was Bert Seger, just over Donnelly’s shoulder, his trademark carnation a glare of white. And in the Viewing Room behind the glass wall at the back of the MOCR, Donnelly had spotted Fred Michaels himself, puffing on one of his cigars, watching the numbers unroll with baffled anxiety. This was a very important, and very public, flight.

But Donnelly wasn’t concerned; not now. He had a lot of faith in his people. The controllers in this room were actually leaders of the teams, three or five strong, who worked in the back rooms clustered around the MOCR; to get as far as this room, the controllers had had to work in the back rooms on a good number of missions. That was the way Donnelly had come up himself. The controllers would often get poached away by the higher salaries offered by the aerospace companies: a spell in Mission Control looked good on your resume. But that was all right; it kept down the average age in here.

Anyway, Donnelly had no such ambitions. The MOCR was much closer to the center of gravity of decision making, on any flight they’d launched to date, even than being in the cabin of the actual spacecraft. This was where things were run; in this room, Donnelly was in control. As far as he was concerned, it was better than flying.

One minute into the flight.

The vibrations of the launch smoothed out. We are outpacing sound itself, Jim Dana thought.

“You know,” Jones shouted, “there’s something…”

Ben Priest yelled back. “What?”

“This goddamn bird doesn’t ring right…”

Dana, staring at the panel before him, couldn’t see Jones’s face inside his helmet.

There wasn’t time to think about it. Gs were piling on Dana, as the five heavy engines of the S-IC stage continued to blast. Two, three, four Gs… he could feel his chest flattening.

But that was about as bad as it would get. In fact, the Gs were oddly reassuring. They were coming right on schedule. Maybe Jones was wrong. So far this was just like the sims. Almost.

Suddenly he was thrown forward against his seat restraints. What the…? The smooth buildup was gone. Could an engine have failed? But then he was hurled back, deeper into his couch; and then forward again, so hard he could feel his straps bruise his stomach and chest through the suit’s layers. Then back again -

“Pogoing!” Jones shouted. “Hang on to your hats, guys.”

The vibrations, forward and back, were coming at the rate of five or six a second, and their violence was astonishing. How many Gs? And oscillating all the time -

Dana could no longer see; the craft was a blur around him, and he felt as if he was being pummeled about the chest, head, and legs. We’ll have to abort. We can’t survive this. It’ll shake us to pieces. He tried to turn his head, to see if Jones was reaching for his abort handle.

The pogoing didn’t show up in the MOCR.

To the controllers there, the first-stage burn looked nominal. It was only apparent in the Marshall engineers’ equivalent of Mission Control, called the Huntsville Operations Support Center.

On a closed loop from Marshall, a warning was whispered to Mike Conlig. “The S-IC is pogoing. The accelerometers are showing plus or minus eight Gs.”

Conlig was sitting at the left-hand end of the Trench — the front row of the MOCR at Houston — working as the Booster controller for this launch, with special responsibility for the new NERVA stage. The pogo had to be occurring because the natural vibration of the thrust chambers of the F-1 engines was close, somehow, to the structural vibration of the stack as a whole. Christ, he thought. But we put in absorbers to de-tune the vehicle, this shouldn’t be happening. Evidently those assholes at Marshall hadn’t done enough resonance testing on the new Saturn VN stack, with its nuclear third stage. We could lose the mission because of this.

He prepared to report to Flight.

But the whisper from Huntsville came through again. “Amplitude diminishing.”

Conlig held his breath and waited.

The pogoing faded, as suddenly as it had begun.

By comparison, the steady pressure of three or four Gs on Dana’s chest was a welcome relief.

He saw the mission clock, hovering before him. Ten seconds. That’s all it was. Ten seconds.

He turned his head to see the others; there was a zone of blackness around his vision. He focused on Chuck Jones’s face. “Chuck? Ben? Are you okay?”

Jones’s hand was closed tight around the abort handle; Dana wondered what effort of will it had taken to keep from turning it. Jones said, “Houston, we’ve been a-pogoing. But we is still here, like three dried peas in a tin can.”

“Roger.” Natalie York sounded puzzled. It was possible the Houston people didn’t know, yet, what the crew had gone through. They didn’t see the accelerometer readouts. Dana just hoped they were watching the rest of the telemetry.

But then the events of the launch sequence came rushing on them. “Three minutes,” Jones called. “Get set for staging, boys.”

Dana shook his head, and the darkness at the edge of his vision began to disperse. He thought uneasily of the additional stress the staging would place on the pogo-rattled S-NB.

Rolf Donnelly had not enjoyed the pogoing. He had also not enjoyed not knowing about it until the crew’s verbal report came through.

At this stage of the flight, the Marshall people were more or less in control; they had the best understanding of the status of their bird. But I don’t know why we didn’t abort during that damn pogo. They must be really keen to get their nuclear stage into orbit.

Ascent to orbit was always the most difficult and dangerous phase of a mission: the phase when a hell of a lot of energy was being expended to get those tons of metal up to an orbital speed of five miles per second. Reentry was infinitely easier since you could dissipate all that energy at your leisure. Ascent was the phase when you were buying the most risk, the phase when Donnelly always braced himself for problems.

He felt he needed more control than he’d had on this flight so far.