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.
The trouble was, the Marshall Germans had developed their skills in an era of automated, unmanned vehicles. You couldn’t send a command to a V-2 once it was off the pad. And the thought of trying to control a bird in flight was still alien to them. So the Germans had done their best to turn their controllers, the people involved, into robots — extensions of the machine. Don’t improvise. Be disciplined. Follow the book, you’re paid to react, not to think.
Donnelly made a silent vow that he would campaign to have procedures changed. He didn’t want to be put in the position of having to trust the judgment of the Marshall people again.
Still — although the Saturn was riding a little above its planned path, on the big trajectory plot at the front of the room — the crew seemed to have ridden out the pogo, and the booster’s telemetry looked nominal. The stack had survived its first staging, the discarding of the spent S-IC, and the second-stage burn looked smooth.
Maybe we’ll get away with this…
Donnelly could feel a pressure on his back. There were men in that Viewing Room, among the VIPs and celebrities and headquarters people and politicians and crew families, who would know things were going wrong. There was Fred Michaels himself, with his nose practically pressed up against the glass. And beside Michaels was Gregory Dana, Jim’s father. Donnelly didn’t know Dana senior personally, but he understood he was some kind of mission specialist from Langley. The pressure exerted by the man was worse even than anything induced by the presence of Michaels. Goddamn it, that’s my son up there.
Donnelly was a man on the climb. He looked forward to a bright future — a few more years there in the arena, then maybe a move up into program management. And when he’d pulled off this complex and difficult mission, it would be one hell of a feather in his cap.
He loved his job. He wanted to go a lot farther; he wanted to run the flight to Mars. He did not want this mission to fail.
It was time to light the nuke.
Apollo-N shuddered as explosive bolts severed the spent S-II second stage. Dana drifted, weightless, waiting for the next kick.
“Here we go again,” Jones said. His Tennessee twang was calm and relaxed — as if he does this every day.
Well, Chuck Jones could playact his calmness all he liked; but even he had to be wound up tight as a watch spring, Dana thought, because the most important moment in the flight was approaching. The third stage of the stack was not the old reliable S-IVB which had carried the Moon missions to Earth orbit and beyond; it was an S-NB, with the first operational NERVA engine. And the damn thing was going to have to work to get them to orbit, Dana knew, or they were going to be flying across the Atlantic to a hard landing in the goddamn Sahara.
York called up: “Apollo, Houston, you are go for orbit. You are go for orbit.”
For long seconds the spacecraft soared, without acceleration; and then, at last, Dana was kicked in the back.
“She’s lit,” Chuck Jones breathed. “How about that. We’re flying a goddamn nuke.”
The NERVA burn was nothing like so jarring as the second-stage ignition six minutes earlier; the ride was crisp and rattly, with just two hundred thousand pounds of thrust pressing a full G into his back.
And then Earthlight strobed past Dana’s window. The Apollo had dipped toward the ground.
He was thrown forward against his restraints, the breath knocked out of him. My God. What now?
The nose of the craft pitched up again. Metal groaned, and Earth’s brilliant face swooped past his window. His helmet thumped against the sparse metal frame of his couch. Blue light flashed over his visor.
Chuck Jones’s voice was dry. “We’re riding a bronco here, Houston. Please advise.”
“Booster, Flight. Tell me what you’ve got.”
To Donnelly, it looked as if the little Saturn icon on the plot board was drunk, as it wandered crazily around its programmed trajectory. A dozen voices jabbered in Donnelly’s ear at once; he listened to them all, somehow simultaneously, trying to piece together what was happening.
But the most important voice wasn’t there. Mike Conlig wasn’t speaking to him.
“Booster, Flight,” he repeated. “You got anything you want to say?”
Even without Conlig he could follow the bones of what was happening. The S-NB seemed to be working nominally, in fact. The pitching must be due to leftover problems from the pogoing. The vehicle had been tipped up too high when staging came. So when the S-NB cut in, it found itself pointing too far into space. It had gimbaled its nuclear engine, and tried to point its way toward the center of the Earth. For long seconds the guidance system battled with the limits of gimbal on the engine. And then the S-NB seemed to figure that its path had gotten too low, so it pitched itself up again…