York said, ‘Apollo-N, you are go for the burn.’
Apollo-N was drifting over the darkened Pacific; Ben Priest could see a bowl of white light in the waters below – the reflection of the Moon – and, all but lost in that milky vastness, the lights of a ship.
The crew lay side by side in their couches, cocooned in their pressure suits once more. Priest felt his heart pumping harder. We’ve done everything we can to check this damn bird out; now we have to go full bore on it, and that’s all there is to it.
At ten seconds the DSKY threw up a flashing ‘99.’ Chuck Jones reached out and pushed PROCEED.
Through the changing numbers on his console, Mike Conlig watched as NERVA’s nuclear core was brought back up to its working temperature. Liquid hydrogen was already gushing out of the big S-NB tank and pumping into the cladding of pressure shell and engine bell, and, Conlig knew, would be reaching the radioactive core about now, where it would be flashed to vapor as hot as the surface of a star.
The core temperature began to climb, following the curve laid out in the manuals –
No, it didn’t. The rise was too fast.
Conlig watched with dismay as his numbers drifted away from nominal.
As NERVA lit, the spacecraft shuddered.
Priest was pushed back into his seat with a long, gentle pressure. Perfect. Just like the sims.
Natalie York called up, ‘You’re looking good here. We’re hawk-eyeing your trajectory. You’re right down the center line.’
Priest’s job was to watch the pressure and temperature readouts from the S-NB stage, the NERVA engine and its big hydrogen tank. Jones was monitoring the attitude indicator with its artificial horizon, ready to take over the steering if the automated systems failed. Dana was calling out their increasing velocity from the DSKY readout. ‘Thirty thousand feet per second … thirty-three …’
Mike Conlig was aware of a deadly dryness in his mouth. On the loop from the back room, someone was screaming in his ear.
The numbers, white on a green screen, filled his world.
The computers worked constantly to update the numbers, and making sense of them wasn’t easy. He had to check the data-source slots at the top right-hand corner of the screen, to make sure that the sources of his numbers were all still updating him properly, and he had to be sure that he wasn’t diagnosing some problem incorrectly because of a mismatch in numbers of different vintages, fifteen or thirty seconds old.
But he discounted all that. He understood exactly what the silent parade of numbers was telling him. The NERVA core was still overheating.
He tried to increase the flow of hydrogen through the core. That would take away some of the excess heat.
He got no response. In fact, one readout told him that the volume throughput of the hydrogen was actually falling.
Maybe there was a problem with a hydrogen feed line. Or maybe a pump had failed. Or maybe it was his old enemy, cavitation, somewhere in the propellant flow cylinders.
The core’s temperature continued to rise. More screaming in his ear.
Damn, damn. He’d have to abort the burn. And this was probably the end of the mission; he doubted they’d be allowed to go ahead with another engine restart after this.
He sent a command to the engine’s moderator control. He would slow the reaction in the NERVA core, reduce the temperature that way.
He got no response.
If the temperature had gotten high enough, the fuel elements could have distorted, even melted, and it would be impossible to insert the control elements into the core. Was that happening already?
If it was true, there wasn’t anything he could do to retrieve the situation. As he watched his numbers evolve, Conlig felt the first touches of panic.
Priest could clearly see the cones of the volcanoes of Hawaii, upthrusting, broken blisters. Earth receded visibly, as if he was rising in an elevator. The ride was exhilarating.
He felt a surge of elation. The damn nuke works.
It unraveled with astonishing speed.
Conlig watched power surge through the overheating core. After that, the resistance to hydrogen flow through the core sharply increased. Bubbles built up everywhere. The nuclear fuel assemblies were starting to break up. Pressure rose abruptly in the propellant channels, which were also beginning to disintegrate.
The whole structure of the core was collapsing.
The pressure in the reactor began to rise, at more than fifteen atmospheres a second. And, because of the massive temperatures, chemical and exothermic reactions were starting in the core.
And now the increased pressure inside the reactor backed up to the pumps, and the pumps’ feedback valves burst. With the pumps disabled the flow of hydrogen through the core stopped altogether.
The reactor’s main relief valves triggered, venting hydrogen to space. That offered some respite. But the discharge was brief; unable to cope with the enormous pressures and flow rate, the valves themselves were soon destroyed.
And now the massive pressure was working on the structure of the pressure shell itself.
I’ve lost it. I’ve lost the reactor. It had taken seconds, for his life to fall apart. He tried to react, to think of something to do, to make a report to Flight. But his mouth was dry, the muscles of his jaw locked.
There was a loud, dull bang, and the Command Module shook: bang, whump, shudder.
Dana, strapped into his center seat, could feel the spacecraft quake under him. Hollow rattles and creaks sounded from around the cabin, a groan of metal as the can around him was stressed; it was a noise oddly like a deep-throated whale song.
The master alarm shrilled in Dana’s headset, a shrill of staccato beeps. Yellow warning lights lit up all over the control panels.
He turned to look at his companions. Jones was staring at the instrument panel, and Priest’s eyes were round. That sure as hell wasn’t routine, whatever it was.
Jones cleared the master alarm.
The feeling of thrust died abruptly. It was like a slow collision in a car; Dana was thrown forward, gently, against his straps.
Jones said, ‘Jim. The Main A light is on. Check it out.’
Dana looked at his console. A red undervolt light was glowing. Damn. I should have been the first to see it. The Command Module’s systems were Dana’s responsibility.
‘Confirm that,’ he said. ‘We’ve got a Main A undervolt.’ He was surprised his voice was level. He began to check voltage and current levels; they were showing erratic, inconsistent readings.
He heard pinging and popping noises. It was the sound of metal flexing. The spacecraft was still shuddering. Some damn thing has blown up on us.
Earth was wheeling past the windows. The Service Module thrusters ought to be firing, as the spacecraft tried to maintain its orientation. But he couldn’t hear any solenoids thumping.
Jones was talking to Houston. ‘Natalie, we be a sorry bird up here. We’ve got a problem.’ He unbuckled his restraints and floated up to the left-hand window. Dana knew he was following an old pilot’s instinct: at a moment like this, regardless of the telemetry, you needed to take a walk around the bird, to look for leaks and kick the tires, see for himself what was wrong.
Dana glanced out of the window to his right, past Ben Priest.
He saw sparks, chunks of some material, flying up past the Command Module. The material was glowing, red hot.
Now he could smell something, inside his helmet. It reminded him, oddly, of Hampton: his childhood, the ocean.
Ozone.
Donnelly didn’t even need to hear the specific words. He could feel the event, see it in the changed postures of controllers all over the room, hear it in the sudden urgency of their voices.
Something had fouled up. But at first the cause wasn’t clear; all Donnelly got was a rash of symptoms, monitored by his controllers.
‘We got more than a problem.’ That was EECOM, in charge of electrical and environmental systems: life support in Apollo-N. He was shouting
. ‘I got CSM EPS high density. Listen up, you guys. Fuel Cell 1 and 2 pressure has gone away.’ Controller jargon, for fallen to zero. ‘And I’m losing oxygen tank 1 pressure, and temperature.’
Natalie York was talking to the crew. ‘This is Houston. Repeat that, please.’
‘… We’ve got a problem,’ Jones said over the air-to-ground. ‘The NERVA is out, and we’re seeing a Main Bus A undervolt.’
‘Roger. Main Bus A. Stand by, Apollo-N; we’re looking at it.’
Now Guidance said, ‘We’ve had a hardware restart. We don’t know what it was.’
A hardware restart meant some unusual event had caused the computer to shut itself down and reboot. Donnelly called for confirmation from another controller.
The crew kept reporting their Bus A undervolt.
The electrical power for Apollo-N came from three fuel cells in the Service Module. The current from the cells flowed through the A and B Buses, conduits which fed the rest of the spacecraft’s components. An undervolt alarm meant the spacecraft was losing its electrical power.
Donnelly tried to get confirmation of the problem from EECOM. ‘You see a Bus undervolt, EECOM?’
‘… Negative, Flight.’
But EECOM had hesitated.
He knows more than he’s telling me. He’s still trying to figure it through. What the hell was happening here? The mission seemed to be falling apart before his eyes.
Donnelly pressed EECOM again; he needed more data. ‘The crew are still reporting the undervolt, EECOM.’
‘Okay, Flight. I got some instrumentation problems. Let me add them up.’
Instrumentation problems. EECOM sees the undervolt, all right. But he doesn’t believe what the instruments are telling him. He’s looking at a lot of ratty data; he thinks some kind of major telemetry failure is underway. He wants to be sure before he reports it to me.
Donnelly said, ‘I assume you’ve called in your backup EECOM to see if we can get more intelligence applied here.’
‘We have him here.’
‘Roger.’
Now INCO, the instrumentation and communications controller, called in. ‘Flight, INCO. The high-gain antenna has switched to high beam.’
What in hell did that mean? ‘INCO, can you confirm the time when that change occurred?’ If he could, it might be a clue in pinning down what was happening …
Before INCO could reply there was another call. ‘Flight, Guidance. We have attitude changes.’
‘What do you mean, attitude changes?’
‘The RCS valves appear to be closed. They should be open.’
Reaction control problems. Antenna problems. Problems with the oxygen tanks, and the fuel cells.
He’d never seen a systems signature like this before, not in any of the sims he’d gone through. But then, even after twelve years of flights, Apollo-Saturn was still an experimental system. You’d test-fly an airplane far more times than any spacecraft had ever flown, before declaring it operational.
So what was hitting him? It could be instrumentation problems, flaky readouts, as EECOM seemed to suspect. Or it could be that the Service Module had blown out, knocking the whole stack sideways. Or something else might have blown, and damaged the Service Module.
INCO’s timing came in. His antenna problems dated from a few seconds after they’d lit the NERVA.
For the first time in several seconds Donnelly glanced at the trajectory plot board. The spacecraft was diverging, markedly, from the path it should have followed, had the NERVA been burning smoothly.
The S-NB looked to have shut down.
‘Guidance, you want to confirm that deviation?’
‘Rog, Flight.’ Guidance was the ground navigator. Guidance must be looking at multiple problems too, as the spacecraft drifted from its trajectory, and tumbled away from its intended attitude.
‘Booster, you got anything to report?’
Mike Conlig did not reply. Donnelly could see how he was hunched over his console. ‘Booster?’
York said, ‘The crew is reporting a smell of ozone, inside their helmets.’
‘Flight, this is Surgeon. I have a contrary indication.’ The flight doctor on this flight was a crop-headed Oklahoman sitting in the row in front of Donnelly, with the systems guys, at the left-hand end next to Natalie York. He was wearing a button badge which read FUCK IRAN. His voice was taut, urgent.
Donnelly switched him onto a closed loop. ‘Go, Surgeon.’
‘Flight, I’m monitoring a surge of radiation flux through the spacecraft cabin. And some changes in the crew’s vital readings.’
Donnelly was thinking through York’s brief report. They can smell ozone. Oxygen, ionized by radiation. Radiation from the NERVA. Jesus Christ almighty.
It was real, then. Not just flaky instrumentation. And the Russians orbited a goddamn Vietnamese in Salyut this year. The press will crucify us.
Because of the two simultaneous missions in progress Bert Seger had been away from the office for three days, and he was taking a chance to work through his mail. He’d only been at it for a few minutes when he got a call on the squawk box, the line that linked up the senior staff in Building 2.
There had been some kind of problem with the Apollo-N flight, and Seger had better get on over to the MOCR.
Angrily Seger folded up his mail. With the NERVA, it was one damn thing after another.
The voltage needle on Bus A sank past the bottom of its scale. More warning lights came on.
Dana checked the Service Module’s fuel cell 1, which was supposed to feed Bus A. It was dead. His gloved fingers clumsy with the switches, Dana began to reconnect the Command Module’s systems from Bus A onto Bus B.
Now another red light came on. Bus B was losing voltage as well. He checked fuel cell 3, the feed for Bus B; it was dead too.
Jesus. We’ve lost the Service Module. It’s Apollo 13 over again.
He made his report, trying to keep his voice level. Mary would be listening, probably the kids. ‘Okay, Houston, I tried to reset, and fuel cells 1 and 3 are both showing gray flags. I’ve got zip on the flows.’
‘Acknowledged, Apollo-N. EECOM has copied.’
Earth, beautiful, unperturbed, drifted past the windows.
The spacecraft and booster had been set rotating by that mysterious bang. Dana knew the ship’s attitude control systems should have been trying to steady their slow tumble, but there was no sign of any correction.
‘Chuck, I think the Service Module’s RCS must be out.’
‘Rog,’ Jones said. ‘Houston, we don’t have reaction control, either from the Service Module or from S-NB.’
If the Service Module had blown, it was the end of the mission. But still, the crew ought to be able to get home, from this low Earth orbit.
As the spacecraft rolled, a cloud of ice crystals, sparkling, dispersing, drifted past the window to his right. It seemed to be venting from somewhere in the stack. It was quite beautiful, coalescing above the shining face of Earth.
More alarms lit up, as the problems multiplied and spread.
Donnelly had Surgeon feeding radiation dosimeter readings into his ear on the closed loop.
EECOM said, ‘Flight, I want to throw a battery on Bus A and Bus B until we psyche out the anomalies. We’re confirming undervolts.’
Donnelly tried to shut out Surgeon’s voice so he could figure out EECOM’s suggestion.
EECOM wanted to run the Command Module off battery power. It was a reasonable short-term suggestion. But, looking ahead, the Command Module’s batteries would have to be conserved to allow the crew to reenter the Earth’s atmosphere. ‘What about limiting that to a single Bus, rather than both?’
‘Hold on that, Flight.’ EECOM would now be conferring with his team of experts in the back rooms.
It was obvious from multiple indications, not least the crew’s report, that the NERVA had indeed shut itself down after only a few seconds of the planned burn. ‘Booster, you have anything you want to say t
o me?’
Conlig didn’t reply. The guy seemed to have frozen out.
‘The crew’s health is going to be severely impacted,’ Surgeon said on the closed loop. ‘Though they probably don’t know it yet. In fact, Flight, you can’t expect them to function normally for much beyond a few more minutes.’
Guidance came on line. ‘The bird’s attitude is still changing. They got to stop it. We’re heading for gimbal lock.’
‘I hear you, Guidance.’
Gimbal lock meant the spacecraft tumbling beyond the tolerance of the inertial guidance system. The platform could be reset by eye again. But if Donnelly was forced to go for an emergency reentry, he needed alignment control now.
Somehow, though, he felt that alignment loss, even a gimbal lock, was the least of the spacecraft’s problems right now.
‘Houston, Apollo-N.’ It was Jim Dana; to Natalie York, Jim’s voice sounded thin, frail, but controlled. ‘We’re seeing some kind of gas, venting from the stack.’
York’s skin prickled with a sudden chill.
‘Rog, Apollo-N,’ she said. ‘Can you tell if it’s coming from the S-NB tank, or the Service Module?’
‘We can’t tell. Both, possibly.’
She’d been following the controllers’ terse dialogue. The controllers were still working to the assumption that there was some kind of instrumentation or telemetry problem here, to explain the multiple anomalies.
But if the ship was venting gas, that couldn’t be it. The problem couldn’t be just instrumentation or an electrical screw-up. And besides, she could see that Surgeon, next to her, had switched onto a closed loop.
Something, some violent and destructive event, had happened to Apollo-N, up there in low Earth orbit, to a spacecraft with a nuclear pile attached to its tail.
She glanced across at Mike. He was still hunched over his console and whispering into his headset. Why doesn’t he say something to Flight?
She became aware that her right hand was clutching the thin metal maintenance handle of her console; her hand was closed into a fist, painfully.
Her throat was dry, and she had to force herself to swallow before she could speak again.
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