Titan. Stephen Baxter
‘DPS?’
‘All four general purpose computers and the backup are up, Flight; all four GPCs loaded with OPS 3 and linked as redundant set. OMS data checked out.’
‘Surgeon?’
‘Everyone’s healthy, Flight.’
‘Prop?’
‘OMS and RCS consumables nominal, Flight.’
‘GNC?’
‘Guidance and control systems all nominal.’
‘MMACS?’
‘Thrust vector control gimbals are go. Vent door closed.’
‘EGIL?’
‘EGIL’ was responsible for electrical systems, including the fuel cells. ‘Rog, Flight. Single APU start …’
And so it went. Mission Control was jargon-ridden, seemingly complex and full of acronyms, but the processes at its heart were simple enough. The three key functions were TT&C: telemetry, tracking and command. Telemetry flowed down from the spacecraft into Fahy’s control center, for analysis, decision-making and control, and commands and ranging information were uploaded back to the craft.
It was simple. Fahy knew her job thoroughly, and was in control. She felt a thrill of adrenaline pumping through her veins, and she laid her hands on the cool surface of her workstation.
She’d come a long way to get to this position.
She’d started as a USAF officer, working as a launch crew commander on a Minuteman ICBM, and as a launch director for operational test launches out on the Air Force’s western test range. She’d come here to JSC to work on a couple of DoD Shuttle missions. After that she had resigned from the USAF to continue with NASA as a Flight Director.
As a kid, she’d longed to be an astronaut: more than that, a pilot, of a Shuttle. But as soon as she spent some time in Mission Control she realized that Shuttle was a ground show. Shuttle could fly itself to orbit and back to a smooth landing without any humans aboard at all. But it wouldn’t get off the ground without its Mission Controllers. This was the true bridge of what was still the world’s most advanced spacecraft.
She’d been involved with this mission, STS-143, for more than a year now, all the way back to the cargo integration review. In the endless integrated sims she’d pulled the crew and her team – called Black Gold Flight, after the Dallas oil-fields close to her home – into a tight unit.
And she’d been down to KSC several times before the launch, just so she could sit in OV-102 – Columbia – and crawl around every inch of space she could get to. As far as she was concerned the orbiter was her machine, five million pounds of living, breathing aluminum, kapton and wires. She liked to know the orbiter as well as she knew the mission commander, and every one of the four orbiters had its own personality, like custom cars.
Columbia, especially, was like a dear old friend, the first spacegoing orbiter to be built, a spacecraft which had travelled as far as from Earth to the sun.
And now Barbara Fahy was going to bring Columbia home.
‘Capcom, tell the crew we have a go for deorbit burn.’
Lamb acknowledged the capcom. ‘Rog. Go for deorbit.’
The capcom said, ‘We want to report Columbia is in super shape. Almost no write-ups. We want her back in the hangar.’
‘Okay, Joe. We know it. This old lady’s flying like a champ.’
‘We’re watching,’ the capcom, Joe Shaw, said. ‘Tom, you can start to manoeuvre to burn attitude whenever convenient.’
‘You got it.’
Lamb and Angel started throwing switches in a tight choreography, working their way down their spiral-bound checklists. Benacerraf shadowed them. She watched the backs of their heads as they worked. The two military-shaved necks moved in synchronization, like components of some greater machine.
Lamb grasped his flight controller, a big chunky joystick, in his right hand. ‘Hold onto your lunch, Paula.’
‘Don’t worry about me.’
Lamb blipped the reaction control jets.
Columbia’s nose began to pitch up. Benacerraf watched through the flight deck’s airliner-cockpit windows as Earth wheeled. The huge, wrinkled-blue belly of the Indian Ocean dominated the planet, with the spiral of a big swirling anticyclone painted across it.
Now Columbia flew tail-first and upside down.
‘Houston, Columbia. Manoeuvre to burn attitude complete.’
‘Copy that, Tom. Columbia, everything looks good to us. You are still go for the deorbit burn.’
Lamb replied, ‘That’s the best news we’ve had in sixteen days.’
Angel said, ‘The Earth is real beautiful up here, pal. I wish you could see how beautiful it was …’
‘Okay, let’s go for APU start,’ Lamb said. ‘Number one APU fuel tank valve to open.’
‘Number one APU control switch to start. Hydraulic pump switches to off.’
‘Confirm I got a green light on the hydraulic pressure indicator. Houston, Columbia. We have single APU start, over.’
‘Copy that …’
The APUs were big hydrazine-burning auxiliary power units. They powered the orbiter’s hydraulics system. During the launch, they had swivelled the big main engines, and now they would be used to adjust Columbia’s aerosurfaces during the descent. During its glide down the orbiter would be reliant on the APUs; without them, and without engines to provide power, it would have no control over its fall to Earth. The power units were clustered in the orbiter’s tail, beneath the pods of the OMS – rhyming with ‘domes’, the smaller orbital manoeuvring system engines which would slow Columbia out of its orbit.
‘Okay, let’s arm those babies,’ Lamb said. ‘Digital pilot to auto mode.’
‘Left and right OMS pressure isolation switches to GPC. Engine switches to arm/press.’
‘Gotcha. Houston, OMS engines are armed, over.’
‘Roger, you are go for burn countdown.’
Lamb scratched the silvery stubble on his cheek. He looked sideways at Angel. ‘What do you say? Shall we fire these old engines, or take another couple of swings around the bay?’
‘Aw, I’m done sightseeing.’
Lamb pressed the EXEC button on his computer keyboard. ‘Five. Four. Three. Two.’
There was a jolt, and a remote rumble, and then a steady push at Benacerraf’s back.
The CRT displays cycled between a complex display of the orbiter’s horizontal position, and a burn status screen.
‘… Hey.’ Angel shifted; something about his body language changed. He was looking at a panel in front of him. ‘I got a warning on prop tank pressure, in the right OMS engine pod.’
‘High or low?’
‘High. Two eighty-five psi.’
Lamb grunted. ‘Well, the relief valve should blow at two eighty-six. Anyhow, we only need another few minutes.’
The burn continued.
Fahy’s controllers saw the excess pressure immediately.
‘Flight, Prop.’
‘Go.’
‘I’ve got some anomalies in the right-hand OMS engine pod. The relief valve has just blown and resealed, the way Tom said. That brought us down