Titan n-2

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Titan n-2 Page 6

by Stephen Baxter


  “Then, when the burn came, and that slug heated up… The data’s chancy. The line might have exploded, Flight.”

  “What would that do?”

  “It would have gone off like a small grenade. It would have made a hell of a mess of the OMS engine pod. If the lines were ruptured, you’d have fuel and oxidizer sprayed all over that pod.”

  “But what about the second pod?”

  “Flight, there’s a crossfeed to take propellant from one pod to the other. We figure that’s how the fire crossed over. Maybe the slug was even in the crossfeed. There’s also a crossfeed to the RCS, from the OMS propellant tanks. We’re lucky we didn’t lose the RCS as well, before the burn was completed.”

  “Thank you.”

  “Flight, Egil. APU one and three temperatures still rising…”

  On it went. And now the surgeon started talking about the stress levels manifesting themselves in the biotelemetry from the orbiter. There wasn’t much Fahy could do about that, any more than she could manage down her own stress levels. And behind her, she could hear the MOD manager talking quietly into his microphone. The mission operations directorate manager was a link from the FCR to NASA and JSC senior management.

  It all continued to unravel.

  Fahy tried to get a handle on all of this, to make some decisions.

  None of her training, her experience, her orderly approach to contingency management, seemed to be helping her think her way through this. The problems here weren’t to do with her control, or with her team, but with the crummy technology which was falling apart in front of her. Even so, she was aware that she wasn’t handling this well, that Tom Lamb, with his fast decision to go for the reaction control burn, had actually achieved a lot more in this crisis than she had. With that action he might have saved the mission, in fact.

  Multiple failures would always get you; it was impossible to plan for every contingency.

  But maybe, she thought sourly, if the orbiter mission preparation process hadn’t been cut back to the bone, somebody might have caught this problem, before it blew up in their faces.

  The master alarm sounded again.

  Marcus White, Tom Lamb’s commander from his Apollo mission, was at JSC that day, for a Gemini fortieth anniversary dinner. When he heard what was going down over in Building 30, he came over fast. Now, he stood in the viewing gallery at the back of the FCR and watched as Barbara Fahy and her team of kids struggled to understand what was happening.

  Unlike Lamb, Marcus White had long since retired from NASA. After his Moon landing he was passed over for the Skylab missions and ASTP. He went into training for the Shuttle flights. But when the development delays started to hit, and the first flights were pushed back past the end of the 1970s, he got a little pissed off at kicking his heels around JSC.

  So he retired from NASA. At least his wife was pleased about that. He joined McDonnell Douglas out at Long Beach, and watched from outside as NASA and Rockwell between them royally screwed up the Space Shuttle program.

  If Columbia failed today, it would be a horror, but not a surprise, to Marcus White. He hated Shuttle; he always had. Its flaws went all the way back to the compromises that were involved in its design in the first place, back in the ’70s. You put solid rocket boosters on a manned ship, you’re going to get a Challenger. You turn your spacecraft into an unpowered glider for the entry, you’ll have this, a Columbia. His only regret was that now, in its final failure, Columbia might take Tom with it.

  Angel pushed the red button again. “APU temperature this time.”

  “There’s nothing we can do about that,” Lamb said briskly. “Let’s position for entry.” He grasped his control stick again, and pushed.

  Under the control of her RCS jets the orbiter somersaulted gracefully forward, briefly as graceful as a 2001 space clipper. Earth wheeled, the cabin light shifting, until the planet showed before the front windows.

  Columbia was facing forward now, her nose pitched up at an angle of about thirty degrees. Earth was spread out below the cockpit, a glowing blue carpet, subtly curved. The orbiter was the right way up, and descending.

  Suddenly, it started to feel like a landing to Benacerraf.

  “Houston, Columbia. We are in entry attitude.”

  “Copy that, Columbia. Looking good at this time. Are you ready for your entry switch checklist?”

  Lamb grinned at Angel. “Just like the other five times I’ve done this, Joe.”

  “I’m glad it’s you up there, Tom, if we’ve got to have a bad day.”

  “Wish you were here too, Joe. Okay, Bill. Cabin relief A and B enabled. Antiskid on. Nose wheel steering off. Entry roll mode off. Throttles full forward…”

  “Okay,” Lamb said. “Loading the entry software.” Confidently, as Benacerraf watched, he punched in OPS 304 PRO. Angel said, “Throttle to auto. Pitch, roll, yaw auto. Body flap to manual.”

  “Columbia,Houston. Rog. Moving right along, Tom. Nice and easy does it. We’re all riding with you.”

  “Roger that… Paula. Don’t miss the view.”

  Benacerraf leaned forward and peered through the picture windows. She could see no stars, and Earth was a carpet of city lights below the prow of the craft.

  She saw flashes of color, red and green.

  Angel grinned. “The lights of the reaction engines, reflected from the upper atmosphere. Pretty.”

  “Yes.”

  Lamb said, “Houston, Columbia, Entry interface.”

  Four hundred thousand feet, Benacerraf thought. The informal gateway to the atmosphere.

  Home again.

  The burn had knocked Columbia out of its orbit. But they were still more than five thousand miles from Edwards, still moving with a near-orbital velocity of Mach 25, and from now on without engines. After all they’d been through already — with a disabled engine system, and power units and RCS motors in an unknown condition — the key entry steps had still to come; the orbiter still had to shed most of its kinetic energy, and glide on home.

  Now Columbia, with a rattle of reaction control solenoids, levelled its wings, and tipped up to a new angle of attack.

  “Columbia,Houston. Ready for loss of signal.”

  “Yeah. See you at Mach 12, Joe.”

  A pinkish glow gathered beneath the windows, diffuse and pure, then deepening to orange. The orbiter was colliding with the thicker layers of air. The orange glow brightened, and turned white. In the corners of the windows, Benacerraf could see some kind of turbulent flow, swirls of superheated plasma. It looked like drops of rain on a car window.

  Now, for the first time in sixteen days, Benacerraf felt a feather-touch of gravity, a soft pressure pulling her down into her seat.

  The altimeter was steadily clicking off.

  The telemetry on the controllers’ consoles turned briefly to garbage, then blanked out. A static hiss filled the air-to-ground loop.

  All around the room, Fahy saw the posture of her controllers shift, subtly. They sat back from their terminals, from the suddenly empty screens, and stared at the big TV images of Edwards Air Force Base at the front of the room.

  The plasma shield building up around the orbiter would soon block all transmissions, voice and telemetry, between the orbiter and the ground. The blackout would last twelve minutes, on a nominal entry anyhow. During that time the ground would have no way of influencing events on the damaged spacecraft.

  And it was during the blackout that Columbia would become reliant on her aerosurfaces. It was entirely possible, Fahy thought, that if the power units failed now, Columbia wouldn’t emerge from her blackout at all.

  It was going to be a long twelve minutes. Fahy felt past and future hinge around her.

  It just shouldn’t be like this, Marcus White thought. We should never have built the Shuttle for the money they allowed us. We should have just refused.

  When McDonnell’s DC-X experimental rocket project came along — a step towards a new generation of launch systems — White
had just grabbed onto it.

  He liked working with the McDonnell boys again. It was a relief after NASA. McDonnell had built both Mercury and Gemini, and it was on Gemini that White had cut his teeth. And with the DC-X, just like with Gemini, the guys at McDonnell had rolled up their sleeves and got on with it. They built their prototype for just sixty million bucks: less than the cost of two replacement microgravity toilets on Shuttle, for Christ’s sake. White liked to say that the DC-X’s liftoff weight was less than that of the paperwork required for each Shuttle launch. And so on.

  But that had all changed, when the original McDonnell project ran out of money in 1993, and the DC-X was moved into the suffocating embrace of NASA. McDonnell had been forced to take the bird back to the factory at Huntingdon Beach, and bolt in all kinds of fancy modifications, like a new graphite epoxy hydrogen tank, a lox tank made from some kind of goddamn Russian aluminum-lithium alloy, and an oxygen-hydrogen reaction control system that used excess fuel from the main tanks.

  It was all typical NASA. Not one of these “innovations” had upgraded the bird’s performance, as far as White could tell; but they had all increased costs, reduced reliability, and sent the testing schedules spiralling off to eternity.

  White wasn’t surprised when, at the end of a test flight in 1996, they let the damn thing fall over and blow up.

  White just couldn’t understand it. To him, things were simple. You built ships, and you flew them. And you took the risks that went with it. That was all. He couldn’t see why the hell things should be any different.

  The truth was — in White’s view — the U.S. government was scared of developing cheap launch systems.

  An SSTO, a single-stage-to-orbit new-generation bird, would come up against a lot of vested interests. It took an empire of nine thousand people to launch the Shuttle, and a lot of money went flowing out of NASA to the contractors. That was a lot of turf to be defended.

  What if it was possible to demonstrate that you really only needed a launch and maintenance effort of a few percent of NASA’s huge investment? What if it was demonstrated that every country in the world could afford its own SSTO launcher, flying out of existing airports?

  The optimists said there would be an explosive expansion into space. Huge industrial efforts up there, new multinational stations, a fast return to the Moon. Blah blah. The military analysts said that von Braun visionary stuff was for the birds. What would be the military consequence of every tinpot country in the world having access to space? How about another Saddam Hussein?

  Private launch contractors weren’t pushing too hard either. One or two SSTOs could mop up the whole of the world’s launch capacity, and force all the existing commercial operators out of business.

  Nobody wanted SSTO. And that was why — as far as White could see — it was NASA’s job to kill programs like the DC-X: to kill it with bureaucracy, with study groups and change review boards and new, ineffective technologies.

  NASA’s purpose, consistent over three decades, was to block access to space, not to build for it. Which was why Marcus White’s good buddy Tom Lamb was up there now, hanging out his hide trying to save a thirty-year-old piece of shit called Columbia, risking his life for a monumental lie.

  It wasn’t good enough, for Marcus White.

  As angry as he’d felt in years, White made a decision.

  He marched out of the viewing area, and round into the FCR, and went straight up to Barbara Fahy. He’d been all the way to the Moon with Tom Lamb, he said, and now he was going to capcom Tom all the way home.

  Benacerraf was forced deeper into her seat as the orbiter shed velocity.

  Under the control of its guidance software, the orbiter tipped itself up, to change its angle of attack, and then banked slightly, to increase its sink rate into the atmosphere. Right now, the orbiter was flying blind, its external sensors overwhelmed by the plasma. Lights flickered over a panel ahead of Lamb, showing how the orbiter’s software was working the RCS jets.

  The idea of the antique, crippled spacecraft doing its level best to survive, to bring home its human cargo, was somehow touching, to Benacerraf.

  “I got ten psi,” Lamb said now. “Roll thrusters off. Here we go, twenty psi. Pressure climbing fast. Pitch thrusters off. Elevon control. Three hundred thousand feet.”

  “Maximum heating,” Angel said. “Our leading edges are up to three thousand degrees.”

  Columbia was already too deep in the atmosphere, now, to maneuver like a spacecraft with its reaction thrusters. From now on the orbiter had to fly like an aircraft: elevens, flaps in the trailing edge of the wings, would now control the craft’s pitch and roll. If the hydraulics worked.

  The sky was a rich, deep royal blue. Looking out, she could see the curve of Earth, and the closed curvature of the horizon. She could make out the whole of the western seaboard of the USA, it seemed, from San Francisco to Mexico.

  Columbia broke into sunrise, abruptly. Earth was still dark below, and the plasma glow was fading back to orange. Against the black landscape, she could still see the plasma glow, but where the sun was rising, there was a blue stripe on the horizon before her. For a second she was looking through the atmosphere at the sun, and shadows of clouds fled across the ocean towards her. But then the cabin was flooded with light, forcing Benacerraf to shield her eyes.

  …She’d felt like this once before. She rummaged through her memories.

  1969. A wonderful family holiday, up in the woods of British Columbia; she was ten years old, the perfect age to be a child. She hadn’t wanted to come home, to climb back down.

  She had the grim feeling that she would never, quite, get over the memory of all this wonderful light, and lightness.

  The Gs continued to mount, impossibly heavy. The deceleration pulled her down into her chair, and she felt as if she couldn’t keep her neck straight, as if her head was a huge, heavy box filled with concrete.

  The master alarm clamored again.

  Lamb punched it off. “What now?”

  Angel checked. “We’re losing hydraulic pressure, Tom. Shit.”

  And suddenly the orbiter dropped like a stone.

  “Flight, Egil. I got you a diagnosis on the APU situation.”

  “Go.”

  “We think we got a fire back there, Flight. In fact the system signature is looking a little like STS-9.”

  STS-9 had been John Young’s last flight. During the final landing approach on that flight, the power units had caught fire; all but one had failed on the way to the ground.

  Egil said, “Probably we have a hydrazine leak from one of the APUs. If that’s the case, we’ll have volatile hydrazine spraying over the hot surfaces in there.”

  “STS-9 was survivable,” Fahy said. “The crew got down safely and walked away.” That was true; the power unit fire — even a subsequent explosion — hadn’t been detected until the orbiter was back on the ground.

  “But on STS-9 the leak occurred just before touchdown. Here, the leak came a lot earlier, during entry…”

  “Flight, Prop. If we have had some kind of rupture of the OMS fuel lines, maybe that’s linked to these APU problems. The position of the APU tanks, in the tail section—”

  “Save it for the board of inquiry. Egil, Flight. What’s the worst case?”

  “That we’ll be looking at an APU loss scenario. We’ll have to recommend a ditch, Flight.”

  Fahy remembered, now, that the orbiter on STS-9 had been Columbia.

  For long seconds, it was like a roller-coaster ride — what the controllers called a phugoid mode — as the control system tried to stabilize the trajectory. When the oscillations stopped, the orbiter was still deep in blackout.

  Lamb flexed his gloved fingers, and closed his hand carefully around his hand controller. “Let’s see how this mother flies.”

  Benacerraf knew it was time for the first big maneuver in the atmosphere, a wide, banking S-turn. On a nominal descent, the automatic systems were generally allowed t
o fly the orbiter most of the way home. Today, it looked as if Tom Lamb wasn’t going to trust the automatics any more than he had to. Looking at the broad back of Lamb’s gloved hand wrapped around the control stick, Benacerraf felt obscurely reassured.

  “ADI rate switch to high. Roll/yaw switch to the control stick…” Lamb clenched his hand. He pulled the stick to the left.

  The orbiter banked to port. The Pacific tipped up, a glittering blue skin in the morning light. Shadows shifted across the cabin, sending complex highlights from the instrument surfaces.

  The master alarm sounded. Angel killed it. “We lost another APU, number three. Number one still online.”

  Lamb leaned into his control, and the orbiter pitched over further.

  “I’m only showing seventy degrees bank.” Lamb said. “It’s all I can get.”

  “You figure the elevens are screwed?”

  “It’s that low hydraulic pressure. Or maybe the last APU is going down. God damn this. I’m at the edge of the envelope, here.”

  Now, at Mach 18, Columbia rolled to the right. Below the prow, Benacerraf could see the coast of California, a brown line coalescing along the misty horizon, tipping up as the orbiter rolled.

  “ — Houston. Columbia, Houston. Can you hear me, Tom?”

  The blackout was over. Benacerraf felt a surge of relief, illogical, profound.

  Lamb said, “Columbia, copy. Holy shit, Marcus, is that you? How do you read?”

  “Columbia,Houston. We read you fine. Tom, we read you low on energy, and off the ground track.”

  “Tell me about it, I went phugoid back there and came out low energy. Houston, we’re down to one APU up here, and I think we may be losing hydraulic press. The elevens aren’t responding too well. Going into the second S-turn.” Lamb leaned to the left, dragging the control stick.

 

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