Titan n-2

by Stephen Baxter

  We all let ourselves get so damn old, White thought gloomily.

  A countdown was proceeding, delivered by a smooth woman’s voice. It sounded like the announcements in an airport departure lounge.

  Donny Baylor was sitting in the front row of the stand, pale as a ghost, with his face half-covered by the biggest, thickest pair of sunshades White had ever seen.

  White laughed and clapped Baylor on the back; Baylor blanched further.

  “Asshole,” Baylor said.

  “Not as young as you used to be, Donny.”

  “Neither are you.”

  White settled into a seat beside Baylor. “I’ll tell you the best damn hangover cure I ever knew. You’d take up your bird after a night of throwing them back, with all that alcohol still sloshing around your system. All you’d have to do was pull a few Gs and suck in oxygen to flush all that crap away…”

  Baylor was a short, stocky man, and his face was a round, wizened button. He rubbed his forehead and scratched at the grizzled frosting that was all the years had left of his hair. “Things have changed, Marcus. When you think about it, it was pretty much you and me on our own last night.”

  “Too damn true,” White said. In fact, he had a theory you could correlate the nation’s decline with the growing adversity of these younger generations to a few cold ones.

  Baylor checked his watch. “Ten minutes to the firing.”

  White looked out of the picture window. The sun was low and in his eyes, but the glass was polarized somehow. There was a small pair of binoculars in front of his seat, not much bigger than opera glasses. But when he lifted them to his eyes some kind of electronics in the optics started to work, and the test stand leapt into his view, as detailed as if he was standing next to it, the image as steady as a rock, the glasses somehow compensating for the shake of his hands.

  The test stand itself was just a big square block of scaffolding, sitting on concrete trestles over a flame pit, anchored deep in the desert. The stand was maybe forty feet tall, and it was topped off by the two big silvery spheres which held oxidizer and propellant, RP-1 kerosene, for the test fires. There was frost, sparkling over the shell of the liquid oxygen tank.

  The single F-1 engine under test today — a complex tangle of feed lines, electronics and gimbal bearings — was pretty much hidden by the test stand structure. But he could see the nozzle, protruding out beneath the scaffolding, and he could see the fat kerosene pipes wrapped around the bell; the fuel passed around the combustion chamber and engine bell, to cool them, before it was fed into the combustion chamber.

  That single nozzle was all of twelve feet across. And a Saturn first stage would have no less than five of those mothers, in a neat cluster, all burning at once, every one of them five times as powerful as the Atlas rocket that had thrust John Glenn to orbit.

  Even the test stand itself had had to be refurbished for this program, he knew. Most of the Saturn test facilities around the country had long been deactivated or converted to other uses. The Rocketdyne engine stands at Canoga Park had been converted for tests of the Atlas and Delta expendable boosters, for instance, and the stands here at Edwards had been used for Shuttle solid rocket motor tests. The Marshall facilities had been turned over to Shuttle main engine tests. And so on.

  Well, to make the schedule, this reverse refurbishment had been brisk, he could see now. The desert sand around the test stand had been churned up, and left in great untidy heaps.

  Beyond the stand, a line of worn, rocky hills shouldered over the horizon; the sky was high and blue, with a few wisps of cloud in layers. There was a great sense of emptiness, of bigness; White knew there wasn’t a human being within a mile of that stand.

  “So, Donny,” White said. “That damn thing going to light on schedule?”

  White was expecting the usual confident good-guy bull back from Baylor, and he was surprised when Baylor didn’t respond in kind. Instead Baylor glanced at him, evidently troubled, despite that big mask of his sunglasses. “I’ll tell you the truth, Marcus,” he said. “We got ourselves one hell of a beast out there.”

  “You don’t sound too confident.”

  “I’m not. Christ, Marcus, it’s been like archaeology. We had to tear down one of the old flight spares for the component evaluation, and to get some experience of assembly and checkout. We had to buy fresh tooling and checkout equipment, and activate the old turbopump checkout facility. We had to adapt the thrust chamber assembly equipment we use for Shuttle main engine production. Only about half of the old suppliers are still in business, so we had to find new approved suppliers, for the heat exchanger duct assembly, the lox mating ring, the fuel pump housing, the pump housing machining… A dozen things. Some of the tools we needed we had to make. We had to redraw the tooling drawings, rework all the process and material specifications; they weren’t compatible with the manufacturing processes we use now…

  “I’ll tell you what’s really screwing us, though. Instability in the combustion chamber. See, the pumps bring the lox and kerosene to the injector plate. That’s a metal slab, a disc a yard across and four inches duck. The point is to get a nice smooth flame front, where the propellants burn at a uniform temperature, right across the face of the injector plate, all three feet of it…” Baylor started going into a lot of detail about how the lox and kerosene were brought into the chamber as fans, which impinged on each other. Pre-burners ignited the propellants at those points of impingement. Baylor mimed the little fans of lox and kerosene with his engineer’s hands, his gnarly fingers splayed out, as brown and hard as wood carvings.

  “And if you don’t get a smooth flame front,” Baylor said now, “you’re fucked. Suppose one side of the plate has a slightly higher oxygen content than the other. Then that area will get hotter, and produce higher pressures on that side. Then, in an engine the size of the F-1, you get a racetrack, where you have a high-pressure wave rushing around the perimeter of the combustion chamber. Then — it only takes milliseconds — the heat flows inside the chamber get disrupted and start bouncing back and forth. You get positive feedback, and before you know it your combustion process is out of control. That’s combustion instability, Marcus.”

  “So why are you telling me about it?”

  “Because it’s killing us. The slightest thing seems to trigger it: cavitation in the pumps, thermal shocks as the engines heat up, acoustical shocks at the moment of ignition.”

  “But that kind of instability can’t have been a new problem, even in 1961,” White said.

  “Hell, no. The Germans had instability problems all the way back to the goddamn V-2. Each generation of rocket required new fixes. But all of the fixes were pretty much ad-hoc, Marcus; nobody really had a handle on it. And with the F-1 you had this immense size of engine to compound the problem. Maybe,” he mused, “if we’d left well enough alone, and not fucked about with the configuration… but we didn’t. We’re trying to upgrade, to reach eighteen hundred K thrust, up from fifteen hundred. So we’ve made a whole stack of modifications: we increased the oxidizer inducer diameter, strengthened the gimbal seat and the cross block, strengthened the high pressure ducts and the thrust chambers, beefed up the turbine exhaust manifold, improved the heat exchanger, increased the power of the turbine… All of that screwed the stability of the flight configuration, basically. And we’ve had to try to fix it.”

  “Come on, Don. Those old guys in the 1960s, from Rocketdyne and Marshall, got the instability problem licked in the end. I mean, with due respect, I’m looking at one of those old bastards right now.”

  Baylor looked mournful. “That’s just it, Marcus. I arrived too late. I came into propulsion engineering at Marshall in 1965, just about in time for the Saturn flight testing. I missed all the fun, from the early days, when the core team — the Combustion Devices Team — was working to solve the instability problem.”

  “Don’t we have any members of that team left?”

  Baylor looked grim. “Marcus, they even sent
me around the old people’s homes. Most of those guys are dead, and the rest are eating baby food and complaining about their catheters. Hell, you’re talking about a project that’s nearly fifty years gone. I was just a junior member of the team — and I joined late — and now I’m the most senior guy we have here.” He shook his head. “If only we’d thought to do this twenty years ago — even ten…”

  The count reached its final seconds. Baylor turned to the test stand, and picked up his binoculars.

  In the last moments, tons of water cascaded down, into the flame deflector pit at the base of the stand. White could hear the roar of that miniature Niagara even from here, even through the glass.

  Baylor didn’t seem aware White was here any more; his eyes, behind their big shades, were focused on that test stand.

  White could picture what was happening inside the F-1.

  The combustion chamber, the tough heart of the engine, was a barrel a yard wide and a little less long. Right now, a few seconds before ignition, four small pre-burners inside that chamber — pilot lights — had lit up, providing a flame at the points where the sprays of lox and kerosene from the injector plate hit each other. The burning of exhaust gases from the turbines produced a thick orange smoke, which burst out of the nozzle and bounced off the flame deflector under the launcher, busting out to either side. The pumps were running up to speed, the valves were opening, and now the propellant poured in: a ton of kerosene, two tons of lox, in the first second alone, and in every second thereafter.

  The gases produced by their ignition shouldered out through the nozzle throat at the bottom of the chamber. In these few seconds, as the engine built up to full power, the interior of the combustion chamber went from room temperature to as hot as the surface of the sun; pressure went from zero to a thousand pounds per square inch.

  The flame directly under the engine turned to an incandescent white, and the orange smoke billowed outward and upward, enveloping the base of the nozzle. A pillar of pure white light exploded into life under the engine bell.

  It was the brightest thing in White’s view, brighter than the sun. His binoculars dimmed themselves down, compensating for that surge of brilliance, obscuring the rest of the test stand structure and dimming the bright blue sky to a muddy grey. The water gushing into the flame pit flashed to steam, and great clouds of it billowed out around the stand, unable to dim the brilliance of that light.

  The noise reached them now, a great crackling explosion of nonlinear wave fronts that burst across the desert. The picture window rattled, visibly bowing, and in the depths of his gut White could feel a bass rumble.

  White felt his lips pull back into a feral grin, and he whooped. He just let all that pure rocket light wash over his face. This was the way a rocket was supposed to be, he thought: pure liquid fire, none of that dirty yellow-orange shit that came spewing out of the solid-propellant firecrackers they strapped to the side of the Shuttle.

  But then the torrent of fire sputtered, as if the engine was being throttled back, or was stalling. White thought he could see the whole test stand shudder.

  The nozzle softened and deformed.

  It happened in an instant: thick, high-strength steel plate burning through in a quarter of a second, guttering like candle wax. The metal just gushed down into the flame pit, swept away by the energy of the torrent of fire. And then that torrent, without the shaping of the nozzle, turned from a controlled explosion into an uncontrolled one.

  Light gushed out of the test stand in a ball, flaring; steam billowed furiously. He thought he could feel the heat of the bang on his face, even across a mile of desert, even through the toughened glass. It was like a nova, White thought, a star exploding on the Earth.

  The explosion lasted no more than a second. Then the test stand shut itself down, cutting off the flow of kerosene and oxidant to the failed engine.

  The light faded, leaving the test stand exposed, huge clouds of steam still billowing up out of the flame deflector.

  Baylor lifted his glasses and rubbed his face; White could see that his eyes were red-rimmed and rheumy, glossy with water. The eyes of an old man.

  “Fuck,” said Baylor. “See what I’m saying about the instability.”

  All around them, in the viewing bunker, the technicians and managers were moving out, with much gloomy talk and shaking of heads.

  Now’s the time for a bit of inspiration, Marcus. This is why you’re here. Sprinkle a little of the old Moondust on them, and get them all fired up to go out there and take that motor to pieces, and go over it again and again until they get it right.

  Like they used to in the old days.

  But right now, damn his soul to hell, he couldn’t think of a thing to say.

  Outside, around the ruined test stand, the steam clouds continued to billow out of the flame deflector. Mojave sand was scattered around the test stand in rays: dead straight and maybe thirty feet long, reminding him of the raying on the lunar surface, around his LM descent stage, after the landing.

  * * *

  This wasn’t like preparing for any other flight, Siobhan Libet found. This wasn’t just routine, just another element in the assembly-line of Shuttle missions.

  It wasn’t just that it was the last. With this flight, she was entering realms of mythology. People looked at her differently.

  And everywhere she went she faced the classic, unanswerable question. What’s it like to fly in space?

  She went up to Boeing’s Shuttle orbiter assembly facility, at Palmdale, California.

  Libet tried to remain inconspicuous as Billy Ray Jardine of Boeing conducted his tour. That wasn’t too difficult at first; the little ten-strong group, of astronauts, NASA Shuttle and Titan program managers — including Libet and Barbara Fahy — were anonymously clad in bunny suits, long, crisp-white coats and hygiene-conscious caps. They looked, Libet thought wryly, like a group of food hygiene inspectors descending on a McDonald’s.

  The Palmdale assembly facility was huge, cavernous, a place of light and rectangles. The floor was a layer of some blue-grey resin, utterly flat, threaded with yellow demarcation lines and scarred with rubber skid marks from the little electric carts that rolled everywhere. The walls were painted with corporate red, white and blue stripes and huge Stars-and-Stripes. Around the edge of the floor were big, cuboid offices, like independent buildings spawned inside the gut of this monster, and the floor was littered with massive, anonymous machinery.

  Billy Ray Jardine was the President of Boeing’s space transportation division. Jardine looked every bit the corporate senior executive, with his grey suit jacket stretching over his ample, comfortable belly. He would have fit in just about any era since the Second World War, Libet thought; his type had been running the country for much longer than she had been alive. Only the full-color images cycling across the surface of his softscreen tie — of old successes in space, Rockwell’s Saturn V second stage, Apollo, Shuttle itself, not to mention Boeing’s own Saturn V first stage — gave any concession to modernity.

  The facility was clean, bright, every metal surface shining and unscuffed. The assembly and manufacturing equipment around her looked state of the art. Here — by Rockwell, before the Boeing buyout — all five of the billion-dollar spacecraft of the Shuttle fleet had been assembled, from Columbia to the Challenger replacement Endeavour, which had first flown in 1992. And Boeing had evidently maintained this facility to the highest standard. Any time NASA had asked for a revival of the Shuttle construction program, Boeing would have been able to respond, ready to accept all those fat billion-buck NASA contracts once more.

  But Libet felt depressed by all this sparkling readiness. Because this facility was never going to be used to build an orbiter again.

  In fact, Boeing had adapted its facility to tear spacecraft apart.

  The party was taken to a metal balcony which overlooked a sectioned-off part of the assembly area floor. Here, the Shuttle orbiter Atlantis had been brought for its hasty modificat
ion. The orbiter’s boattail — the aft fuselage assembly — was facing Libet, with the nozzles of the three big main engines thrusting out of the scaffolding. The rest of the orbiter, foreshortened by perspective, was encased in scaffolding and protective sheeting. A little swarm of white-coated workers was busy all over the spacecraft; the air filled with the whine of drills and the ozone stink of oxy-acetylene burners. Atlantis looked, Libet thought, as if it was being deliberately crippled.

  At first glance, the orbiter itself still looked much as it had done before. But, slowly, Libet made out differences.

  For instance, the crew cabin — the nose of the orbiter — had been dismantled. Now, a simple aerodynamic cone fairing was being fixed to the orbiter’s frame. And Atlantis’s payload bay had been lengthened, into the space vacated by the crew compartment, to more than eighty feet: a third more than the baseline design of the Shuttle system. The boattail, with the main engine assembly, was being left almost unmodified. But the smaller engines of the orbiter’s orbital maneuvering system had been removed. Those engines brought the ship out of orbit at the end of its mission. And there was no need for a system to bring Atlantis home again.

  And Atlantis had no wings.

  Atlantis no longer needed wings, or a tailplane, or retro engines. Atlantis was no longer an orbiter. She had been reduced to a Shuttle-C Cargo Element, a so-called SCE, consisting of little more than a payload carrier bay and an aft fuselage, with engines. And SCEs were expendable. Atlantis would never again carry a crew. No effort would be made to return Atlantis to Earth after her final flight; its cargo delivered to orbit, Atlantis would be slowed by its reaction control thrusters, and allowed to burn up over the Pacific.

  Libet could see the big delta-shaped wings, their leading edges battered by their multiple reentries, taken away from the orbiter hulk and stacked against a wall of the facility. Looking at the severed joint of each wing she could see their internal structure; the wings were just a skin of stiffened aluminum alloy over a framework of internal ribs and stringers. Detached from the orbiter, the wings looked crude, primitive. Something Howard Hughes might have recognized. The wings had been manufactured by Grumman, at their Bethpage plant in New York. Grumman had been the people who had manufactured the Lunar Module for Apollo. She wondered what the old-timers there thought of this day’s work.