Silver Tower

by Dale Brown

  Govorov's earlier mood quickly melted away. "Do you think the late takeoff is significant?"

  Gulaev shrugged. "The most important, the most widely publicized space flight by the outraged Americans, and it takes off ninety minutes late.... It could be, sit. "

  Govorov nodded,. went quickly to a computer-monitor at the extreme right end of the master command console, moving a technician aside as he scrolled through the display. "These tracking data are hours old," Govorov said. Gulaev moved to his side and noticed that his superior was checking the orbital status readouts of the space station Armstrong. "We can update th data in three hours," Gulaev told him, checking the chronometer again. "But the station's orbit is erratic and its altitude is decreasing rapidly. It's becoming harder and harder to track. I I -

  Govorov studied the information. Armstrong was, miraculously, still in one piece, judging by the signal strength of the radars tracking the station. It seemed they would need to

  redefine what they considered the upper limits of the atmosphere. One hundred

  thirty kilometers was thi usual altitude where atmospheric heating due to friction should cause damage to a spacecraft, but it was also generally acknowledged that the upper Atmosphere was not flat like a desert but as craggy as the Himalayas: in some spots it only extended to eighty kilometers, in others perhaps a hundred fifty. Earth's atmosphere, as Govorov had observed many times from space, was like a boiling cauldron. Clouds revealed only a small fraction of the real turbulence in the sky. Surely the American space station should have impacted with enough of the higher peaks of the atmosphere to cause some damage. Apparently, it had not . . . ?

  A vague sense of unease began to grip Govorov as he recalled his words to Colonel Voloshin-something about the space station Armstrong remaining a threat as long as it was in orbit. For the past few weeks he had allowed himself the luxury of thinking the station was doomed, that his two-ship attack force had inflicted a mortal blow. But the station was

  still aloft. Was it also still a danger?

  Logic said no. The station was mere hours from reentering the atmosphere. The crew of the spaceplane America had little time to retrieve the bodies of their dead crewmembers, let alone boost the station into higher orbit. Their late takeoff was like a death sentence for the station. No, he had accomplished his mission. . . . The station was just taking a little longer to expire.

  He took a deep breath, nodded to Gulaev. "Be sure careful records are made of the spaceplane's progress. I will be in quarters. "

  A few more hours, Govorov thought as he left the command center for his waiting vehicle. Just a few more hours. . . .

  HYPERSONIC SPACEPLANE AMERICA

  It was long, long after America had reached orbit that Ann was able to recover fully from the sheer excitement of the launch. Marty Schultz almost had to shake her to get her attention. "We're in orbit," Marty said. "Sorry to startle you but I haven't seen you move in a few minutes." "I feel drained, like I just ran a marathon." "Well, it's not your usual shuttle launch, for sure."

  That, Ann decided, was a rank understatement. Unlike the shuttle, which gradually climbed into orbit, the spaceplane America sprinted into orbit. From the moment the rocket engines were ignited on the sled that propelled the spaceplane down the long launch track in the high southern California desert, she had felt the crushing "g"-forces pin her body to her seat. America had been boosted from zero to two hundred miles per hour in less than fifteen seconds . . . It was nearly impossible to believe that seven hundred thousand pounds of machine could be accelerated at such a rate.

  She'd thought the "g"s would diminish after they'd lifted off the rocket sled, but they hadn't even begun to slacken. The first indication of a force even greater than the rockets on the sled came when the center scrainjet engine ignited. The three-hundred-fifty-ton spaceplane bucked like a living thing, lurching so hard that the hydraulic "g"-dainpeners in Ann's seat could hardly absorb the shock. One hundred miles an hour of airspeed was added to the forward momentum of the spaceplane in the blink of an eye. Her "g"-suit had immediately inflated to keep her from blacking out, and if her face mask had not shot oxygen under pressure into her lungs she would have suffocated. As it was, her rib cage felt heavy as lead and breathing was suddenly impossible. When the other two scrainjet engines ignited shortly afterward, her "g--dampening seat had hit its limit and her body was forced to endure the ever-building, crushing pressure. She had had to perform an "H-maneuver," whereby blood was forced to the upper body and head by partially closing off the trachea, and then grunting against the pressure. She glanced sideways

  during the ascent and saw Horvath's chest heave and flutter as

  he performed the maneuver too.

  By the time all three scrairjet engines were numing, America was traveling at well over three hundred miles per hour and had already streaked down three of the five miles of launch track. The restraining clamps were then released, and the spaceplane lifted off the sled and shot skyward. If the three engines

  hadn't ignited, high-pressure steam jets on the last mile of the track would have automatically activated and begun slowing the spaceplane down below two hundred miles an hour, where arresting cables and hydraulic brakes could be applied.

  As it was, America broke the sound barrier twenty seconds after lifting off from the takeoff sled. She was then pulled up into a forty-five-degree climb at six "g"s, racing skyward at over fifty thousand feet per minute. The craft went hypersonicpast the Mach five mark-fifty seconds later as it passed forty thousand feet altitude, the ear-shattering sonic boom rattling across the Sierra Nevada mountains far below. By the time America reached the Canadian border five minutes later it was

  at Mach fifteen, still climbing on top of a column of hydrogen fire nearly a mile long. Her wings were retracted at that point because at two hundred thousand feet altitude there was not enough air to generate lift.

  The louvers at the front of the scranijets; engines automatically closed as the spaceplane climbed, so five minutes into the flight the aim-aft had transformed itself into a liquidfueled rocket. As the engine began to bum more pure internal liquid oxygen, the speed increased. Finally, ten minutes into the flight the crushing "g" forces began to subside as America completed its acceleration to orbital velocity.

  Now several banks of orbital maneuvering jets were activated to begin matching America's orbit with that of the stricken space station. The climb to Silver Tower's altitude didn't take long: on the lowest part of its orbit the station was now down to only five hundred thousand feet-eighty-three miles-altitude, low enough to be clearly visible to observers on earth. Following tracking and steering signals provided by groundbased tracking stations-Armstrong had stopped transmitting a position and docking beacon weeks earlier--Saint-

  Michael and Hampton began to chase down the stricken space station. "Digital autopilot slaved to Ku-band tracking signals," Hampton reported. "Mimic is estimating thirty minutes to rendezvous. " . Saint-Michael was studying America's flight-profile readouts and environmental displays. "Eighty miles," he muttered. "We're barely above entry interface altitude"-where the spacecraft began to enter earth's atmosphere and decelerate on account of friction. "Check the radiator and coolant f"ss-flow. It's already midway in the caution range. " "Coolant flow is maximum," Hampton said, checking another screen. "We can try partially closing the radiators to cut down on the friction. Or we can go to EMER on the cross-flow system to bring the temperature down to the normal range. I I

  "How about that fuel back there?" Saint-Michael said. "We can't play around so close to the atmosphere like this. We may have to jettison the fuel in the tank when coolant temperature reaches the danger level. There's no sense holding onto it longer and endangering the ship." "Can you power up the station or reposition it without a refueling?" "I don't know. I don't remember how bad the solar panels

  the station were hit." Like Ann, Horvath and Schultz, Saint-Michael had kept his POS facemask on to continue prebreathing pur
e oxygen in preparation for their spacewalk into the station. As he spoke, hebegan massaging his temples. "You all right, General?" Hampton asked.

  Saint-Michael quickly lowered his hands from his head. "Sorry, bad habit. Just thinking, believe it or not.... That Russian spaceplane attack knocked out power in the command module, but I think the SBR and Skybolt were sifill running when I found Ann unconscious in the Skybolt control module. That may mean that the station is still functioning, at least partially." "But Falcon Control lost the station's ID and TDRS tracking signal weeks ago. They've assumed all power is out." "We'll assume the same." Saint-Michael pressed the but-

  ton on his comin link. "Listen up, crew. We won't have much time, and we've got to assume that the station is completely dead. Our priority will be to boost the station to a safe altitude. After that we'll try to power her up, reposition her, set up SBR surveillance of the Indian Ocean and the Nimitz carrier group in the Arabian Sea and begin to make some structural repairs. In between we'll probably have to fight off another attack. . . . Ann, you'll

  be in charge o setting up the PAM boosters on the.keel. I know Marty's explained how and where they go. Any questions?" "No," Ann said, still finding it hard to believe they were going to reactivate the station after all. "It's a lot simpler than disconnecting Skybolt would have been." "Good. Marty, you'll be in charge of refueling the cells on the keel so we can get electric power back on. The cargo shovel appeared damaged'so you'll have to do it the hard way: drag the fuel tank around to the cells with the MMU maneuvering unit and use the remote fuel-transfer system. Any problems with that?" "I used to pump gas in Ohio when I was nine years old." "Just be ready in case Ann needs help." "Rog. I I

  "Ken, you'll follow me into the station," he told Horvath. "The environmental and electrical controls are easier to work than a shuttle is, so you shouldn't have too much problem figuring them out. We'll try to get solar power on, followed by fuel-cell power. If you can find and patch up any holes in the command module, it'll make our work easier. Otherwise we'll just try to reactivate the station's attitude and environmental system.... Jon, you take care of America and try to help anyone out that needs help. The PAM installation has priority. After that, refueling and repairs. Keep us advised of any messages from Falcon Control until we get communications going on Silver Tower." "Right. "

  Thirty minutes later, they had moved to within a few hundred yards of Silver Tower.

  For a few long moments the sight of the station in the distance dampened everyone's enthusiasm.... The damage was worse than any of them had imagined...

  The station's spin had decreased in velocity but it was gyrating on at least three or four different axes at once, like some sort of unearthly multilegged monster with dozens of different appendages reaching out to grab the spaceplane and devour it. Ionization from frequent scrapes with earth's upper atmosphere had created a multicolored, undulating aura of energy around the station. Parts of the central open-lattice keel glowed like hot embers, and clouds of debris and frozen water, gases, and fuel hovered everywhere. Several large panels from the SBR airays and solar collectors were missing or damaged.

  Hampton looked uneasily at Saint-Michael. "Do you think it's safe to approach the station with all that junk and sparking out there?" "No. But we've got to do it." ,'Sir, wait." Hampton turned in his seat to face SaintMichael. "'Me 'ifs' are really starting to pile up here. We'll be driving right into the middle of all that debris and heat ionization. Then we've got to try to match the moves the station is making.... One mistake ark we've got another dead ship." "You knew the risks, Jon. We all did. .

  Hampton paused, considered. Finally he shrugged and said, "Okay, General. We'll do it your way. Let's stick our noses into that beehive."

  Saint-Michael nodded, wrapped a hand around the manual control stick. "Here we go ......

  He had applied forward thrust for exactly two-point-one seconds when a terrific bang shook America from bow to stem. He glanced toward Hampton as they checked the computer monitors for damage indications. "Pretty big bees," Hampton said.

  Saint-Michael, ignoring him, took a tighter grip on the control stick and nudged it forward into the swirling mass ahead.

  America provided no visibility out the cockpit windows except for the commander and pilot, so the others were spared seeing the source. of the explosions, rumbles and flashes of

  light and heat that threatened to tear their ship apart during the final docking with Silver Tower.

  The cargo bay temperature had risen to the danger zone when they moved only two hundred yards closer to the crippled station. "Cargo bay overtemp warning," Hampton reported.

  Saint-Michael promptly overrode the preprogrammed cornmand-which had been to jettison the fuel tank-and chose "EMERGENCY COOLANT SHUNT" instead, opening

  a manifold from the scramjet intake coolant system that allowed supercooled hydrogen to flow from America's fuel tanks through to the radiators. It was a risky choice--the tiniest leak in the radiators would have allowed the hydrogen to be ignited by the superheated ionized particles streaming past the spaceplane from the station-but there was no explosion and the temperature moved away from the danger zone.

  Saint-Michael's fingers moved over the control buttons on the stick, switching between translate--straight-line--and rotate thrusts. Because it took less time to rotate in one direction than it did to reverse directions, America literally corkscrewed its way toward the docking port. They had been forced to hit smaller pieces of debris to avoid impact with larger ones. Debris breaking off or exploding from the station didn't always "fall" or disappear: it seemed to hang around the, station in a dangerous orbit of its own.

  After nerly thirty minutes America was hovering a mere ten feet from the docking adapter, held in place by the spaceplane's intricate station-keeping computers. But ten feet was still ten feet too much. "We can't go any further, General," Colonel Hampton said. "We've got the stationkeeping routine running as precise as the system allows."

  Horvath spoke up. "I'll go to the docking module and-- "No. I'll go," Saint-Michael said. "I 'd advise against it, General," Hampton said. "Your dysbarism ...... "I've got to do it sooner or later, Jon, and I'm the best qualified to check out the station. I've been prebreathing oxygen for the whole flight so I should be okay. You've got the ship." Saint-Michael waited until Hampton had adjusted

  his manual controls and situated himself, then unstrapped and floated back toward the airlock.

  Ann reached out and stopped him. "If you feel ... if you get in any trouble, get back."

  He nodded, moved past her. It took him five minutes to get into a spacesuit and backpack. Ann prepared to suit up after he exited the airlock, was watching him through the observation port on the chamber door as he began to depressurize the airlock. Suddenly, just as he moved the AIRLOCK DEPRESS switch from position five to zero, he quickly punched it back to five. "Jason?"

  He held up a hand toward her but seemed to be shaking his head trying to clear his vision. "Switch back to PRESSURIZE,- she called to him. "I'm all right." Saint-Michael slowly stood erect, shaking his head as if recovering from a fall. "It's gone He reached for the depressurization control again-- "No," Marty said quickly. "You can't do it, General-- "I'm all right." He waited a few moments, then switched the depressurization knob to zero. A few minutes later he gave Ann and Marty a thumbs-up and undogged the upper airlock hatch. Ann was repressurizing the airlock as soon as the general had locked the hatch after exiting. "Bad news," Saint-Michael said over his comm link. "The docking tunnel is unusabl"e whole docking module is about ready to break off the station. Everyone has to EVA."

  Saint-Michael scanned the spaceplane. The view of America against the chaos around the station was quite a sight.... The gray-black spaceplane seemed to add a sense of power and strength to the damaged station it hovered near. He could see tiny puffs of gas escaping from the maneuvering jets on America's nose and tail as the spaceplane maintained its tenuous position beside the station.
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  The scene looked normal if he concentrated on just the station and the spaceplane, but when he tried to look at earth the view became chaos again.

  With America in near-perfect synchronization with the station, there was no apparent movement between them-but earth appeared to be spinning all around them, making one

  revolution over Saint-Michael's head every minute. At first it was disorienting and he had to fight off the "leans"-his eyes telling him he was standing still, his head and body spinning and oscillating in reference to earth. It was like being on a crazy roller coaster with one's eyes closed. "Be careful

  when you step outside--the ride out here is a wild one. I don't see any major damage to America. Ann, I'm going to start unstowing the PAM boosters. I'll attach one, you get the other." "Roger. I'm a minute from EVA."

  Saint-Michael made his way carefully along America's spine toward the open cargo bay, his attention continually drawn to the damage on the station. The most serious was on the keel, especially- the SBR antennas. "7[be Russians did a job on the SBR control-junction boxes," he said. "It looks like we'll have to splice all of them but I can't be sure at this distance. One or two of the arrays might be intact."

  He continued down to the cargo bay and maneuvered beside one of the PAM booster engines, removed restraining pins on the cargo bay attach-points. "Both PAMs are unpinned.- "Copy, General," Marty Schultz said. Saint-Michael looked up as America's remote manipulator arm rose out of its launch stowage cradle and the tiny closed-circuit TV camera aimed itself at him. "Ready to eject the aft PAM."

  The general maneuvered back a few feet away from the booster. "Go." With a puff of gas the large booster slid out of its attachment sleeve and lifted slowly out of the cargo bay. As it rose up before him Saint-Michael maneuvered himself up and across to a reinforced mounting bracket on the side of the booster, then jetted forward until he could grasp the booster. He pulled himself into the booster and latched the front of his MMU to the bracket. His head was just above the top of the booster. "I've got the first PAM," he said. "Ann, I'm heading along the keel toward the spaceplanes' nose to attach the booster. You take yours toward America's tail to the keel. Mount your PAM perpendicular to America's alignment to the keel; I'll mount mine parallel to America. Maybe