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His voice trailed off as the warning bells abruptly went off full force. The nosewheel was slightly closer to him!
"Bets, the shuttle's sliding backwards!" he shouted into the mike. "The collar must be slipping!"
For a few seconds all he could hear was the muffled, indistinct sound of frantic conversation. Eyes still glued to the slowly moving nosewheel, he jammed his earphone tighter against his ear. "Bets, did you copy? I said—"
"We copied," Paul Marinos's voice told him. "Betsy's getting the shuttle to boost its thrust. Stand by, okay?"
Pursing his lips tightly under his oxygen mask, Greenburg shifted his gaze back along the shuttle to its main passenger door. If the collar was slipping he should be able to see the door slowly sliding further and further beneath the huge ring.... He still hadn't decided if it was moving when Betsy's voice made him start.
"Aaron? Is the shuttle still moving?"
"Uh... I'm not sure. I don't think so, but all the vibration makes it hard to tell."
"Yeah." A short pause. "Aaron, Tom, you've both done some shuttle flying, haven't you? What are the chances Rayburn could bring this one down safely, damaged as it is?"
Something very cold slid down the center of Greenburg's back. Betsy knew the answer to that one already—they all did. The fact that she was asking at all implied things he wasn't sure he liked. Surely things weren't desperate enough yet to be grasping at that kind of straw... were they?
Lewis, after a short pause, gave the only answer there was. "Chances are poor to nonexistent—you know that, Betsy. He'd have to leave here at a speed of at least a hundred sixty-five knots, and with one or more windows gone in the cockpit he'd have an instant hurricane in there. He sure as hell won't be able to fly in that, and I personally wouldn't trust any autopilot that's gone through what his has."
"You can't slow down past a hundred sixty-five knots?" Whitney, the computer man, asked.
"That's our minimum flight speed," Lewis told him shortly.
"I know that. What I meant was whether you could try something like a stall or some other fancy maneuver that would pull your speed temporarily lower."
"Wouldn't gain us enough, I'm afraid," Betsy said, sounding thoughtful. "Besides which, wing sections aren't designed for fancy maneuvers." She seemed to sigh. "We've got a new problem, folks. The shuttle's backwards drift, Aaron, was not the collar slipping. It was the last two supports bending, apparently under slightly unequal thrusts from the shuttle's engines."
Lewis growled an obscenity Greenburg had never heard him use. "What happens if they break? Does the collar fall off the shuttle?"
"The book says yes—but exactly when it goes depends on how fast the hydraulic fluid drains out. My guess is it would hold on long enough to turn the shuttle nose down before dropping off and crashing somewhere in the greater Fort Worth area."
"Followed immediately by the shuttle," Greenburg growled. His next task was clear—too clear. "All right, say no more. Tom, there should be a supply locker just forward of here. See if there's any rope or cable in it, would you?"
"What do you want that for?" Betsy asked, her tone edging toward suspicious.
"A safety harness. I'm going to go inside the bay and see if there's any way to get that forward clamp co
"Yeah, there's some rope here. Just a second—I have to untangle it."
"Hold it, Tom," Betsy said. "Aaron, you're not going in there. You're a pilot, not a mechanic, remember? We'll wait for some professionals from the ground to handle this."
"Wait how long?" he shot back, apprehension putting snap into his tone. "Rayburn can't keep firing his engines all day; and even if he could you have no guarantee the thrusts from all three turbofans would stay properly balanced. Do you?"
There was a short silence, during which Greenburg was startled by something snaking abruptly across his chest. It was Lewis, perhaps sensing the outcome of the argument, starting to tie Greenburg's safety line around him. "No," Betsy finally answered his question. "Rayburn's on-board can't give us those numbers any more, and the support stress indicators aren't really sensitive enough."
"Which means chances are good the shuttle's going to continue putting stresses on the clamps—variable stresses, yet. They're bound to fatigue eventually under that kind of treatment."
"Mr. Greenburg—Aaron—look, the program's almost finished ru
"No; only once we've found the problem and made sure the other wing sections don't have it. Who knows how long that'll take?" A tug on the rope coming off the chest of the makeshift harness Lewis had tied around him and a slap on the back told him it was time. Gripping the edges of the opening, he raised a foot, seeking purchase on the curved wall. Lewis's cupped hands caught the foot, steadied it. Greenburg started to shift his weight... and paused. He was still, after all, under Betsy's authority. "Bets? Do I have permission to go?"
"All right. But listen: you've got one shot at the clamp, and whether it reaches or not you're coming straight out afterward. Understand? No one's ever been in a docking bay during flight before, and you're not equipped for unexpected problems."
"Gotcha. Here goes."
Greenburg had spent the past couple of minutes studying the curving bay wall, pla
He didn't slide far; Lewis, belaying the line, made sure of that. Getting his legs back around underneath him, Greenburg checked his footing and nodded back toward the opening. "Okay, I'm essentially down. Let me have some slack." Moving carefully, he stepped down into the teardrop-shaped well under the shuttle and walked to the nosewheel.
The forward clamp was designed to slide out of the wall as the landing gear was lowered, locating the tow bar by means of two short-range transponders installed in the gear. Earlier, up on the flight deck, Greenburg had confirmed the clamp operation had been begun but not completed; now, on closer study, the problem looked like it might be obvious.
"The shuttle's not only angled into the bay wrong, but it's also rotated a few degrees on its axis," he reported to the others. "I think maybe that the clamp's wrist rotated as far as it could to try and match, and when it couldn't get lined up apparently decided to quit and wait for instructions."
"The telltales say it is fully extended, though," Henson insisted.
"Well... maybe it's the sensors that got scrambled."
"Assume you're right," Betsy said. "Any way to fix it?"
"I don't know." Greenburg studied the clamp and landing gear, acutely aware of the vibrating shuttle above him—and of the vast distances beyond it. But even if the shuttle fell out and my rope broke I'd be all right, he told himself firmly. Standing in the cutout well that gave the shuttle's nosewheel room to descend, he was a good two meters below the rim of the bay's outer opening. There was a fair amount of eddy-generated wind turbulence plucking at his jumpsuit and adding a wind-chill to the frigid air—but it would take a lot of turbulence to force him up that slope and out. At least, he thought so.... "Why don't you try backing the clamp arm up and letting it take another run at the tow bar?"