Chapter 2

At one hundred twenty-eight seconds after launch, the acceleration suddenly dropped to zero. He breathed deeply again, and swallowed repeatedly to get the salty taste out of his throat. His stomach was uneasy, but he wasn't spacesick. Had he been prone to spacesickness, he would never have been accepted as a Rocket Interceptor pilot. Rocket Interceptor pilots had to be capable of taking all the punishment their ships could dish out.

He knew there would be fifty seconds of free-fall before the rockets fired again. One solid-fuel stage had imparted to the ship a velocity which would carry it to the altitude of the missile it was to intercept. A second solid-fuel stage would match trajectories with the missile. Final corrections would be made with the liquid-fuel rockets in the third stage. The third stage would then become a glider which eventually would carry him back to Earth.

Before the second stage was fired, however, the ship had to be oriented properly. The autopilot consulted its gyros, took some star sights, and asked the navigation computer some questions. The answers came back in seconds, an interval which was several hours shorter than a human pilot would have required. Using the answers, the autopilot started to swing the ship about, using small compressed-gas jets for the purpose. Finally, satisfied with the ship's orientation, the autopilot rested. It patiently awaited the moment, precisely calculated by the computer on the ground, when it would fire the second stage.

Major Harry Lightfoot, fighter pilot, waited idly for the next move of his ship. He could only fume inwardly. This was no way for an Apache warrior to ride into battle. What would his grandfather think of a steed which directed itself into battle and which could kill its rider, not by accident, but in its normal operation? He should be actively hunting for that missile, instead of lying here, strapped into his couch so he wouldn't hurt himself, while the ship did all the work.

As for the missile, it was far to the north and slightly above the ship. Without purpose of its own, but obedient to the laws of Mr. Newton and to the wishes of its makers, it came on inexorably. It was a sleek aluminum cylinder, glinting in the sunlight it had just recently entered. On one end was a rocket-motor, now silent but still warm with the memory of flaming gas that had poured forth from it only minutes ago. On the other end was a sleek aerodynamic shape, the product of thousands of hours of design work. It was designed to enter the atmosphere at meteoric speed, but without burning up. It was intended to survive the passage through the air and convey its contents intact to the ground. The contents might have been virulent bacteria or toxic gas, according to the intentions of its makers. Among its brothers elsewhere in the sky this morning, there were such noxious loads. This one, however, was carrying the complex mechanism of a hydrogen bomb. Its destination was an American city; its object to replace that city with an expanding cloud of star-hot gas.

* * * * *

Suddenly the sleek cylinder disappeared in a puff of smoke, which quickly dissipated in the surrounding vacuum. What had been a precisely-built rocket had been reduced, by carefully-placed charges of explosive, to a collection of chunks of metal. Some were plates from the skin and fuel tanks. Others were large lumps from the computer-banks, gyro platform, fuel pumps, and other more massive components. This was not wanton destruction, however. It was more careful planning by the same brains which had devised the missile itself. To a radar set on the ground near the target, each fragment was indistinguishable from the nose cone carrying the warhead. In fact, since the fragments were separating only very slowly, they never would appear as distinct objects. By the time the cloud of decoys entered the atmosphere, its more than two dozen members would appear to the finest radar available on the ground as a single echo twenty-five miles across. It would be a giant haystack in the sky, concealing the most deadly needle of all time. No ground-controlled intercept scheme had any hope of selecting the warhead from among that deceptive cloud and destroying it.

The cloud of fragments possessed the same trajectory as the missile originally had. At the rate it was overtaking RI 276, it would soon pass the ship by. The autopilot of RI 276 had no intention of letting this happen, of course. At the correct instant, stage two thundered into life, and Harry Lightfoot was again smashed back into his acceleration couch. Almost absentmindedly, the ship continued to minister to his needs. Its attention was focused on its mission. After a while, the ground computer sent some instructions to the ship. The navigation computer converted these into a direction, and pointed a radar antenna in that direction. The antenna sent forth a stream of questing pulses, which quickly returned, confirming the direction and distance to the oncoming cloud of missile fragments. A little while later, fuel pumps began to whine somewhere in the tail of the ship. Then the acceleration dropped to zero as the second-stage thrust was terminated. There was a series of thumps as explosive bolts released the second stage. The whine of the pumps dropped in pitch as fuel gushed through them, and acceleration returned in a rush. The acceleration lasted for a few seconds, tapered off quickly, and ended. A light winked on on the instrument panel as the ship announced its mission was accomplished.

Major Harry Lightfoot, fighter pilot, felt a glow of satisfaction as he saw the light come on. He might not have reflexes fast enough to pilot the ship up here; he might not be able to survive the climb to intercept without the help of a lot of fancy equipment; but he was still necessary. He saw still one step ahead of this complex robot which had carried him up here. It was his human judgment and his ability to react correctly in an unpredictable situation which were needed to locate the warhead from among the cluster of decoys and destroy it. This was a job no merely logical machine could do. When all was said and done, the only purpose for the existence of this magnificent machine was to put him where he was now; in the same trajectory as the missile, and slightly behind it.

Harry Lightfoot reached for a red-handled toggle switch at the top of the instrument panel, clicked it from AUTO to MANUAL, and changed his status from passenger to pilot. He had little enough time to work. He could not follow the missile down into the atmosphere; his ship would burn up. He must begin his pull-out at not less than two hundred miles altitude. That left him one hundred eighty-three seconds in which to locate and destroy the warhead. The screen in the center of his instrument panel could show a composite image of the space in front of his ship, based on data from a number of sensing elements and detectors. He switched on an infrared scanner. A collection of spots appeared on the screen, each spot indicating by its color the temperature of the object it represented. The infrared detector gave him no range information, of course. But if the autopilot had done its job well, the nearest fragment would be about ten miles away. Thus even if he set off the enemy warhead, he would be safe. At that range the ship would not suffer any structural damage from the heat, and he could be down on the ground and in a hospital before any radiation effects could become serious.

He reflected quickly on the possible temperature range of the missile components. The missile had been launched from Central Asia, at night, in January. There was no reason to suppose that the warhead had been temperature-controlled during the pre-launch countdown. Thus it probably was at the ambient temperature of the launch site. If it had been fired in the open, that might be as low as minus 70° F. Had it been fired from a shelter, that might be as high as 70° F. To leave a safety margin, he decided to reject only those objects outside the range plus or minus 100° F. There were two fragments at 500° F. He rejected these as probably fragments of the engine. Six more exhibited a temperature of near minus 320° F. These probably came from the liquid oxygen tanks. They could be rejected. That eliminated eight of the objects on the screen. He had nineteen to go. It would be a lot slower for the rest, too.

* * * * *

He switched on a radar transmitter. The screen blanked out almost completely. The missile had included a micro-wave transmitter, to act as a jammer. It must have been triggered on by his approach. It obviously hadn't been operating while the ship was maneuvering into position. Had it been transmitting then, the autopilot would simply have homed on it. He switched the radar to a different frequency. That didn't work. The screen was still blank, indicating that the jammer was sweeping in frequency. He next tried to synchronize his radar pulses with the jammer, in order to be looking when it was quiet. The enemy, anticipating him, had given the jammer a variable pulse repetition rate. He switched off the transmitter, and scanned the radar antenna manually. He slowly swung it back and forth, attempting to fix the direction of the jammer by finding the direction of maximum signal strength. He found that the enemy had anticipated him again, and the jammer's signal strength varied. However, he finally stopped the antenna, satisfied that he had it pointed at the jammer. The infrared detector confirmed that there was something in the direction the antenna pointed, but it appeared too small to be the warhead.

He then activated the manual piloting controls. He started the fuel pumps winding up, and swung the ship to point normal to the line-of-sight to the jammer. A quick blast from the rockets sent the image of the jammer moving sideways across the screen. But, of greater importance, two other objects moved across the screen faster than the jammer, indicating they were nearer the ship than was the jammer. He picked the one which appeared the nearest to him, and with a series of maneuvers and blasts from the rockets placed the object between himself and the jammer. He switched the radar on again. Some of the jammer signal was still leaking through, but the object, whatever it was, made an effective shield. The radar images were quite sharp and clear.

He glanced at the clock. Nullifying the jammer had cost him seventy-five seconds. He'd have to hurry, in order to make up for that time. The infrared detector showed two targets which the radar insisted weren't there. He shifted radar frequency. They still weren't there. He decided they were small fragments which didn't reflect much radar energy, and rejected them. He set the radar to a linearly polarized mode. Eight of the targets showed a definite amplitude modulation on the echo. That meant they were rotating slowly. He switched to circular polarization, to see if they presented a constant area to the radar beam. He compared the echoes for both modes of polarization. Five of the targets were skin fragments, spinning about an axis skewed with respect to the radar beam. These he rejected. Two more were structural spars. They couldn't conceal a warhead. He rejected them. After careful examination of the fine structure of the echo from the last object, he was able to classify it as a large irregular mass, probably a section of computer, waving some cables about. Its irregularity weighed against its containing the warhead. Even if it didn't burn up in the atmosphere, its trajectory would be too unpredictable.

He turned to the rest of the targets. Time was getting short. He extracted every conceivable bit of information out of what his detectors told him. He checked each fragment for resonant frequencies, getting an idea of the size and shape of each. He checked the radiated infrared spectrum. He checked the decrement of the reflected radar pulse. Each scrap of information was an indication about the identity of the fragments. With frequent glances at the clock, constantly reminding him of how rapidly his time was running out, he checked and cross-checked the data coming in to him. Fighting to keep his mind calm and his thoughts clear, he deduced, inferred, and decided. One fragment after another, he sorted, discarded, rejected, eliminated, excluded. Until the screen was empty.

Now what? Had the enemy camouflaged the warhead so that it looked like a section of the missile's skin? Not likely. Had he made a mistake in his identification of the fragments? Possibly, but there wasn't time to recheck every fragment. He decided that the most likely event was that the warhead was hidden by one of the other fragments. He swung the ship; headed it straight for the object shielding him from the jammer, which had turned out to be a section from the fuel tank. A short blast from the rockets sent him drifting toward the object. One image on the screen broadened; split in two. A hidden fragment emerged from behind one of the ones he had examined. He rejected it immediately. Its temperature was too low. He was almost upon the fragment shielding him from the jammer. If he turned to avoid it, the jammer would blank-out his radar again. He thought back to his first look at the cloud of fragments. There had been nothing between his shield and the jammer. The only remaining possibility, then, was that the warhead was being hidden from him by the jammer itself. He would have to look on the other side of the jammer, using the ship itself as a shield.

He swung out from behind the shielding fragment, and saw his radar images blotted out. He switched off the radar, and aimed the ship slightly to one side of the infrared image of the jammer. Another blast from the rockets sent him towards the jammer. Without range information from the radar, he would have to guess its distance by noting the rate at which it swept across the screen. The image of the jammer started to expand as he approached it. Then it became dumbbell shaped and split in two.

As he passed by the jammer, he switched the radar back on. That second image was something which had been hidden by the jammer. He looked around. No other new objects appeared on the screen. This had to be the warhead. He checked it anyway. Temperature was minus 40° F. A smile flickered on his lips as he caught the significance of the temperature. He hoped the launching crew had gotten their fingers frozen off while they were going through the countdown. The object showed no anomalous radar behavior. Beyond doubt, it was the warhead.

Then he noted the range. A mere thirteen hundred yards! His own missile carried a small atomic warhead. At that range it would present no danger to him. But what if it triggered the enemy warhead? He and the ship would be converted into vapor within microseconds. Even a partial, low-efficiency explosion might leave the ship so weakened that it could not stand the stresses of return through the atmosphere. Firing on the enemy warhead at this range was not much different from playing Russian Roulette with a fully-loaded revolver.

Could he move out of range of the explosion and then fire? No. There were only twelve seconds left before he had to start the pull-out. It would take him longer than that to get to a safe range, get into position, and fire. He'd be dead anyway, as the ship plunged into the atmosphere and burned up. And to pull out without firing would be saving his own life at the cost of the lives he was under oath to defend. That would be sheer cowardice.

* * * * *

He hesitated briefly, shrugged his shoulders as well as he could inside his flying suit, and snapped a switch on the instrument panel. A set of cross hairs sprang into existence on the screen. He gripped a small lever which projected up from his right armrest; curled his thumb over the firing button on top of it. Moving the lever, he caused the cross hairs to center on the warhead. He flicked the firing button, to tell the fire control system that _this_ was the target. A red light blinked on, informing him that the missile guidance system was tracking the indicated target.

He hesitated again. His body tautened against the straps holding it in the acceleration couch. His right arm became rigid; his fingers petrified. Then, with a convulsive twitch of his thumb, he closed the firing circuit. He stared at the screen, unable to tear his eyes from the streak of light that leaped away from his ship and toward the target. The missile reached the target, and there was a small flare of light. His radiation counter burped briefly. The target vanished from the radar, but the infrared detector insisted there was a nebulous fog of hot gas, shot through with a rain of molten droplets, where the target had been. That was all. He had destroyed the enemy warhead without setting it off. He stabbed the MISSION ACCOMPLISHED button, and flicked the red-handled toggle switch, resigning his status as pilot. Then he collapsed, nerveless, into the couch.

The autopilot returned to control. It signaled the Air Defense network that this hostile track was no longer dangerous. It received instructions about a safe corridor to return to the ground, where it would not be shot at. As soon as the air was thick enough for the control surfaces to bite, the autopilot steered into the safe corridor. It began the slow, tedious process of landing safely. The ground was still a long way down. The kinetic and potential energy of the ship, if instantly transformed into heat, was enough to flash the entire ship into vapor. This tremendous store of energy had to be dissipated without harm to the ship and its occupant.

Major Harry Lightfoot, fighter pilot, lay collapsed in his couch, exhibiting somewhat less ambition than a sack of meal. He relaxed to the gentle massage of his gee-suit. The oxygen control winked reassuringly at him as it maintained a steady flow. The cabin temperature soared, but he was aware of it only from a glance at a thermometer; the air conditioning in his suit automatically stepped up its pace to keep him comfortable. He reflected that this might not be so bad after all. Certainly none of his ancestors had ever had this comfortable a ride home from battle.

After a while, the ship had reduced its speed and altitude to reasonable values. The autopilot requested, and received, clearance to land at its preassigned base. It lined itself up with the runway, precisely followed the correct glide-path, and flared out just over the end of the runway. The smoothness of the touchdown was broken only by the jerk of the drag parachute popping open. The ship came to a halt near the other end of the runway. Harry Lightfoot disconnected himself from the ship and opened the hatch. Carefully avoiding contact with the still-hot metal skin of the ship, he jumped the short distance to the ground. The low purr of a motor behind him announced the arrival of a tractor to tow the ship off the runway.

"You'll have to ride the tractor back with me, sir. We're a bit short of transportation now."

"O.K., sergeant. Be careful hooking up. She's still hot."

"How was the flight, sir?"

"No sweat. She flies herself most of the time."

THE END