SINGER COULDNT IDENTIFY the whine that reminded him of one of those trendy syntharmonic-muzac orchestras on Case IV as it tuned up without achieving sync. Sure, the escape pod had taken a little damage but it was a chunky robust vessel designed to fight its way through the debris of a disintegrating space Digger before a steady course could be plotted.

The radio didn't help. A gargle of warbled hisses filled his headphones through the worrying whistle. Fiddling with the tuner made it worse, so he had to be content with the automatic beacon that should've started broadcasting his emergency status.

THE DIGGER, a grey bulk, bristled with all the accoutrements necessary for asteroid mining. The only elegance was the search and identify probe: the nose, sniffing out the copper-red nickeline needed back home.

He cursed the moment that the probe had detected that flying mountain of platinum-laced iridium. As big as a small moon and a hundred lengths of the Digger across, the asteroid consisted entirely of impact craters.

Singer had not met anything like it; the metallic honey pot of the century hiding in a large cluster of asteroids. Asteroids are normally far apart but this had grouped, maybe already gathered by another enterprise, so he’d better be quick.  His computer calculated a rendezvous so he’d be alongside the swarm and matching their speed of five clicks per second.

He was too far from home to ask for advice; communications were sent by radio pulses in batches every eight days. Unless he was under attack, he was not to attempt communication with his masters.

While the computer considered the optimum strategy for the company to profit by the lump of iridium, Singer opted to land on the asteroid to grab a sample. He preferred to examine specimens in his lab than look at them through a telescope and remote-Kl4-spectrometer.

He’d have to justify his actions when he debriefed on return, but his whole employee existence was to bring home the goodies. He was treated like a company component spiced with stochastic improbabilities.

If anything went wrong the ship would return home. To the considerable embarrassment of some pilots, a glitch in the workings had occasionally convinced the computerised error-finder that it ought to send the ship back to base with a protesting, swearing but impotent passenger.

He used the navigational computer to inch the Digger closer to the asteroid. A landing would achieve two things; there was something distinctly fishy about such a large lump of high quality iridium floating around just for the taking and it gave him a chance to go for a stretch, albeit in a pressure suit.

The asteroid wasn't easy to approach. Other rocks littered the area. It was like doing a slow egg and spoon race in a 3-D maze with beach balls.

Singer hunched over the computer screen rather than watching the real view through the port. The screen showed multi-directional vectors, distance to touch, and ETA. It was a miracle that such a cumbersome Digger could be manoeuvred so deftly. It would be unlikely that a non-machine could make so many decisions on the basis of so many variables. Singer wouldn’t like to try. One of his qualities was an instinct for survival, which in his case was to duck out of bar-fights, let machines take all the risks and only go out with girls smaller than him.

His smile broadened in anticipation of a country hike as the ship settled on its hydraulic ramps and the retros died. He stood, stretched his arms and peered outside. Light from the distant sun barely illuminated the asteroid's surface. He adjusted the crystallised filter system in the view-port, switched on the outside lights and gaped. He wasn’t prepared for the rugged beauty of this little world. The steady dots of light from distant stars disappeared and reappeared as the asteroid swarm swept along. He couldn’t wait to get into his suit.

The computer must have noticed something Singer didn't and blinked at him. There was a shift in the asteroid’s motion relative to some of the space regolith around them. Although each lump was an entity in itself, happily travelling along its own flight path, you can't have so many so close together without side effects. Gravity fields, Van der Waal and other forces held the space debris. Newton's First Law had each moving meteorite travelling in a 'straight' line–gravity fields notwithstanding, unless some other force impinged. Singer's Digger impinged. It had gatecrashed on a four-billion-year-old party.

He’d added impetus where none had been before. Mass and velocity were the crackers and wine brought by this interloper.

Nothing dramatic was happening. Singer took risks, and so he buckled, checked, fastened, checked, zipped, checked, and left the computers to monitor the subtle changes.

A few minutes later he was outside, standing on the mineral-asteroid. Standing is an exaggeration; a hiccup would have given him escape velocity and sent him on his way to another rock. Consequently, he was attached by a life-line as if he was about to do a space-walk, instead of an asteroid hop. He was careful not to move fast but soon rediscovered the skills of toe-skipping, covering ten metres at a time.

He became overconfident and tripped. Sailing backwards through the non-air was another experience. He knew he couldn't be hurt but it still tightened his stomach. He landed on his back, several times. Eventually as he was still, lying there, the sky gripped him.

No photograph could've done justice to the vision. Apart from the thousands of stars in the distance, the asteroids looked as if they would tumble down on him any moment. The distant sun was just below his horizon but illuminated sharply broken rocks that hung over his head. He made out some colours: coppers and metallic blues but mostly a near-black ochre. It was difficult to believe that they were all moving at over five kilometres per second.

Having made the reckless decision to land, Singer had pre-determined routines to follow. He took samples of surface dust and augured cores. Gas chromatodetecter devices had to be planted along with a claim plaque bearing the company's registration in view of the ship's broad-scan laser image recorder. His suit thermistor told him the outside temperature was -170 increasing as the metal intercepted the sun's rays and turned the cold ultra-violet into infra-red. He knew that in the absence of an atmosphere the temperature should've been nearer to absolute zero. He smiled; he liked conundrums. Could this lump have an internal heat source? His smile turned down when he thought that the iridium might have more radioactive thorium than estimated. His brain pirouetted to the conclusion that he should return to the Digger.

On his way back, he tripped as his helmet bleeped into life. An emergency return to ship call! He cursed his clumsiness as he spent five minutes returning to the airlock. His face hot enough to boil an egg, he sat at the shiny console but to find one light blinking red. He smiled when he saw the emergency only related to navigation. Relaxed, he settled into his swivel chair and asked the computer to tell him the worst.

"Collision in eighty-eight point five-three hours."

"Eh?  What's going to hit us way out here?"

"This asteroid will be impacted by another asteroid," the computer had a warm feminine voice but its message was chilling.

"How far away is it?" Singer's brain was racing. He couldn't leave without taking at least enough of this asteroid to set him up for life.

"The intercepting asteroid is a hundred-and-eighty kilometres away travelling on a near parallel course but closing at point six four metres per second."

"Just over half a metre per second! You can't call that a collision. How big is it?"

"Two and a half kilometres diameter."

In desperation to save his retirement wealth, Singer quizzed the computer about the chances that the incoming asteroid might miss. No. On request, the computer summarised the unusual facts.

"Collision predicted is of the category known as a Slow Crash. Depending on the geological structure of both asteroids, the impact has an eighty-three percent probability of causing disintegrating fractures of both. Roche Limits don’t apply. The slow speed will not lessen the impact since the masses of the asteroids are so great. Enough to disintegrate the planet."

"Just a minute. Some of your connections must have oxidised. Surely a slow crash is impossible. As soon as any two masses get close enough their combined gravitational pull would accelerate them into a frenzied smash-up. It's not possible for two asteroid-sized lumps to gently touch." He was mischievously delighted to put one over on the computer. The exhilaration didn't last long.

"You are correct for a two particle problem. However..." Singer groaned as the computer gave him a lecture on the complications of multiple particle gravitational fields, the added effects of electro-magnetic fields and the influence of the electrical field from a nearby giant gas planet. It added up to the result that it was possible, however improbable, for a collection of debris to be in dynamic equilibrium. It was also feasible for a slight perturbation of the fields to edge some of the particles into closer proximity, the acceleration between two being offset by others around them.

Singer felt cheated and morose but after a long drink and think, asked the inevitable question. "Right, let's see. How much time have we to salvage what we can before we have to get away?"

"If the Digger left the asteroid in eighty-seven-point two hours we should be able to escape any detritus from the collision."

"Right, so we have until then to grab ourselves the juiciest chunks and get them out with the rest of our haul in tow."

Singer made himself a meal while deciding how to make a rapid survey of the asteroid when he felt an urge to see the incoming asteroid for himself. Seconds later, a crowded sky filled the screen. Cross-hairs targeted the approaching asteroid as a pale spot. Nothing seemed to move even that splodge inching its way closer.

Before he took off, he was going to salvage what he could. It needn't be a total write-off: after all, the projected collision might do him a favour by fragmenting the asteroid into more manageable chunks.

He tried to recall what he knew of slow crashes but couldn't. The computer library wasn't much help either. Did a slow crash create an explosive impact so the heat of even a slow contact, from friction or fusion gas ignition or radiation, would send projectiles at great speeds in random directions? How far should he stand off to be a safe observer? Might the two asteroids fuse together and go into a dumbbell spin?

He explored the rock and during the next twelve hours was able to retrieve some pleasing samples and store them in the hold. Several times while he was floating around on the surface he looked up at the incomer and at his other neighbours. He could never get used to admiring the firmament. Even the silent blackness in between the steady stars drew him.

He ought to give himself a wide margin of error and put distance between himself and the coming rendezvous. He sat at the console and initiated the take off procedure.

Nothing.

Singer stared unbelieving at the machine as it politely informed him take off was not possible.

"Why not?"

The sultry feminine voice said, "Evidence from back-interpolation indicates it was our presence that caused unpredicted perturbations in the localised magnetic and gravity fields to initiate the imminent collision."

"So? Let's get out of here. Make some more perturbations. Oh, I get it there's a directive saying I'm not to disturb planetary motions.” Singer was exasperated.

“Analysis reveals that taking off would cause at least three more collisions to occur. I'm programmed to prevent a worsening of the situation."

"But only from the point of view of the asteroids, not mine!"

The console remained silent. It obviously regarded the last statement as rhetorical. Singer tried another approach to change the computer's mind while his stomach warned him of imminent panic.

"What could change your decision?"

"A direct order from base is the only way to override my probability decisions."

"Doesn't the life of your pilot get any consideration in your metal conscience?"

"Only in as far as it does not interfere with the prime directives. It is imperative not to disrupt planetary motions."

Singer thought through this and tried again as if he was cross-examining a witness for the prosecution. "Is the incoming asteroid big enough to be a planet?"

"The asteroid is within the category of a small planetoid."

"Ah! Got you!" Singer raised his voice. "Why have you been helping me to take this 'planet' to pieces if you have a directive not to damage it?"

"That is not my programmed directive. Taking parts of any planet does not significantly affect its path of motion, but moving about in this unusually dense collection of small planetoids and asteroids is."

Singer was speechless. He stood and poured himself a stronger than recommended liquid stimulant while his mind grappled with the situation. He dug out the technical files that were in book form so the computer couldn't tell he was investigating the possibility of taking the ship over on manual. It was another blind. He could turn off the computer but not without disabling the ship, stranding him. The system was fail-safed to prevent a pilot from sabotaging or hijacking his own vessel.

The next few days were torturous. He went for walks and gazed up to seek some inner peace with himself, to accept his fate, take what was coming, and to think of a set of words that might unlock the computer.

The threatening asteroid increased in size as he gazed at it. His hated executioner. He stared until his eyes watered. In desperation, he sat heavily on the stool in front of the console and tried everything again for the fifth time.

No.

Out of interest he asked the computer if any other asteroids were displaced by their presence.

"Six discernible bodies are moving along routes that are not on the same course they were. Many smaller meteorites are also on impact courses with other bodies besides this one."

"Ah, so even if we sat here until impact, there are other changes in the equilibrium of the swarm that could create greater havoc than if we took off?"

"That is possible. It would be necessary to compute the trajectories of each body, identify their impact targets, assess the individual probabilities of either disintegration or ricochet deflection and compute the resonance or secondary flight paths that resulted. At each impact, the certainty of forecasting the flight paths and hence the stability of the total swarm reduces by thirty-six percent with a confidence limit of—"

"Wait. Can you compute the effects of our take-off in the same way?"

"Yes but the probabilities of assessing the secondary impacts remain the same."

"So, the future of the stability of this swarm is equally indeterminate whether or not we take off."

"Affirmed." The computer voice synthesiser hardly seemed to pause between its answers in contrast to Singer's agonised synapse-wringing deliberations.

After a deep breath, Singer launched into what he hoped would be the clincher. "In that case, my intelligent friend, since the outcome of our take-off cannot be proven to make the matter worse, we might as well leave and save our skin. After all, if we stay, not only will a collision take place but we'd be obliterated and our flight through the swarm can't be proved to make matters worse. Whereas if we stay, the results of the collision might be just as disruptive if not worse.” He sucked in air, whistling through clenched teeth as he awaited the rebuttal.

"Affirmed"

Singer was stunned. Had the computer, which had used its logic to deny him his escape, changed its mind after a to-and-fro with a mere mortal?

"You agree with me and we can leave?"

"Affirmative and negative. There is no doubt that the determination of future collisions is equally inexact but our take-off might worsen the situation and so the prime-directive is unchanged."

In exasperation, Singer shouted at the console, "So it's not enough to show our take-off can't make matters worse, we have to prove our leaving would improve the situation?"

"Agreed." the terseness of the voice synthesiser could be irritating but part of the pilot's training was not only to get used to it but to appreciate such efficiency. However, in this situation, Singer had to think aloud while the computer just outputted the results of its reasoning.

Singer rubbed his forehead to placate an incipient headache. "Is there any way we could ensure our take-off would reduce the damage? For instance. could we use our rockets or our industrial explosives to push this asteroid out of the way or to minimise the impact?"

"No, the effect would be negligible. Our resources are for gathering small meteorites with the occasional larger lumps to take in tow."

Singer thrashed around for ideas knowing that failure meant annihilation.

He turned again to watch the incoming killer, now able to make out features on its surface; jagged craters, striations, and ray-streaks. Breathing heavily he muttered. "Come on, you suggest something..."

"With respect to what?"

"With respect to us getting off this hunk of scrap metal before we're turned into part of it." He wondered at machine intelligence. "In other words, if you were in my position what would you do?"

"I suggest you use manual controls. This can be done by—"

Singer wasn't listening; he was in shock. He couldn't believe what he just heard.

"But... why didn't you tell me this before?"

"You didn't ask."

If a computer could be smug, this one was and enjoying it.

Another thought wormed its way.

"Does this suggestion of yours mean you’d allow me to manually take off?" This wasn't quite a rhetorical question. Singer lost his trust in the computer as an adviser. Its logic reneged on the pilot’s survival.

"I can permit your take-off but I cannot assist it."

Singer sipped a cold tea. "Maybe I shouldn’t enquire but why allow me to use unassisted manual controls to take off?"

"Your assumption of control Code 872/a19 under the circumstance of an emergency as in Code 192/16f abrogates my responsibilities."

"Yes, I'm sorry I asked,” he said. He’d been building up to the next question. “How much time do I have before lift-off would be a waste of time anyway?"

"No time. There is nil probability of your successful passage through the swarm unaided by my navigation system."

Singer was thoroughly confused now. The computer seemed to be contradicting itself.

"Then why did you recommend I should take off using manual controls when there's no chance of making it?"

"You asked me what I would do in your place not what I would do if I were you. I have a superior intellect, faster responses and greater sensory receptivity than you."

"But with my brain-box it would be impossible. I get it. Thanks a lot."

He thought about the last exchange. In spite of his frustration he knew the computer was right. However, in spite of the odds against him he’d have to try. After all, the company included a non-mechanical operant for just this type of beyond-the-odds event. He’d mistakenly assumed that since the computer won’t take off then it wouldn’t allow him access to the controls.

SINGER HAD SIMULATED unassisted lift-offs. They were difficult. You needed twenty-one fingers and all the skills of several video-game champions rolled into one.

With only three hours to spare, he punched up the procedures. He stopped reading when he forgot the first page initiation procedures. He glanced at his countdown clock and sipped a stimulant.

The ship would still have its remote control switches usable but he’d have to operate them from a console instead of the computer making decisions. The ship would automatically use its gyroscopic balance controls, other equilibrium feedback systems would work including the life-support-system and impending impact warnings would deafen him.

Just before he touch-started the sequence that would effectively turn the computer off, he turned on his favourite music, a haunting syncopated melody: repetitive but comforting. If he was going to go, he might as well go in style.

It took him longer than expected to do all the pre-flight checks but eventually the large Digger left the surface. He adjusted the rumbling thrust in five rockets simultaneously. There was danger in the acceleration considering the low gravity field he was in. He didn't want to shoot off into the meteor swarm too fast to be able to control his ungainly vehicle. Luckily, the incoming asteroid was coming from behind him as he took off but, even so, he worried. The time of impact was in seven minutes. Normally that would put any escaping pilot into a mind-bending panic.

He wasn't too worried. He knew he could travel a thousand times faster than the one click an hour closing speed of the two asteroids and was already hundreds of times faster. He decelerated when he decided to watch the impact. Putting the ship into a coasting routine, making sure there was nothing in front for at least an hour and checking the proximity alarm was active, he set up cameras and settled to watch through the aft view-port.

It was as eerie as it was fascinating. There they were, two celestial masses slowly closing in on each other each blissfully unaware of the other's presence.

The convergence was in awful languor. Moments before they touched, it seemed as if time stood still. A dilatory pause in space. Singer sat spellbound as the incoming intruder closed in.

The point of contact grew darker as the umbra-shadow crept over the craters. Then, the unique sight of the mountain tops of one world grazing the summits of another. Millions of tons of rock and dust pushed each other over as crumbling slow avalanches started to obscure Singer's view of the contact point. It didn't seem right that the grinding together of two flying mountains should be in silence. It didn’t seem fair. At least it was witnessed.

Worlds might end here–unheard. Nevertheless, the impact did send seismic perturbations through both asteroids. Singer improved his vision by using radar and microwave imagery that filtered out the finer fragments. His heart raced with excitement as he witnessed the extended pulverisation of mountain ranges. Instant lava flows increasingly splattered in vivid colours. Another mountain had its summit touched and then atomised by the incoming giant.

He found breathing painful, gasping. It must be the excitement. His hands quivered as he attempted to adjust vision controls. The occasion of more than a lifetime.

A black thought penetrated his exultation, and he glanced at the forward screens. Clear. Why had he thought he was heading towards something? The hardware would've warned him... as long as he'd set it correctly. He’d better check the manuals again. It was a nuisance he couldn't rely on the ship protecting him automatically just because of its damned logic and protocol. Besides every second spent re-reading the manuals would be precious moments away from the spectacle. He looked up.

The incoming asteroid seemed to be bigger. It was no longer a spheroid: the impact area had merged into the crust but the sides still had some curved form.

The metallic asteroid that he had been strolling about on appeared to be intact while the softer intruder was breaking up into huge pieces.

Singer grinned as he contemplated his future. Not only will he have a priceless record of this collision and the valuable samples in the hold to make him first famous then rich but it looked as if he might be able to scoop up more after the collision.

An ear-penetrating whine shook him. A proximity alarm. Part of the incoming asteroid had exploded and shards as big as a house headed his way.

AND SO IT WAS that he was trying to identify the whining noise as he was sailing through space in the escape pod. He was without the record of the collision to make him famous and without the samples to make him rich. He fingered a lump in his breast pocket... he smiled ruefully at the feel of the only fragment left, a souvenir.

Now what? A bright orange light was blinked furiously at him. The closing presence of a craft homing in on his distress beacon. He hoped it was his company’s rescue craft and not a rival’s elimination mission. He initiated a routine to enable stealth and to listen into radio signals with auto translation.

Singer adjusted volume and tweaked language diagnostic and translation parameters, then listened as he hovered a finger over the Respond button if they were genuine rescuers.

Crackles, and then:

"It should be somewhere around here.”

"Come on. Giracci, we've been searching co-ordinates for eighty hours. That signal must've been a passing vessel and it’s passed. Let's go."

"No. All the analysis indicates that one of the signals came from a wreck and the decoders are certain that it told of a manned escape vehicle."

"OK then, where is it?"

"Suppose it was you out there, hoping to be rescued but some would-be rescuer had a late appointment with his girl and..."

'I'm still here, aren't I?  Though I'm with Gvinlic who reckons that they can't be distress calls. They're in no code that's been used to date, they're on the wrong frequency for emergencies and no one is scheduled to be here."

"That cannot be an excuse..." their argument dopplered away.

Singer realized they were a genuine if strange rescue mission, but his radar gave him false readings of size and position. Now he was losing them so he turned his escape pod and headed for the signal source.

Damn, the proximity alarm battered his ears, but at least the radio became audible again.

“Still nothing, Giracci. Let’s go home.”

“Hey, what’s that? Something’s hit the forward viewscreen.”

“Yeah, probably a micrometeorite. It’s cracked the outer layer.”

Singer, dazed, struggled to ensure his helmet was on, as the pod disintegrated around him.