Rohas again studied the table of results. Logic suggested that the best hope of damaging the object was to get all the heavy guns to fire simultaneously. One of the ships had made its strike a few milliseconds later than was required of it in accordance with the calculations. The General called the ship’s commander.
“Rohas here. You were late with your strike. What happened?” he asked, not bothering to phrase the question more tactfully.
“The object dropped a false target right on my line of aim. The computer had to delay firing or I would have hit the decoy,” replied the commander.
“Operator!” called Rohas, addressing one of his subordinates in the command compartment. “Alter the strike synchronisation parameters. The ships must only begin the attack when there are no decoys blocking the view of the target.”
“Sir, under those new conditions, and assuming there are ten false targets, we lose about 65 milliseconds. Due to the increased distance, the probability of a hit from at least two guns simultaneously is lower than it was by two and a half per cent,” reported the operator when the computer had recalculated the combat parameters and restored them to the screen.
“Sixty-five milliseconds? How far is that in terms of distance?” asked Rohas.
“About 15,000 kilometres at three-quarters c, sir,” was the reply.
“Right. Make another alteration to the calculation model. Let it take account of the number of false targets. If there are too many of them, we must strike directly through them. They will be too light in weight to scatter the energy of the strike to any great extent. But don’t lose sight of the probability of hits by direct strikes. I need 99 percent for two direct hits simultaneously.”
“Yes, sir!”
“Sir, a message for you from Base,” reported the communications operator.
“Put it on my screen,” ordered Rohas.
The text appeared in front of the General’s face. He quickly looked through it:
“Urgent. Carry out radar scan of object 7N. Use all available radar sets for the maximum precision of determining its location. Coordinates of object...”
Rohas frowned. What nonsense was this? Don’t they think I have enough to do already? Then he turned his attention to the object’s coordinates. So far from the plane of the ecliptic?
The General gestured for the object to be visualised on the map of the Solar System. It was certainly a long way from the usual routes, and flying on a very strange trajectory, far from any planets. Where the devil was it going? What was this, a hijack? Not that it mattered.
“Task from the General Staff,” he said to his Second Mate, sending him the message just received. “Read and execute. And find out what ship this is.”
“Yes, sir!”
Rohas deleted the base’s message from the screen and went back to studying the results of the simulated battle. The electronic intelligence officer came online.
“Sir, we have just registered a weak signal in the gravity band, apparently broadcast by the object.”
“What do you mean, ‘apparently’?”
“We don’t have any instruments for monitoring gravitational waves; we obtain this information from a civilian observatory on Earth. The resolution of their equipment leaves something to be desired. And it’s a considerable distance,” said the officer, in a somewhat self-justifying tone.
“Understood. What information can we get out of the signal?”
“The pulse was very short, too short to carry much information. They are probably communicating in prearranged codes.”
“Was it a specific-direction signal?”
“No, it was omni-directional.”
“Cunning buggers,” laughed Rohas. “OK. If you manage to intercept the reply, let me know at once.”
He looked at the clock. The object only had a little more than thirteen hours left till the ultimatum expired. Allowing for the maximum possible speed of transmission of the signal, the object’s base must be within a sphere of radius of six and a half light hours. It was pretty hopeless to comb through such a huge sector with radars.
“Look carefully for any peculiarity within a distance of up to seven light hours. Anything out of the ordinary, anything strange, let me know at once. But don’t use the radars. Better not let it know we are covering the gravity waveband too. They are no use at that distance anyway. Execute!” ordered Rohas.
“Wilco,” replied the electronic intelligence officer, and switched off.
Rhino at the water hole
The rapidity of the possible space battle in Jupiter’s vicinity meant that people had to be removed from the direct decision-making process. A few microseconds would not be enough for a human brain to assess the complex situation in the theatre of military operations and select the best plan of attack and interaction of a large number of attack units. Computers would do this for it. The only human role was to input a program and determine the strategy; electronic brains would take the tactical decisions.
The essence of the plan of attack on the alien ship was quite simple. In the event of it breaching the terms of the blockade, it would be hit with a crushing blow from all available weapons, as well synchronised as possible, thus maximising the total energy of the attack.
The difficulty was in synchronising the strikes. It was calculated that the alien ship, in breaching the blockade and taking an evasive manoeuvre against the strike, would try to reach the maximum speed available to it. The battle plans were based on the assumption that the limit of its capabilities would be reached at three quarters of the speed of light. In that case, the pulse fired by the pulse weapon would exceed the target’s speed only by a third. This being the case, the problem of achieving a synchronous strike was by no means a trivial one.
Since the blockade had been deployed round Jupiter, Rohas frequently practised alarms, simulating all possible combat situations in search of the optimum strike strategy. Having obtained the results from the latest virtual battle, Rohas immersed himself in studying the weak points, then issued commands to the weapons operator to optimise the interaction. With every exercise, the probability of destroying the object increased. The General knew his business.
“Mission accomplished, sir. Permission to send the data to the command centre?” asked the Second Mate, who had finished scanning the large cargo ship.
“Did you find out what sort of ship it is?” asked Rohas, taking his mind off battle simulations.
“It’s a civil ore carrier, serial number THP 11600. Something’s going on there, it seems to be evading pursuit. Or it’s been hijacked.”
“Why would the General Staff be interested in it?”
“I have no idea, Sir.”
“Hmm... Did you notice anything strange about it?”
“It has an untypical radar shadow for that type of ship, the signature is strongly distorted. But judging by its acceleration, its engines are working normally. So it can’t be an emergency. Otherwise, nothing in particular.”
“OK, it’s none of our business, send the data,” said Rohas, closing the subject and returning to his work.
Suddenly an alarm signal rang out in the command compartment.
“Attention! Static heavy weapon E1 is unblocked and at battle readiness,” reported the command computer, which received data from all the heavy weapons of the blockade group.
“Attention second echelon, combat alarm!” roared Rohas into the microphone.
At the same time, he brought the main parameters of E1 up on the screen. In the corner, in bold letters, a red text box was flashing:
“MODE: COMBAT”
The capacitors of the static weapons were in charged condition, ready to strike at any moment, but until receipt of an order from the central computer, their electronic ‘safety catch’ prevented the gun firing. The E1’s safety catch could only be taken off either from the command post, or by the gun crew on the spot. By going to ‘Combat’ regime, E1 had been cocked.
The General got in laser contact
with the gun operator.
“Owl calling Rhino, over.”
No reply.
“Owl calling Rhino, over.”
Rohas waited a few seconds, still receiving no reply, then made contact with the second echelon ships.
“Owl calling Hunter, over.”
“Owl, this is Hunter, hearing you loud and clear,” the commander of the second echelon replied instantly.
“Rhino has left the herd and is going to the water hole.”
“Roger.”
“Chase it back!” roared Rohas.
“Wilco.”
Rohas glanced at the visualisation of the alien ship’s trajectory. From the location of E1, it was now behind the cover of the planet, but in a few minutes the incomer would be in the direct field of vision of a combat-ready weapon. The unauthorised switch to combat regime of one of his most powerful weapons, with which he had no communication, was a disaster, one that was rapidly developing before the General’s eyes.
He switched on the gun’s remote control and tried to bring it back out of combat regime. Rohas pressed the emergency off switch several times, but without success. Not having achieved any result, he ceased his attempts to switch off the weapon, leaned back in his chair and folded his arms across his chest.
“Put the image of E1 on the main screen,” he ordered the computer.
The image of the grey surface of Europa, covered with thick layers of ice, appeared on the big screen in the centre of the command compartment. E1 could hardly be seen against the background of ice speckled with occasional cracks. If it had not been for the long shadow of the magnetic guides pointing upwards, the gun would have been difficult to distinguish from the natural landscape. The living accommodation could be seen a little way from the unusually long and uniform shadow of the gun barrel. On the other side lay a huge reactor, surrounded by a honeycomb of capacitor containers.
The General patiently observed the image, which appeared static. Europa had no atmosphere worth mentioning, so there were no winds on its surface. Because of this, the live picture could only be distinguished from a photograph by the shadow crawling slowly after the dim sun.
“Overlay with the distance grid,” Rohas said to the computer.
At the same second, a circle consisting of a fine green line appeared round the gun barrel. Straight lines extended out from this circle in all directions, like the sun’s rays, and on them, circles at uniform distances from the centre of the gun. The circles were at a spacing of one kilometre.
Suddenly, between the fifth and sixth circles from the barrel of E1, there appeared a white fountain of what might have been snowflakes, or stones, or foam splashes. One of the second echelon ships had just fired a warning shot to attract the attention of the gun crew.
On the picture transmitted to the command compartment where Rohas was sitting, the explosion was noiseless, creating the deceptive impression that its power might have been insufficient to attract the attention of the heedless gun personnel. Nevertheless, its force had been calculated beforehand so that it would create a real earthquake in E1’s living accommodation. At this moment, it must be chaotic down there, with all sorts of objects from the shelves and tables lying on the floor. Only the dead could fail to notice such a shake-up.
Rohas, with an indifferent expression on his face, watched the fountain emanating from the epicentre of the explosion rising higher. Free-fall acceleration on Europa was even less than on the Moon, so the ice thrown up from the surface of the satellite was in no hurry to settle back down. On the contrary, its shadow was seen to be growing longer and longer, until it slowly began to disintegrate at the tip.
The General then looked at the screens in front of him, on which the gun’s parameters could be seen. E1 was still cocked, ready to fire at the object at any moment, as soon as it reached a convenient position for a direct shot. Apparently the warning shot had not had the desired effect on the gun crew.
Those people in E1’s living accommodation knew very well the scenario according to which further events would develop. Even if all their electronics had become unserviceable and they could neither control E1 nor contact their commander, they ought to give some sign, fire a rocket or show a winking laser. Now practically the whole strike group was literally looking in their windows. If the warning shot did not produce an effective reaction, the next shot would be aimed directly at the gun’s magnetic guides. The living compartments, only a few hundred metres from the barrel, would most likely not survive the strike and would become unsealed.
Rohas observed the situation without losing sight of the position of the alien ship. It was already approaching the south pole from the other side of Jupiter, and should soon come out of the shadow. A few more seconds and it would become clearly visible to E1, entering the gun’s target zone.
The General waited patiently for any reaction at all from E1’s gun crew. They had hardly any time left. Even if they got in touch but did not manage to avert the threat, their fate would be unenviable. Rohas had no right to risk starting an armed conflict with the superior forces of the enemy due to electronic failure or incompetence.
“Attention! The object has come out of the shadow, thirty seconds before it enters E1’s target sector,” reported the command computer.
Rohas had less than ten seconds to give the order to cancel the attack on E1. If no such order was given, one of the second echelon ships would neutralise the rogue gun.
The human psyche is such that at such moments, a stream of doubts about the correctness of one’s actions rushes through the mind. What had happened on Europa? Was it just some stupid cock-up? Maybe he should give the gun crew more time? Perhaps he ought not to be taking one of his most powerful weapons out of the group’s armoury because of some misunderstanding? Rohas was no exception, and his head was full of such thoughts at this moment. But as the commander, he knew this weak side of the human brain and did not allow it to prevail over his reason. The protocol for such a situation had been well thought out and fine-tuned to the last detail. It could not be breached.
“Attention! The object is entering the target zone. Neutralisation of E1 in two seconds,” reported the computer.
By taking E1 out, the chances of a successful attack on the alien ship would be significantly reduced. Rohas realised this, and this was why he was delaying as long as possible. This was his last chance to stop the second echelon.
The cloud
Steve and Clive had just finished working on a computer model for analysing the telemetry of the space traffic, when they heard the locks of the entry door clanking. In the silence of the room, broken only by the rustle of the air conditioning coming from the ventilation slots under the ceiling, the loud sound made them jump, it was so unexpected.
Shelby appeared in the open doorway, escorted by two officers of the guard. It appeared that they had accompanied him from the situation room. Civilians were not allowed in the security zone without military supervision. Apparently even Shelby was no exception to this rule.
“I’ve just received a message from Rohas,” he said, and noticing the questioning expression on Steve’s face, explained: “Major-General Rohas, commander of the blockade round Jupiter. He has sent me the scanning results.”
When Shelby came closer to the table, Clive noticed he had a tablet in his hands.
“I thought they were forbidden here,” he said, pointing to the gadget.
“The military issued me with this one,” replied Shelby, fiddling about with it.
“Right, I’ve found it,” he said eventually. At this moment, the contents of a file were transferred to the computers standing on the table. The Professor laid the tablet aside. “Let’s look together at what they’ve sent us.”
Clive fed the data into their new model, which gobbled them up and at once spat out the result. “Now we’ll see... It’s ready,” he muttered to himself.
Columns of figures appeared on the screen, intermingled with tables. All three gazed intently a
t the display. After a brief pause for thought, Shelby pointed to one of the tables.
“How do you calculate the measurement of inertia?” he asked.
Listening to Clive’s replies to Shelby’s questions, Steve continued to be amazed at how quickly the Professor had grasped how their model worked. Due to lack of time, they made a print-out of the results, functional but not at all intuitive. It was barely possible to make sense of the columns of figures as you were running through them, thought Steve. All the same, appearances might be deceptive; in spite of his age and the fact that he looked like a typical old man, Shelby had a mind like a steel trap.
Eventually, Shelby took off his spectacles with his familiar gesture, which meant he had mastered the subject matter and a full picture of the situation had formed in his brain. He went to the wall which served as a monitor and an electronic blackboard at the same time. He rapidly sketched a three-dimensional map of the Solar System, put in the main landmarks and noted the orbits of the planets. The three-dimensional projection of the sketch was so effective that it seemed to be standing out from the monitor. Steve had noticed from Shelby’s lectures how well developed his ability to think in three dimensions was, and how easily he could create a three-dimensional impression in a sketch using only a few lines.
“So that means, on the basis of the calculation results of your model, we have a deviation in these sectors here and here,” Shelby was talking aloud to himself and pointing to the location of the anomaly.
“If we extrapolate the data,” he continued, marking the relevant positions with vertical lines, “the anomaly changes by two tenths per mille every four hundred million kilometres. Right?”
Steve and Clive nodded in agreement.
“Then we have negligibly small or even zero deviation somewhere around the centre of the Solar System, but the further away from the sun, the stronger it gets,” the Professor summed up and he fell silent, deep in thought.
The Contact Episode Four Page 6
