Rama II r-2

by Arthur C. Clarke

  “There was a time,” Reggie mused out loud, shaking his head, “when things were very different.” He glanced at Francesca. There was no indica­tion that she was even listening. “Back when I still believed in love,” he said in a louder voice. “Before I knew about betrayal. Or ambition and its selfish­ness.”

  He jerked the rover wheel vigorously to the left and brought it to a stop about forty meters west of the biots. Francesca jumped out without a word.

  Within three seconds she was chattering to David Brown and Richard Wakefield on the radio about the video coverage of the capture. The ever polite Dr. Takagishi thanked Reggie Wilson for driving the rover.

  “We’re coming in,” Tabori shouted from above. He managed to position the dangling nexus properly on his second attempt. The nexus was a round, heavy sphere about twenty centimeters in diameter, with a dozen small holes or indentations on its surface. It was slowly dropped onto the center of the shell of one of the outside biots. Next Janos, transmitting a barrage of com­mands from the hovering helicopter to the processor in the nexus, ordered the extension of the massed threads of metal rolled up inside the sphere. The crabs did not stir as the threads wrapped themselves around the target biot.

  “What do you think, inspector?” Janos hollered at Richard Wakefield in the other helicopter.

  Richard surveyed the strange apparatus. The thick cable was attached to a ring stanchion at the rear of the helicopter. Fifteen meters below, the metal ball sat on the back of the target biot, thin filaments extending from inside the ball around the top and bottom of the carapace. “Looks fine,” Richard replied. “Now there’s only the single question remaining. Is the helicopter stronger than their collective grip?”

  David Brown commanded Irina Turgenyev to lift the prey. She slowly increased the speed of the blades and tried to ascend. The tiny slack in the cable disappeared but the biots barely moved. “They’re either very heavy or they’re holding onto the ground somehow,” Richard said. “Hit them with a sharp burst.”

  The sudden jolt in the cable lifted the entire biot formation momentarily skyward. The helicopter strained as the biot mass dangled two or three meters off the ground. The two crabs not attached to the target biot dropped first, falling into a motionless heap seconds after takeoff. The other three crabs lasted longer, ten seconds altogether before they finally disengaged their claws from their companion and fell to the ground below. There were universal cries of joy and congratulations as the helicopter climbed higher into the sky.

  Francesca was filming the capture sequence from a distance of about ten meters. After the last three biots, including the leader, had released their grips on the target crab and fallen onto the Raman soil, she leaned back to record the helicopter as it headed for the banks of the Cylindrical Sea with its prey. It took her two or three seconds to realize that everyone was shout­ing at her.

  The lead biot and its final two companion crabs had not crumbled into a heap when they had hit the ground. Although slightly damaged, they were active and on the move within moments after landing. While Francesca was filming the departure of the helicopter, the lead biot sensed her presence and headed toward her. The other two followed a step behind.

  They were only four meters away when Francesca, still filming, finally understood that she was now the prey. She turned around and started to run. “Run to the side,” Richard Wakefield screamed into the communicator, “they can only go in straight lines.”

  Francesca zigged and zagged but the biots continued to follow her. Her original burst of adrenaline enabled her to extend the distance separating her from the crabs to ten meters. Later, however, as she began to tire, the relentless biots were closing in on her. She slipped and almost fell. By the time Francesca regained her stride the lead biot was no more than three meters away.

  Reggie Wilson had raced toward the rover as soon as it was clear that the biots were chasing Francesca. Once he was at the controls of the vehicle, he headed for her rescue at top speed. He had originally intended to pick her up and move her out of the way of the biot onslaught. They were too close to her, however, so Reggie decided to smash into the three crabs from the side. There was a crash of metal on metal as the lightweight vehicle rammed the biots. Reggie’s plan worked. The momentum of the crash carried Reggie and the crabs several meters to the side. The threat to Francesca was over.

  But the biots were not incapacitated. Far from it. Despite the fact that one of the follower crabs had lost a leg and the lead biot had a slightly damaged claw, within seconds all three of them were at work in the wreck­age. They started slicing the rover into chunks with their claws, and then they used their fearful collection of probes and rasps to tear the chunks into still smaller pieces.

  Reggie was momentarily stunned by the impact of the rover against the biots. The alien crabs had been heavier than he had anticipated and the damage to his vehicle was severe. As soon as he realized that the biots were still active, he started to jump out of the rover. But he couldn’t. His legs were wedged underneath the collapsed dashboard.

  His unmitigated terror lasted no longer than ten seconds. There was noth­ing anyone could do. Reggie Wilson’s horrified shrieks echoed through the vastness of Rama as the biots chopped him apart exactly as if he were part of the rover. It was accomplished swiftly and systematically. Both Francesca and the automatic camera in the helicopter filmed the final seconds of his life. The pictures were transmitted live back to the Earth.

  30

  POSTMORTEM II

  Nicole sat quietly in her hut at the Beta campsite. She could not erase from her mind the horrible image of Reggie Wilson’s face, contorted in terror as he was being hacked to pieces. She tried to force herself to think of something else. So what now, she wondered. What will happen to the mission now?

  Outside it was dark again in Rama. The lights had vanished abruptly three hours before, after a period of illumination thirty-four seconds less than during the previous Raman day. The disappearance of the lights should have prompted much discussion and speculation. But it didn’t. None of the cos­monauts wanted to talk about anything. The awful memory of Wilson’s death weighed too heavily on everyone.

  The normal crew meeting after dinner had been postponed until morning because David Brown and Admiral Heilmann were in an extended confer­ence with ISA officials back on Earth. Nicole had not participated in any of the conversations, but it was not difficult for her to imagine their content. She realized that there was a very real possibility the mission would now be aborted. The hue and cry from the public might demand it. After all, they had witnessed one of the most gruesome scenes…

  Nicole thought of Genevieve sitting in front of the television at Beauvois, watching while Cosmonaut Wilson was being methodically subdivided by the biots. She shuddered. Then she chastised herself for being self-centered. The real honor, she said to herself, must have been in Los Angeles.

  She had met the Wilson family twice during the early parties right after the crew selections were announced. Nicole remembered the boy particu­larly. Randy was his name. He was seven or eight, wide-eyed and beautiful. He loved sports. He had brought Nicole one of his prized possessions, a program from the 2184 Olympics in nearly perfect condition, and had asked her to sign the page featuring the women’s triple jump. She had tousled his hair as he had thanked her with a huge smile.

  The image of Randy Wilson watching his father die on television was too much for her. Several tears wedged themselves into the corners of her eyes. What a nightmare this year has been for you, little boy, she thought. The roller coaster of life. First the joy of having your father selected as a cosmo­naut. Then all the Francesca nonsense and the divorce. Now this terrible tragedy.

  Nicole was becoming depressed and her mind was still too active for sleep. She decided that she wanted some company. She walked over to the next hut and knocked softly on the door.

  “Is someone out there?” she heard from inside.

  “Hot, Takagishi-sa
n,” she replied. “It’s Nicole. May I come in?”

  He walked over to the door and opened it. “This is an unexpected sur­prise,” he said. “Is the visit professional?”

  “No,” she answered as she entered. “Strictly informal. I was not ready to sleep. I thought—”

  “You are welcome to visit me any time,” he said with a friendly smile. “You do not need a reason.” He looked at her for several seconds. “I am deeply disturbed by what happened this afternoon. I feel responsible. I don’t think I did enough to stop—”

  “Come on, Shigeru,” Nicole replied. “Don’t be ridiculous. You’re not to blame. At least you spoke up. I’m the doctor and I didn’t even say any­thing.”

  Her eyes wandered aimlessly around Takagishi’s hut. Beside his cot, sitting on a small piece of cloth on the floor, Nicole saw a curious white figurine with black markings. She walked over to it and bent down on her knees, “What’s this?” she asked.

  Dr. Takagishi was slightly embarrassed. He came over beside Nicole and picked up the tiny fat oriental man. He held it between his index finger and his thumb. “It’s a netsuke heirloom from my wife’s family,” he said. “It’s made from ivory.”

  He handed the little man to Nicole. “He is the king of the gods. His companion, a similarly plump queen, rests on the table beside my wife’s bed in Kyoto. Back before elephants became endangered, many people collected figures like this. My wife’s family has a superb collection.”

  Nicole studied the little man in her hand. He had a benign, serene smile on his face. She imagined the beautiful Machiko Takagishi back in Japan and for a few seconds she envied their marital bond. It would make events like Wilson’s death much easier to deal with, she thought.

  “Would you like to sit down?” Dr. Takagishi was saying. Nicole positioned herself on a box next to the cot and they talked for twenty minutes. Mostly they shared memories of their families. They referred obliquely to the after­noon disaster several times, but they avoided detailed discussion of Rama and the Newton mission altogether. What they both needed were the com­forting images of their daily lives on Earth.

  “And now,” Takagishi said, finishing his cup of tea and putting it on the end table beside Nicole’s, “I have a strange request for Dr. des Jardins. Would you please go over to your hut and bring back your biometry equip­ment? I would like to be scanned.”

  Nicole started to laugh but noticed the seriousness in her colleague’s face. When she returned with her scanner several minutes later, Dr. Takagishi told her the reason for his request. “This afternoon,” he said, “I felt two very sharp pains in my chest. It was during the excitement, after Wilson crashed into the biots, and I realized…” He did not complete his sentence. Ni­cole nodded and activated the scanning instrument.

  Neither of them said anything for the next three minutes. Nicole checked all the warning data, displayed graphs and charts of his cardiac performance, and shook her head regularly. When she was finished she faced her friend with a grim smile. “You’ve had a slight heart attack,” she said to Dr. Takagi­shi. “Maybe two very close together. And your heart has been irregular ever since.” She could tell that he had expected the news. “I’m sorry,” she said. “I have some medicine with me that I can give you, but it’s only a stopgap measure. We must go back to the Newton immediately so we can treat this problem properly.”

  “Well.” He smiled wanly. “If our predictions are correct, then it will be light again in Rama in about twelve hours. I assume we’ll go then.”

  “Probably,” she answered. “I’ll talk to Brown and Heilmann about it right away. My guess is that you and I will leave first thing in the morning.”

  He reached out and took her hand. “Thank you, Nicole,” he said.

  She turned away. For the second time in an hour there were tears in the corners of her eyes. Nicole left Takagishi’s hut and headed for the edge of camp to talk to David Brown.

  “Ah, it is you.” She heard Richard Wakefield’s voice in the dark. “I thought for certain you were asleep. I have some news for you.”

  “Hello, Richard,” Nicole said as the figure holding the flashlight emerged from the darkness.

  “I couldn’t sleep,” he said. “Too many grisly pictures in my head. So I decided to work on your problem.” He smiled. “It was even easier than I thought. Would you like to come to my hut for an explanation?”

  Nicole was confused. She had been preoccupied with what she was going to say to Brown and Heilmann about Takagishi. “You do remember, don’t you?” Richard inquired. “The problem with the RoSur software and the manual commands.”

  “You’ve been working on that?” she asked. “Down here?”

  “Certainly. All I had to do was have O’Toole transmit the data that I needed. Come on, let me show you.”

  Nicole decided seeing Dr. Brown could wait for a few more minutes. She walked beside Richard. He knocked on another hut as they went by. “Hey Tabori, guess what?” he shouted. “I found our lovely lady doctor wandering around in the dark. Do you want to join us?”

  “I explained some of it to him first,” Richard said to Nicole. “Your hut was dark and I figured you were asleep.”

  Janos stumbled out of his door less than a minute later and acknowledged Nicole with a smile. “All right, Wakefield,” he said, “but let’s not prolong it. I was finally drifting off.”

  Back in Wakefield’s hut, the British engineer thoroughly enjoyed recount­ing what had happened to the robot surgeon when the Newton had experi­enced the unexpected torque. “You were right, Nicole,” he said, “that there were manual commands input to RoSur. And these commands did indeed shut down the normal fault protection algorithms. But none of them was input until during the Raman maneuver.”

  Wakefield smiled and continued, watching Nicole carefully to ensure that she was following his explanation. “Apparently, when Janos fell and his fingers hit the control box, he generated three commands. At least that’s what RoSur thought; it was told that there were three manual commands in it’s queue. Of course they were all garbage. But RoSur had no way of know­ing this.

  “Maybe now you can appreciate some of the nightmares that plague sys­tem software designers. There’s just no way anybody could ever anticipate all possible contingencies. The designers had protected against one inadvertent garbage command — someone brushing the control box during an operation, for example — but not several bad commands. Manual commands were essen­tially considered to be emergencies by the overall system design. Hence they had the highest priority in the interrupt structure of the RoSur software and were always processed immediately, The design acknowledged, however, that there could be a single “bad” manual command and had the capability of rejecting it and moving on to the next priority interrupts, which included fault protection.”

  “Sorry,” said Nicole. “You’ve lost me. How could a design be structured to disregard a single bad command, but not several? I thought this simple processor operated in series.”

  Richard turned to his portable computer and, working from notes, called up on the monitor a mass of numbers arrayed in rows and columns. “Here are the operations, instruction by instruction, that the RoSur software imple­mented after there were manual commands in its queue.”

  “They repeat,” Janos observed, “every seven operations.”

  “Exactly,” Richard replied. “RoSur tried three times to process the first manual command, was unsuccessful in each attempt, and then went on to the next command. The software operated exactly as it was designed—”

  “But why,” Tabori asked, “did it go back to the first command after­ward?”

  “Because the software designers never considered the possibility of multi­ple bad manual commands. Or at least never designed for the condition. The internal question the software asks after finishing with the processing of each command is whether or not there is another manual command in the buffer. If there is not, then the software rejects the first com
mand and is free to handle another interrupt. If there is, however, the software is told to store the rejected command and process the next command. Now, if two com­mands in a row are rejected, the software assumes that the command proces­sor hardware is broken, swaps to the redundant hardware set, and tries again to process the same manual commands. You can understand the reasoning. Suppose one…”

  Nicole listened for several seconds as Richard and Janos talked about redundant subsystems, buffered commands, and queue structures. She had very little training in either fault protection or redundancy management and could not follow the exchange. “Just a moment,” she interjected at length, “you’ve lost me again. Remember, I’m not an engineer. Can’t somebody give me a summary in normal English?”

  Wakefield was apologetic. “Sorry, Nicole,” he said. “You know what an interrupt-driven software system is?” She nodded. “And you are familiar with the way priorities operate in such a system? Good. Then the explana­tion is simple. The fault protection interrupts based on the accelerometer and imaging data were lower priority than the manual commands inadver­tently entered by Janos when he was falling. The system became locked in a software loop trying to process the bad commands and never had a chance to heed the fault signals from the sensor subsystems. That’s why the scalpel kept cutting.”

  For some reason Nicole was disappointed. The explanation was clear enough, and she had certainly not wanted the analysis to implicate Janos or any other member of the crew. But it was too simple. It had not been worth all her time and energy.

  Nicole sat down on the cot in Richard Wakefield’s hut. “So much for my mystery,” she said.

  Janos sat beside her. “Cheer up, Nicole,” he said. “This is good news. At least now we know for certain that we didn’t foul up the initialization pro­cess. There’s a logical explanation for what happened.”