Starquake

by Robert L. Forward

Pierre hesitated. The image flickered.

  The real decision had been made long ago. Pierre touched the screen in front of him, and the coordinates were transferred to the herder rockets that kept Otis on its desired path. Pierre then pushed the execute square on his touch screen. The engines on the herder rockets flared. Within seconds Otis was on a new trajectory that would take it within a few meters of the surface of Dragon's Egg.

  21:02:20 GMT TU6SDAY 21 JUNE 2050

  Push-Pull looked up from his testing apparatus to stare out at the herder rockets that swarmed around Otis. "There seems to be some activity in the large human spacecraft surrounding us."

  "I noticed," said Cliff-Web. "What is the status of the high flow-rate tubes?"

  "They passed flow tests at twice design pressures, and failed just above that," said Push-Pull.

  "Good, but too good. Reduce their thickness by a half-dozeth and test them again. I want this machine light enough to jump itself 40 meters off Egg."

  The construction of the four-centimeter-diameter self-levitating gravity lander took significantly less time than the larger machine. They were finished with nearly a great of turns left before Otis reached periapsis.

  Steel-Slicer came to see the completed lander. It was a torus sitting inside a larger torus.

  "What's its name?" Steel-Slicer asked.

  "It's just the lander," Cliff-Web replied with obvious annoy-

  ance. "It doesn't have a name except Egg Surface Descent Craft, if you want to be formal."

  "All ships have to have a name," said Steel-Slicer. "Since it flies above the surface of Egg it should have the name of some flying animal."

  "There are no flying animals on Egg." Cliff-Web was even more annoyed.

  "There are flying animals on the human planet Earth," Push-Pull interjected. "One of them is the eagle."

  "Eagle it shall be." Steel-Slicer declared.

  "If you say so," said Cliff-Web.

  "Is there anything else we should do?"

  "I would do some thinking," said Cliff-Web. "Once we have landed on Egg, there is no way to get off again until we have rebuilt civilization. We are mass limited and must only take the things we will need. If we forget to take something, there is no going back. Tell me. What is the minimum list of skilled technologists and equipment you need to rebuild a civilization?"

  "I don't know," said Steel-Slicer.

  "Neither do I. But 122 turns from now we had better know."

  The turns passed as the members of the landing party were selected and their equipment was packed in the compounds constructed on the topside of Eagle. Egg grew larger in the sky, then disappeared behind the horizon of their miniature planet as the human herder rockets turned Otis until the gravity catapult was facing back along the orbital trajectory. With the light of Egg gone from the sky they had to make do with the dull glow from the surface of Otis. The cold reddish light put a pall over their last turnfeast together.

  The food preparers had done their best. Besides the large mounds of artificial foods from the food machines, there were a number of whole pet Slinks, especially fattened for the occasion and beautifully garnished with fresh nuts and fruits from the gardens that had been started on Otis from artificially fabricated seeds shortly after they had arrived. The center of attention, however, was a whole roast cheela. The body was badly flattened from a fall off the scaffolding around the gravity catapult, but that didn't hurt the taste. Steel-Slicer and Cliff-Web decided not to try to push through the crowd and settled for one of the Slinks.

  "Excellent Slink," Steel-Slicer said, sucking the eye off an eye-stub chunk.

  "Not as good as food Slinks back on Egg," said Cliff-Web.

  "I've been trying to forget they exist."

  "Back when I was on Egg, I never really paid much attention to my food," Cliff-Web said. "At turnfeast I would just stuff my pouches as if I were recharging a machine. Now that we are getting close to returning to Egg, my pouches are beginning to ache for a decent chunk of food Slink or a squirt of South Pole singleberry juice."

  "It has been so long...." The Steel-Slicer turned silent as he thought of the agony and hopeless despair the two separated groups of cheela had undergone over dozens and dozens of generations. Although he had just undergone rejuvenation again, he felt old and tired.

  The following turn passed rapidly. The elevator on the Space Fountain was in continuous operation as the base on Otis was abandoned and most of the cheela returned to their spacecraft. All that were left were the brave 144 that were to fly down to Egg on Eagle.

  On the crust of Otis, Cliff-Web watched the cargo ship pull away from the top of the Space Fountain. Once it was clear, he flicked his eye-stubs at an engineer who was waiting at the controls. The engineer made an adjustment, and the high-pitched whine coming through the crust started to drop in tone. Slowly the tower grew shorter and shorter. Soon the tower was reduced to a pile of metal rings and a stack of platforms. It might have been simpler to turn off the stream of rings and let the tower fall, but Cliff-Web didn't want any stray projectiles orbiting around Otis and dropping on Eagle.

  Their next task was to charge up the flow tubes on Eagle.

  "Attach the power cables to the pumps on Tube Array 1," said Cliff-Web. Large masts rose from holes in the crust and coupled to two dozen pumps spaced around the periphery of Eagle. The pumps hummed to life, and the ultra-dense black-hole dust circulated faster and faster in the array of tubes. The hull of Eagle creaked as the fluid reached relativistic velocities; still the pumps pushed. The fluid became heavier instead of moving faster, and the gravity potentials inside the torus became so intense that they could no longer be described by the old Einstein theory. The rate of change of flow rate had been slow, however, so the gravity repulsion forces generated in the hole of the torus had been negligible.

  Cliff-Web felt the whining of the pumps reach a peak and level off. Eagle now had one of its two multi-tube arrays charged with energy in the form of high speed ultra-dense mass. It was time for them to leave.

  "Switch to internal power," he said. There was a hesitation in the sound as the pumps were switched from the outside power connectors to internal stored power. The stored power to compensate for friction and gravitational radiation losses would only last a few milliseconds, so they had to be on their way. He watched as the huge power conductors that had energized Eagle were retracted from their connectors on the hull and lowered down into holes in the crust. Eagle, perched on its launching pad, was now free to fly.

  Cliff-Web, his engineer's part done, stopped the normal wave motion of four of his eye-stubs and stared at Otis-Elevator.

  "Eagle ready for launch, Captain," said Cliff-Web.

  Otis-Elevator waited as the motion of Otis took the dot on the tread screen beneath him along its plotted path. The orbit would take Otis within 100 meters of the surface of Egg, where it would pass over the surface at one-third the speed of light. There were rumblings in the crust of Otis as the tidal forces from Egg attempted to pull the planetoid apart. Cliff-Web anxiously looked out in all directions, hoping that the crust in this region would hold together for a few more microseconds.

  Just before the planetoid reached its periapsis, the captain acted. "Launch!" commanded Otis-Elevator. His tread moved rapidly over the touch screen beneath him and neutrino beams sent out coded signals from Eagle to the machinery sitting around it. The power generators had been storing their power in temporary accumulators while waiting for the launch command. When the signal came, all the stored energy plus all the power that the generators could produce was switched into the pumps that drove the ultra-dense dust in the bigger gravity catapult.

  The pumps, shrieking from the high loads, pushed the dust in the twenty-centimeter-diameter torus at unbelievable accelerations. The moving stream of black holes generated a rapidly increasing gravitomagnetic field inside the torus. The increasing gravitomagnetic field in turn generated a repulsive gravitational field at the center of the torus. Eagle was re
pelled upwards at many times the gravity of Egg, but the crew felt

  nothing, tor the forces were gravitational. Eagle reached a third of the speed of light in two nanoseconds and left the surface of Otis to find itself hovering motionless 100 meters up over the outskirts of Bright. It started to fall.

  "Divert one-twelfth flow in Tube Array 1 to Tube Array 2," said Otis-Elevator.

  There was a pause, then the First Officer replied. "No response, Captain."

  "Try it again." Eagle built up speed as it fell.

  "I did, sir," First Officer Space-Treader responded. "The signals are being sent and received, but the diverter valve is not responding. It must be stuck!"

  "It's not stuck," interjected Cliff-Web. He transferred an image of the diverter valve from his engineer's screen to that of the two officers. "Someone forgot to remove the safety pin. You can see the glow-tab at the end." He flowed off the screen and headed for the inner railing that surrounded the hole in the torus.

  "Use some of our accumulator energy to slow the flow in Tube Array 1," he said as he squeezed his body beneath the railing. "We can't land using that, but it will slow our fall and give us more time."

  "Where are you going?" Otis-Elevator asked. The reply was distant and muffled, for the vibrations set up by Cliff-Web's tread had to make a circuitous path from the tubular engines of Eagle up to the command deck.

  "I'm going to pull that pin," said Cliff-Web.

  Cliff-Web found Tube Array 2 and made his way along the gigantic bundle of pipes that wound in layers around the toroidal body of Eagle. Fortunately, Eagle had enough self-gravity that he was in no danger of falling. As he neared the central hole in the ring he could see the crust of Egg below him. The captain had the pumps to Tube Array 1 on, but Eagle was still falling rapidly. Cliff-Web reached the juncture where Tube Arrays 1 and 2 connected through the diverter valve. As he got near Tube Array 1 his tread started to slip as the rushing ultra-dense dust inside the tube tried to drag him along in its inertial reference frame. He clenched his tread tighter against the smooth surface of Tube Array 2 and carefully made his way to the diverter valve. He pulled the pin and held it up to the video monitor.

  "Divert flow!" he shouted, hoping that they could hear him over the long distance through the hull.

  "I will wait!" roared the captain's amplified voice from the ship's general announcement system. "Hurry!"

  Cliff-Web looked at the rapidly approaching crust. Somewhere down there were dozens and dozens of bags of South Pole singleberry juice that he would never get to taste.

  "Too late!" Cliff-Web shouted. "Divert flow!"

  The diverter valve slammed. The ultra-velocity, ultra-dense dust switched from one Tube Array to the other. The change in gravity potential created an ultra-strong repulsive gravity field that pushed Cliff-Web from his perch near the diverter valve and threw him toward the crust below. There was a bright streak of incandescent plasma, and he was gone.

  Eagle's repulsor gravitational field reached out from the central hole in its hull and shoved against the mass of Egg below it. The spacecraft slowed its fall, Captain Otis-Elevator finally gained control. They couldn't afford to hover for long, since they would soon have diverted all the flow. Eagle had drifted over a small mountain range, and he would have to move them to a flatter landing place.

  Flying on the repulsive gravitational forces, Eagle coasted down the mountain slopes, causing minor crust-quakes as it made its own valley down a mountainside. They passed over a herd of animals grazing in the plains, scattering them in all directions. Then, with the last bit of stored energy surging through the pumps to augment the last of the diverted flow, they floated down to a landing. First Officer Space-Treader monitored the sensors and video monitors on the bottom of the hull.

  "... 200 millimeters ... four-and-a-half down ... contact indicator ... engine stop...."

  There was a pause as the heavy machine sank slightly into the crust, then 'trums and electronic whistles sounded as Captain Otis-Elevator announced through the neutrino communication link to the waiting ships in orbit.

  "East Pole Station! Dragon's Egg Base here. The Eagle has landed!"

  Cheers vibrated throughout the hull of Eagle and were echoed by the communications console under Admiral Steel-Slicer's tread. He did not join in, however, for all of his eyes were looking upward at the fragmented remains of the deorbiter mass, Otis. They had saved a world, but at the expense of sentencing five innocent friends to a slow death.

  21:02:46 GMT TUESDAY 21 JUNE 2050

  The first warning Letter-Reader had of the catastrophe was the rumbling in the crust from the direction of the low hills nearby. His eye-wave pattern hesitated for a blink, then resumed as his brain-knot identified the sound as just another crustquake. Four of his non-pink eyes then returned to their task of reading the ancient scroll that lay unsprung on the crust. The scroll contained instructions for the operation of a magical machine that could talk to the stars in the sky. There were many words that Letter-Reader didn't know, but he hoped that by reading the scroll again and again they would become clear.

  The crustquake continued to rumble and seemed to be getting closer. The hunting reflexes built into Letter-Reader's pink and white speckled tread alerted his brain-knot, and he stopped reading to analyze the vibrations coming through the crust. It didn't sound like the approach of a wild Swift, so his herd of food Slinks were not in danger of attack. It was something new, however, and it was coming his way.

  Letter-Reader looked off in the direction that his tread had indicated. At first he saw nothing, then he noticed a disturbance in the crust. The disturbance was coming down the side of one of the nearby hills. He then looked up to see that one of the stars was falling from the sky. It was coming straight for him! His screaming tread carried him along as he and his herd ran away in panic.

  Steel-Slicer waited until Otis-Elevator had closed down the pumps on Eagle and had stabilized the energy accumulators.

  "Excellent landing," said Steel-Slicer. "How much energy do we have left in the accumulators?"

  "Only a quarter of what Cliff-Web had planned," Otis-Elevator replied. "But it should be enough to keep ship operations powered for a dozen turns."

  "We will need to have a new power generator up and operating by then," said Steel-Slicer. "Call the senior engineering staff up to the control deck. I will want your senior officers there, too. Place four spacers at the outer rail as lookouts. We are far from any city, but we did pass over someone on the way in." The crew deck on Eagle was compact, so it was not long before the senior staff gathered.

  "Now that we are on the crust, we spacers are out of a job until you engineers get this gravity catapult reactivated and bring down a ship for us to fly," said Steel-Sheer. "With Cliff-Web gone, I am going to assume the responsibility for management of the engineering contingent. I want Captain Otis-Elevator to assume responsibility for the spacer contingent. Unless one of the spacers has a technical ability that the engineers can use, their job is support, security, and interaction with the Egg cheela. It is a long way from flying about in ultrasophisticated spacecraft to preparing food and interacting with barbarians, but the sooner the engineers can rebuild technology in this Bright-Afflicted spot, the sooner we can be back into space."

  "We are all in this together," Otis-Elevator said. "My spacers will do anything that needs to be done."

  "It would help if we didn't have to use any energy for the food generators," said Steel-Slicer. "I noticed that we scattered a herd of animals as we landed. If you can form a food-gathering crew and find a few of those animals to feed us, your crew would not only help our energy crisis but be real heroes to a hungry group of engineers."

  "We will return shortly." Otis-Elevator lead his senior officers off.

  "Our first task will be to get power," Steel-Slicer told the engineers. "Who is in charge of the miniature power plant?"

  "I am," answered Engineer Power-Pack. "My team is loading the parts on the elevator n
ow."

  "I will go down with them," said Steel-Slicer. "What else will you need?"

  "A mass separator and a monopole generator," said Power-Pack. "We will need hundreds of meters of high-strength pipe to reach the neutron-rich magma below the crust."

  "They will be ready when you need them," Engineer Delta-Mass assured him. "Guaranteed leakless."

  "I think managing a Web Construction Company project is going to be the easiest job I ever had," Steel-Slicer said. "Let's ripple treads."

  "The elevator seems to be moving very slowly," said Steel-Slicer. "Is it because of the weight of the power plant parts?"

  "No," said Power-Pack. "Cliff-Web programmed the elevator controls for maximum energy extraction rather than maxi-

  mum safe descent speed. As we offload Eagle, the elevator motors will recharge the energy accumulators. Cliff-Web always liked to find ways of lowering the cost of projects."

  "In this case, he may have saved our hides," said Steel-Slicer. "He certainly was a remarkable engineer."

  "Yes, he was," Power-Pack agreed. The elevator deck remained silent for the rest of the ride down.

  When they reached the crust, Power-Pack slid aside the low gate and moved back. Steel-Slicer paused, then glided off onto the crust of Egg.

  "I have returned," Admiral Steel-Slicer declared softly into the warm, yellow-white crust. He paused as the others flowed off the elevator to surround him on all sides, awed by their return to their homeland. Then he spoke.

  "Call me Admiral Steel-Slicer no longer," he said. "I used to be called Star-Glider, but from now on call me Crust-Crawler. For I am tired of space, and I am tired of rejuvenations. I shall stay here until I flow."

  Letter-Reader was tending one of his remaining food Slinks, which had been acting sick. He pulled in his normal, dark red eyes and allowed only his three pink eyes to scan the creature. The ultra-red glow from one side of the food Slink indicated a problem. Thankful that his speckle-vision had saved another of the herd, he held it down, reached into one of its feeding pouches, and took out a number of small pebbles that the stupid creature had mistaken for ground nuts. Then he set the food Slink back to grazing.