Saturn Rukh (10 page)

“I’d better switch targets then,” said Sandra. “Saturn will have to wait. Rotate us around so I can see the rings, Rod.”

Rod put his hand in the controller under his console and twisted the joyball inside. The capsule rotated until the telescope peering out the vacuum port in the engineering sector was pointed downward toward the rings. They were nearly fully illuminated by the Sun and quite bright. The enlarged telescope image filled Sandra’s holoviewport with a multitude of arcs. For the next two hours Sandra took alternate shots of the E ring arcs and Saturn features. She also picked up some north pole images of Dione, Telesto, Enceladus, and Mimas, and an excellent shot of the braided F ring. They then started in over the brighter A, B, and C rings that were the only ones known to the ancient astronomers.

“Looks like the grooves on a phonograph record to me,” said Rod, looking over Sandra’s shoulder.

“We still don’t know why they stay so distinct,” said Sandra. “One would think over the millions of years they have been in existence they would have smoothed out more. Some people think there are lots of small ‘shepherding’ moons keeping the ringlets from spreading—I’m hoping to catch some of them in these photos. Haven’t seen any yet, though.”

“It would be hard for our eyes to pick out a single speck in all that clutter,” said Dan, peering at the rings passing under them through the biviewer. At the speed
Sexdent
was traveling, they passed over each of the main rings in a few minutes, so Sandra only took single, high-contrast, black-and-white images of each view.

“A ‘spoke’ is starting in the B ring,” Dan warned.

Sandra quickly shifted the magnification of the telescope from a close-up view of the ringlets to a wide-angle view that covered all the B ring and part of the A and C rings. As she took shot after shot, the single dark spoke overlaid on the whiter reflectance of the bright B ring was joined by other spokes.

“What’s the radio spectrum look like, Jeeves?” asked Dan, looking ahead of their path at the C ring to see if there were any targets there for Sandra.

“There are sharp bursts of noise—some of them correlated with the appearance of the spokes,” replied Jeeves.

“That’ll give the planetologists back home something to work on,” said Sandra, keeping the telescope busy as they sped over the rings toward the giant planet. As they passed over the almost invisible D ring, Rod called a halt.

“That’s it,” he said. “Only fifteen minutes left before our first big burn. It’ll be at three gees, so everybody put away all loose gear and strap into your couches.”

Soon everyone was at their stations, lying in a circle on the control deck on the padded frames, heads toward the center. Rod, Chastity, and Seichi were under the holoviewports of their respective stations, while their control consoles had been dropped down so they could operate them from their supine positions. The other three, their couches placed in between those of the flight crew, had their choice of holoviewports to look at.

Right now the holoviewports were showing a picture of the Space Unlimited Mission Control Center. In addition to the three constantly occupied consoles for crew communication, vehicle telemetry, and science data handling, there were two other consoles active, one controlling secondary comm links through large dishes on Earth, Luna, Mars, and deep space spacecraft. They would focus their antennas on Saturn during the upcoming maneuver to enable communication to be maintained despite the fact that
Sexdent
would be going behind Saturn. The other console was devoted solely to monitoring the performance of the twelve main engines—not that if anything went wrong the person at the console could do anything about it, but to have the failure data to avoid failures of those engine types in the future. The CrewComm was interrogating the other consoles. “Science Data?” “Go.” “Telemetry?” “Go.” “Comm Links?” “Go.” “Main Engines?” “Go.”

CrewComm turned to look at the video camera.
“Sexdent.
Provided nothing bad happens up there in the next seventy-five minutes, you are ‘Go’ for the mission.” The view of the Control Center disappeared and its place was taken by the flattened orange globe of Saturn and its brilliant white rings. Rod kept the nose of the capsule pointing at Saturn so they could all watch as the giant planet loomed to fill the sky. They were heading for a point on the equator of the planet just below the ring plane.

“Sure is big,” said Pete, impressed.

“Look at that white cloud,” said Sandra, pulling her arm out of its restraint to point at a cyclonic cloud feature as big as a continent on Earth. “It looks like a giant bird.”

A black arc began to creep across the image of Saturn from one viewport to the next.

“Here comes the terminator,” said Rod. “Line us up for perigee burn, Chass.”

Chastity twisted the joyball in her controller until the capsule was facing backward along their direction of motion. Two of the viewports now had rapidly rising images of Saturn in them, while the other one faced the rapidly shrinking ring arc that stretched diagonally across the window.

“Two minutes to go,” said Rod. “Ignite when ready.”

They were facing the Sun, which had been a continuously visible reference point in their sky for the past year. They watched the bright spot of light approach closer and closer to the rapidly narrowing fingernail slice of orange that was the limb of Saturn. Suddenly the Sun was gone and they were flying through pitch-black space, illuminated only by the light from the rapidly thinning arc of rings in the outer-facing viewport.

Just before they plunged into darkness, Chastity pulled up on the joyball. They were pushed into their couches as the twelve engines in the rendezvous stage roared into life, the reddish-purple metahelium plasma flame coming from the rear of the spacecraft brightly illuminating the clouds only a few tens of kilometers below.

~ * ~

Petra had just started the long climb upward with the flock. She opened wide the maws on each side of Petru’s keel, mouth-feathers oriented to allow maximum flow of the warm thick air. She closed the now-full maws of the giant body and squeezed hard. A ripple pulse passed down the tubes along the sides of the keel, pushing the air at higher and higher speeds until it jetted out the rear, driving the body of the giant bird higher. As one part of Petra’s mind continued to direct Petru through the mechanical motions of the climb, the rest of her mind was looking upward to the heavens through her giant single eye. Bright had set below the western clouds and although stars could be seen between the breaks in the clouds above them, the cloud breaks were few and small in size. This would not be a good night for observation of the stars, so Petra joined in the gossip of the flock as they climbed.

“Ketra! Watch where you’re going!”

“Sorry ... Ketro swallowed a slimswimmer the wrong way during yesterday’s hunt and Ketru has a sore left maw ... left airtube sometimes halts in midpulse.”

Suddenly a bright light appeared in the sky.

“What is
that?“
asked Hakra.

“Maybe it is Bright, rising again ...” said Falra.

Petra looked to see what was causing the commotion in the flock. Streaking high above them was a bright light behind the clouds. Having memorized many facts about the lights in the sky she had learned from Elders, Petra knew that Bright was not rising again. Besides, not only was the light in the sky too bright to be the Godstar Bright, the color of the light was wrong. Instead of the yellowish-white color of Bright, this rapidly moving glow was reddish-purple in color.

“It’s just a meteor,” said Petra, to reassure the rest of the flock.

“The Ancients say that meteors can hurt you,” said Conra. “Is it getting any closer?”

But as the glow continued and moved off to the southeast, Petra began to realize that this was not a meteor, but something else—something new in the sky.

“It is going away,” said Petra. “There is no more danger.”

The flock continued its climb, its gossip enriched by the recent event. Petra didn’t join in as she added the information she had collected to her memory. She would visit the astronomers in the neighboring flocks during the next posthunt play period and see if they had been able to see the long-lasting purple light better than she had. Her mind couldn’t help but speculate on what it might have been. If it was not a meteor, perhaps it was a comet. Comets grew bright and developed a long tail as they passed around the Godstar Bright. Perhaps this was a comet that grew bright as it passed around Air. Then again, it might be a strange form of lightning. Lightning sometimes gave off blue and purple light, but lightning moved very fast, while this purple light, although it moved rapidly through the skies, was nowhere near as fast as lightning. Petra couldn’t think of anything else that might have been the cause.

~ * ~

After ten minutes, Rod announced through clenched teeth, “Only a half minute more.”

The roaring finally stopped, and they went from three gees to free fall.

“Trajectory looks good,” said Chastity, reading her pilot screen. “We took off nineteen klecs and are on track for Titan. We should get there in three days.”

“If you wouldn’t mind, Chastity,” said Sandra, “I’d appreciate it if you would rotate us so our telescope port is pointing north so I can get some shots of the underside of the rings. We’ve already passed under most of the D ring, and the C ring is coming up.”

“Okay,” said Chastity, rotating
Sexdent
until the telescope had a good view of the rings above them.

“I see some spokes coming up on the B ring,” said Dan, who had unlatched the biviewer and was spotting for Sandra again. “From the underside, the spokes show up brighter than the rings rather than darker.”

“Forward scattering,” said Sandra as she started collecting images. “The spokes are generated by small charged dust particles kicked loose from the bigger rocks by electrical currents. The dust particles scatter light better than the big chunks.”

~ * ~

As soon as they cleared the backside of Saturn and could see Earth again, Jeeves set up a direct comm link to Earth through the high data rate laser communicator dishes. There were three dishes, each thirty centimeters in diameter, spaced 120 degrees around the ship so that one of them always had Earth in sight. The minute the receivers were turned on, they found a message streaming through space to them. It was from the Mission Control Center, congratulating them on their successful perigee burn, which had happened over an hour ago. Bemused, Rod responded. “Engines worked fine. We’re on our way to Titan.”

~ * ~

Three days later, they met Titan out at its orbit.

“Still just a featureless brown ball of smog,” said Dan dejectedly as he scanned Titan through the biviewer.

“You’re just looking in the wrong frequency band,” said Sandra. “Both microwaves and near infrared can penetrate the smog clouds. Why don’t you put down that biviewer and help me. You take the near-infrared telescope, while I set up the radar imager.”

A few hours later they had moderately good images of the visually hidden surface of Saturn’s largest moon—bigger than the planet Mercury and second only to Jupiter’s moon Ganymede in size.

“Here it is—Titan undressed,” said Sandra, as she gave the rest of the crew a tour of the orange smog moon on her holoviewport. “Since Titan is tidally locked to Saturn, it has six poles—the usual north and south spin poles, the inner pole that always faces Saturn, the outer pole that always faces away from Saturn, the leading pole that faces the direction of Titan’s motion in its orbit, and the trailing pole on the opposite side of that.”

She switched the holoviewport above the engineering console to show the infrared image of one side of Titan. It had a large dark splotch in the center that covered nearly the whole hemisphere.

“This is the trailing pole image,” she said. “The dark regions are deposits of hydrocarbons all the way from simple compounds like methane—C-H-four—to complex carbon-chain hydrocarbons like oil and tar. Right here is a small ocean—mostly methane—but probably containing ethane and other stuff dissolved in it.”

“How do you know it’s methane?” asked Chastity.

“Because Titan’s atmosphere still has lots of methane in it. It’s ninety-five percent nitrogen and argon, and five percent methane. Since methane is easily broken up by sunlight to carbon and hydrogen, and hydrogen is easily lost to space, there must be a reservoir of methane on Titan’s surface to keep the atmosphere replenished—in this case the reservoir is a small ocean. Besides, the surface pressure and temperature of one-and-a-half bars at ninety-four kelvin are in the range where methane and ethane are liquids.” She switched to another view. This infrared image had a bright patch in it. “This is the leading pole image,” she said. “That bright spot is a high-elevation continent of frozen water and ammonia ice sticking up out of the hydrocarbon-covered plains.”

“Do you think there may exist lifeforms there?” asked Seichi.

“The landers haven’t seen anything on Titan,” replied Sandra. “Although there are a lot of hydrocarbons there, and even an ocean to get life started, the temperatures are probably too low for the chemical reactions to proceed at the necessary speeds. It’s different on Saturn, where the temperatures get up to room temperature and higher. We
know
there are lifeforms
there
—and soon we’ll have some on board to look at!”