The Sails of Tau Ceti (12 page)

“You can’t just fall in love the way you order a new air bottle!”

“Sure, you can. The human psyche is a wonderful instrument. Provide the proper stimulus and you always get the proper response.”

“What about after the mission?”

“Then we fall
out
of love with each other, if that is what we want. I start slurping my morning coffee; you start leaving your underwear hanging in the sanitary cubicle. Inside a week, we won’t remember what the attraction was.”

“You’re serious, aren’t you?”

“Of course,” he said. “Take a survey of old married people and see how many of them were in love when they first wed. I think you’ll be surprised.”

“How do we go about falling in love?”

“Dinner in my cabin with the lights turned low for starters. I have a bottle of wine that I was saving for when we get our first good look at the alien starship. We will crack it open and drink to romance. Afterwards, we’ll sit close together, watch a holo, and you can pretend to laugh at my jokes.”

“I’m game if you are.”

He bowed as low as he was able from his sitting position. “May I call on milady for drinks this evening?”

She grinned. “I doubt I will be very good company. I have to do a complete software scan.”

“Good point. I expect to be somewhat busy myself. What do you say to tomorrow night?”

“It’s a date.”

“And to seal the bargain?”

She floated toward him and pressed her lips lightly to his. Despite their best efforts, the kiss lacked ardor. When they parted, Van Zandt sighed.

“‘The spirit is willing, but the flesh is weak.’ We’ll try again later when we’re both more rested from the cold sleep.”

“You’re the captain,” Tory replied as she moved to the other acceleration couch. She was both disappointed and exhilarated. It was a decidedly odd frame of mind.

CHAPTER 9

“Bring the telescope to full magnification,” Kit Claridge ordered.

Beside her, Tory moved to comply. The two of them were running an observation program ordered by the scientists on Earth. They were photographing the region around the light sail in the ultraviolet wavelengths to visually map the river of plasma that flowed toward the alien craft. There ought to be visible effects where the inbound and outbound plasma streams interpenetrated. With luck, the scientists might be able to estimate of how far in front of the light sail the starship was suspended.

“Full mag,” Tory reported. “No problems encountered.”

“Right. Begin the observation cycle.”

It had taken six weeks for
Starhopper
to climb to four percent of light speed, and twice that long to back down again. First, they had to halt their outbound flight, and then accelerate back toward the sun as the light sail overtook them.
Austria
had reached its maximum retreat from Sol at 10:34 hours on May 1, 2242, when it achieved an “altitude” of 650.378 light hours. Garth celebrated the occasion by sending a message to Earth claiming the system record for a manned spacecraft. It was indicative of the distances involved that the message would require 27 days to reach Earth.

The two women sat back in their acceleration couches and regarded the starfield in the middle of the screen. The task of mapping the energetic hydrogen was made more difficult by the softly glowing fog that hugged the screen’s lower edge. This was spillover from
Starhopper
’s own plasma drive. It would continue to degrade their long-range sensors until they pulled alongside the alien.

A week earlier, Kit had attempted to perform the same experiment. The sail had just begun to show a disk and the research teams on Earth had asked that they map the plasma flow to get a better idea of the power the aliens were pumping into the interstellar medium. Midway through the hour-long observation, something had gone wrong with the telescope. An unexplained glitch had overloaded the delicate sensors, ruining the data. After reviewing the recordings of that session, Kit had requested that Tory monitor the telescope with her implant to ensure that the instrument was working properly.

“Scanners are recording normally,” Tory reported.

Kit shrugged. “I can’t figure it out then. Maybe I flubbed a switch setting.”

“I’ll watch for a bit more before going back to my other duties.”

“Thanks. I can use the company. I hardly have time to go to the head, let alone engage in some good old fashioned human interaction.”

“I know what you mean.”

With the light sail so close, the relatively relaxed work schedule of the initial approach had suddenly gone by the boards. Demands for observations were rising asymptotically. It seemed as though every analyst on Earth had suddenly decided that he must have new data soonest. The communications delay did not help. With nearly two months between request and response, they were likely to get a dozen follow-up requests for the same experiment.

“What was that?”

“What was what?” Tory asked. She had been concentrating on following the software routines and had not been looking at the screen.

“I saw a flash.”

“Where?”

“The light sail.”

“Are you sure?”

Kit nodded. “It was like a beacon. The image brightened for an instant, and then was gone.”

Tory watched for a dozen seconds, but saw nothing. She was about to put it down to overwork on Kit’s part when it happened again. The flash was too quick to properly register on the human retina, but it seemed to originate from the center of the light sail.

They watched intently until the flash reappeared thirty seconds later. Tory noted that the telescope was set to study the middle ultraviolet, which meant that whatever was causing the flash was invisible to the unaided human eye.

They watched the phenomenon for several more cycles. It appeared and disappeared at random. The shortest interval between flashes was ten seconds, the longest, a minute and a half.

“What do you think? Are they trying to communicate with us?”

“Comm laser?” Tory responded. “It’s possible. They may have trouble locking onto us at this range. They must know we are here. They’ve been staring directly up our drive flare for eleven weeks now.”

“Weapon?”

That, too, was a possibility. Tory remembered how paranoid it had seemed when they had insisted on not including a comm laser on
Austria
because it would look too much like a weapon. Suddenly, it did not seem paranoid at all.

“Of course!”

“What?”

Tory indicated the telescope controls with a sweeping gesture. “What is it we are attempting to do here?”

“We’re mapping the ionized hydrogen cloud … oh!”

“Correct. We are coming into range of the laser that is doing the ionizing! Every time it scans across us, we see a flash. I’ll bet the wavelength is precisely the one that is most efficient at ionizing interstellar hydrogen.”

“No bet. You’d better notify the captain.”

#

Garth Van Zandt stared at the recording of the light sail and waited for the flash. They had slowed the image down a hundred times. Even then, it was amazing how quickly the sudden brightness came and went. It was a testimonial to the acuity of the ship’s telescope and the human eye that the two women had seen it at all.

“Spectrum?”

“Pure monochromatic light,” Kit replied, reading off the wavelength.

The captain grunted his assent. “You nailed it, Tory. It is definitely their ionization laser. We’d best get this news off to Earth.”

“I’ve already done that. I’m collecting data on power now.”

He nodded. “That ought to tell us how close we can approach without getting fried.”

Tory frowned. “I hadn’t thought of that. Do you really think it could be dangerous?”

“Depends on how tightly the aliens have it focused. If we knew the scan rate, we could use the duration of the flash to compute the beam spread. In any event, if they are harvesting hydrogen from across as large a volume of space as we think, they are not using a flashlight.

“Why are the flashes so erratic?” Kit asked.

“The beam probably misses us on most passes,” Van Zandt responded. “We only see the flash when it scans directly over us.”

“Doesn’t that give us the information we need to compute the width of the beam?”

“Does it?”

“Sure,” Tory said. “We take the minimum interval between flashes and assume that is the result of our seeing two successive scans. Then we take the maximum interval and compute how many scans we missed. If we assume they scan the beam so that it completely fills the space in front of them, that tells us the maximum size of the beam at our distance from the alien. We then use that data to compute the beam spread.”

“Might work,” Garth agreed after several seconds. “I doubt it’s quite that easy, however. What if your min or max intervals between flashes change?”

“Then we recompute with the new data. Eventually we’ll converge on the real value.”

“All right, set it up.”

“Right!” Tory suddenly got that faraway look that told the others she had activated her implant. To all outward appearances, she had left the room.

“How are we going to approach the alien if the laser turns out to be dangerous?” Kit asked.

Garth stroked his chin. “That could be a problem. Still, I doubt they are scanning all of circum-ambient space. That would be inefficient. If I were designing their system, I would limit the laser to the volume from which I could sweep up hydrogen. No sense in wasting power on hydrogen they have no hope of harvesting.”

“What does that mean?”

“No matter how strong a field they’re using the attract the charged ions with, there’s a limit to how far they can pull them in at their current speed. The laser is probably confined to a narrow cone directly along their line of flight. If we move to the side, we should be able to get out of its focus. Once Tory tells us the scan rate and the width of the beam, we’ll be able to compute the size of the cone they are using … I hope.”

“And all we need do is steer clear?”

“That’s the idea.”

“What if they can point the laser like a weapon?”

Garth’s shrug was Gallic in its expressiveness. “That’s what we’re here to find out, isn’t it?”

#

No longer was the light sail a distant point of light against the black velvet of the firmament. Over the last several days the alien construct had grown from a tiny disk, to a lighted moon, to an entire world that seemed to hover just beyond the reach of
Starhopper
’s drive flare. Tory estimated the light sail’s diameter at 19,987 kilometers from edge to edge — three times the diameter of Mars and two-thirds larger than Earth. As for the sail’s overall mass, she could only guess. The true scale of the alien artifact was just beginning to register on her.

“Give me a reading on the plasma density,” Van Zandt ordered.

“No change in the last hour.”

Austria
was submerged in the river of ionized hydrogen that was flowing out of space and onto the surface of the light sail. The plasma density was high enough to affect the focus of the magnetic field in their nozzle assembly. Of late, glowing coronas had begun to appear at various points along the booster. Worst of all, the ion fog had dramatically increased the glare produced by
Starhopper
’s own fountain of plasma. The suffused radiance of their drive flare had effectively blinded many of their most sensitive instruments.

“Keep monitoring. Advise me the instant there is any change plus or minus.”

“Aye, Captain.”

Except for hurried breaks for personal hygiene, neither Garth nor Tory had left their stations for the past three days. They ate and slept in rotation, with one of them awake and manning the controls always. Nor were there any of the soft touches or words of endearment they shared off duty. When on the bridge, the captain and his chief engineer were all business. Kit Claridge and Eli Guttieriz were likewise unable to pursue their personal relationship. They were kept busy fulfilling the insatiable demands of the Earthside scientists for observations during the approach. For the first time in the voyage, the communications delay worked in their favor. Had the scientists on Earth been able to observe the approach in real time, their demands would have quickly escalated to the point of overload. As it was, they had been forced to preprogram all of their observation requests on Earth a month, and would not receive the results until a month after
Starhopper
rendezvoused with the alien.

Tory let her attention turn back to the light sail. They were fifty thousand kilometers in front of the light sail, with a closing rate that was little more than an interplanetary walk. They were seven minutes from engine shutdown and had begun a search for the starship that must be somewhere in front of the sail. At this range, however, looking for the manned craft was very much like looking for the proverbial needle in a haystack.

The pattern of light and dark that had been discernable for weeks now stood out in stark contrast on the viewscreen. The sail was billowed out as though filled with an invisible wind — as indeed, it was. Where some parts reflected the blackness of space, others concentrated the ion glow. The two effects combined to produce moving spokes of light as the sail rotated slowly. If God were ever to build a kaleidoscope for His own use, then it would surely resemble the light sail.

By concentrating, it was possible to make out the points where individual shroud lines attached to the main body of the sail. The attach points were arranged in twelve concentric rings, with shroud lines numbering over a thousand. The lines themselves were invisible, but their arrangement revealed a great deal about the sail’s construction. Whatever material made up the sail, its overall strength was little better than tissue paper. This result surprised Tory until she remembered that tissue paper was many thousands of times thicker than even a human light sail. No matter what reasonable thickness she assumed for the sail, the resulting requirement for tensile strength was far beyond anything known to human science.

Of the ionization laser, there was no sign. It had been four days since
Austria
had last seen the ultraviolet flash. As Garth had surmised, the laser scanned a narrow cone lying directly along the light sail’s flight path. The aliens were not wasting their precious energy on those portions of the interstellar medium beyond the reach of their electrostatic particle scoop. Once
Austria
left its scan cone, the laser had appeared to go dark.