She resumed her script. “When tipped such that the instrument arm reaches its highest position, the GBT stands taller than the Statue of Liberty. This is the world’s largest fully steerable radio telescope.”
Hand to his forehead, shading his eyes, Marcus countered, “Surely Arecibo is bigger.”
Because everyone knew the observatory at Arecibo, Puerto Rico. Filmmakers loved it. The first time she remembered seeing the Arecibo dish was in some old James Bond flick. Golden Eye, maybe.
Arecibo’s dish was three hundred meters across, its aluminum panels suspended over a mesh of steel cables to form a single surface: way too massive to move. To aim the Arecibo telescope—to the extent it could be aimed—you positioned its suspended instrumentation module using the cables that spanned the dish. None of which mattered: if she failed, Arecibo would face the same problems as Green Bank.
Valerie limited herself to, “Bigger, but not fully steerable.” She pointed at the GBT’s base, where the mammoth wheels engaged the circular steel track. “As opposed to our big scope. This whole structure can rotate up to forty degrees a minute, versus one-fourth degree per minute needed to keep pace with Earth’s rotation. The dish can tip up and down at as much as twenty degrees per minute. That instrument turret at the end of the arm holds up to eight independent instrument modules, each—”
“Back up,” Marcus said. “Those tipping and turning rates. You’re telling me that the GBT can track planets, asteroids, even close-orbiting satellites. Stars and galaxies only move with the Earth’s rotation.” She must have looked surprised because he added, “Remember who I work for?”
“Right. And sorry.”
“Except asteroids and most planets don’t emit radio waves. In the middle of the quiet zone, where my cell phone has no service and NRAO won’t even permit digital cameras up close, I can’t believe the observatory is pumping out radar pulses so you can read the echoes.”
He was quick, which was promising, and he seemed engaged in what she’d had to show him. But around the eyes she saw a touch of … something. Suspicion? Was she that transparent, or was it something else?
“You’re correct,” she said. “Arecibo transmits and Green Bank reads the faint echoes. We could transmit ourselves”—she pointed up at the instrumentation arm—“by replacing one of the receiver modules with a transmitter, but that would hardly be radio quiet. My work involves radar mapping of Titan, and we partner with Arecibo to do it.”
“Titan? Just how sensitive is this scope?”
“If there were a cell phone on Titan, with the GBT”—and lots of post-processing—“I could listen to the call.” Barring other complications, and that topic was coming. “We need to move along, Marcus. The weekly science lunch is not to be missed.”
Especially because you are on deck.
* * *
Patrick Burkhalter toted his cafeteria tray to the residence hall’s second floor, where he found the social lounge half filled. Many of his colleagues were already seated and eating. Others surrounded Valerie Clayburn and her guest, meal trays in hand, intercepted before they could find a table. With maybe eight thousand people in the entire county, everyone welcomed new faces. But visitors and outsiders comprised very different categories, and after eight years here Patrick remained an outsider.
“Hey,” he offered as he took an empty seat. Tamara Miller glanced his way, nodded, and went back to her conversation with Liam Harris. Something about intergalactic dust.
Patrick went to work on his country-fried steak, mashed potatoes, and gravy. His choices would do nothing for his waistline or his cholesterol, but who did he have to impress?
Or to live for? That was a thought depressing enough to make him set down his fork.
Their guest got perhaps two minutes with his lunch before Valerie began tapping her water glass with a butter knife. “Hi, everyone. We have a visitor, as you may have noticed.”
Not to mention that she had put out the word to make sure the tech staff all came today. Would she get the outcome for which she so obviously schemed? In Patrick’s experience, manipulating scientists and engineers worked about as well as herding cats.
“Hello,” the chorus rang out raggedly, from around the collection of short, narrow tables arrayed in a U.
Valerie said, “Our visitor, Marcus Judson, works at NASA Goddard on the demonstration powersat project. I’m hoping he’ll tell us about it.”
Patrick refocused on his lunch while others murmured their encouragement.
Judson kept his response short, and Patrick approved. You didn’t know you were today’s featured attraction, did you?
“So what do you think, folks?” Valerie prompted. “How will powersats affect us here?”
And the games began.
“A powersat is a huge noise generator,” Aaron Friedman said. “And because it’s sky-based, that’s noise from which we can’t hide.”
“The power beam is focused.” Judson slid away his tray, the meal all but untouched, clearly perceptive enough to see what was coming. “The downlink won’t come anywhere near here.”
“Doesn’t matter,” Aaron persisted. “Well, aiming will help, but not enough. The satellite shapes the beam with phased-array techniques, right? So there are unavoidable side lobes to the main beam. That’s basic math. Even sixty dB down, there’ll be a lot of noise.”
Engineers and astronomers set aside lunches to argue about phased arrays: their pointing accuracy and failure modes, the frequency distributions apt to show up within the noise, and whether sixty decibels was the expected attenuation for a side lobe. Of course even sixty decibels down from one gigawatt left a kilowatt of noise.
Judson kept thanking people for their comments. Mostly he let the staff argue among themselves, jotting notes on paper napkins—and looking ticked off.
This was not a mugging, exactly. More like an intervention, or maybe an inquisition. When Patrick tried to catch Valerie’s eye, she looked away.
Patrick knew all about inquisitions by the tech staff. That had been his introduction to Green Bank, too, if for a different reason. Judson would go home with only bad memories to show for the day. Whereas he …
He still bore the scars. Patrick was more than qualified to coordinate routine maintenance and teach visiting astronomers to operate the gear, so it hadn’t been entirely a pity appointment. More like an I’ll owe you one arrangement between execs at the apex of Big Science.
After the Jules Verne probe went missing, JPL wanted Patrick gone. NASA did, too, but even more, they wanted to put a halt to the embarrassing publicity. No matter what anyone suspected, they could only prove that he had cut procedural corners to upload an emergency maneuver. That the distant probe went silent days later could have been pure coincidence.
And so Patrick had made clear what would keep him from giving interviews and suing for wrongful termination. He required ongoing access to a big dish—somewhere.
Without too much torture of the English language, Green Bank was somewhere.
And so he went in one not-so-easy step from the principal investigator of a major interplanetary probe to lowly observatory staffer. Training and maintenance offered plenty of opportunities to use radio telescopes without grant applications sure to be rejected.
He used the big dishes every chance he could get.
After the divorce—no way would Anna move here from Pasadena—what else did he have to do?
He had sworn to Anna that things would turn out all right. That maybe this had happened for a good reason. He would not have trusted him, either, especially given how little he had been able to explain, but it still hurt that she hadn’t. More than anything, he missed the kids. He wondered if Rob and Clarissa would ever understand, or forgive him for the divorce.
When Patrick tuned back into the present, Judson remained in the hot seat. Only the objections varied: from powersats, miles across, getting in the way of observations, to the heat they would reradiate as infrared, to minutiae of
RF interference. Some people argued for the joy of arguing. Par for the course here, but Judson could not know that.
Along the way, an admin slipped into the lounge and handed Valerie a folded sheet of paper. Another joy of life in the quiet zone: runners instead of cell phones. Valerie grimaced at whatever she found written, dashed off her own note and handed it to Judson, then rushed off.
By the time the hyperbole reached, “Powersats will mean the end of astronomy until”—yeah, right!—“someone builds an observatory on the far side of the moon,” Patrick had had enough.
“There’s more to life than astronomy,” he snorted. Too bad Valerie had left. If anyone needed the reminder, she did. But for Simon, she might never go home. “And life takes power, people. Lots and lots of power.”
Turning, Tamara gave Patrick an Et tu, Brute? stare, but from across the room a couple of engineers nodded.
“We learned to live with DirecTV,” Ernesto Perez conceded.
To which someone snapped, “Yeah, by giving up listening on those frequencies.”
Rekindling the debate, from which it took the tech director noisily sliding back her chair to bring a halt.
* * *
At least, Marcus thought, tucking his notes from the lunch into his shirt pocket, one secret of the universe had been revealed. Town meetings were not the worst way to spend a day.
If he had correctly parsed Valerie’s scrawl, she was retrieving a sick kid from school and going home for the rest of the afternoon. One scribble might have said “single mom,” to explain her disappearance. It was too bad about her son, but Marcus was happy to make a quick getaway.
Only driving home, as much as he tried to enjoy the Appalachian scenery, he couldn’t. Ellen’s recent rebuke kept nagging at him: Have you considered the possibility someone else might know something?
If he could get past Valerie bushwhacking him, she had given him a lot to ponder.
Wednesday, April 19
Marcus poked at a telecomm console, setting parameters for the upcoming conference call, and thinking: All meetings are not created equal. He was in a mundane conference room at Goddard, deep within suburban Maryland, but this call was out of this world.
Whatever grief the week might bring him, the progress review reminded him why everything else was worth it.
Landscape undulated over the conference table, sliding past as a distant camera swiveled on its post. Somewhere behind the camera, the full moon was about to set; Phoebe’s hills and structures cast long, knife-edged shadows. To his right, in the tourist-bot preserve, the Grand Chasm gaped: a vast, inky blackness. The dazzling “star” just above the eerily close horizon was The Space Place, almost two hundred miles ahead of Phoebe in its orbit.
Ellen limped into the telecomm room, bearing Starbucks. Despite physical therapy, her leg kept bothering her. She set a cardboard cup on the table beside him.
“Thanks,” he said, concentrating on the final link left to configure. “That said, you have no respect for tradition.”
She laughed. “Okay, who confirmed for today’s session?”
He gestured at the holo. “The usual folks on the far end, though Darlene Stryker is at the powersat. She’ll call in from there.”
“How far is the far end today?”
As distant as it could be. “As the neutrino flies”—right through the Earth, without noticing—“it’s about thirteen thousand miles. Relayed through two geosynch comsats and then down to Phoebe, call it a half second.”
She closed the door and settled into a chair. “Who’s joining from on the ground?”
“Phil and Bethany.” Phil Majeski was the prime contractor’s program manager. Bethany Taylor was Phil’s chief engineer. Both disdained SETA contractors. “Phil’s netting in from corporate. Bethany called to say she’s stuck at a subcontractor’s facility. Resetter picketing, unrelated to us, something about shale-oil gasification in Wyoming. I’m linking her in now.” Marcus waved a wireless key fob at the sensor in the comm console. The authentication LED blinked green. “Ready.”
“Let’s go.”
Marcus shrank the Phoebe image to one-fourth size, then switched views from the surface to the base’s little common room, where three men sat waiting. As they and Ellen swapped greetings, Marcus connected the other locations.
“Everyone have the agenda?” Ellen asked. She started through her list.
The comm console took notes, but speech-recognition software glitched under the best of circumstances. These weren’t. Merely this many people in one conversation sometimes confused the software. With the comm delay between Earth and Phoebe, people spoke over each other as often as not, and echo suppression was less than perfect. Noise suppression filtered out the drone of Phoebe’s ventilation fans, but not the random clatters of—well, Marcus did not always know what.
So Marcus took notes, too.
Lots of notes. Hydroponics yields in Phoebe’s still experimental gardens. Performance data on the thrusters that would slowly lift the powersat, its construction now almost complete, to its operational orbit. Final integration tests on the microwave transmission arrays. Production data on Phoebe’s automated factories, churning out solar cells (and in smaller quantities, other electronics), structural beams, and water and oxygen for the construction crew. Defect and repair rates. Assembly anecdotes—but not many, the process having become routine. Assembly statistics.
PS-1 had just topped two million pounds! How amazing was that? The late, unlamented International Space Station had massed only about one-third as much, and its on-orbit assembly had required more than a decade. But the ISS had been lugged up to orbit piece by piece, battling Earth’s gravity all the way—for more than a thousand dollars for every pound. For a powersat fabricated on Earth, launch costs alone would rival construction costs for a coal power plant of equivalent capacity.
But most of PS-1’s ingredients came from Phoebe’s mines. And that was why—while there would never be another big tin-can space station—tens of powersats would join PS-1. Even combined, all those powersats would scarcely touch Phoebe’s trillion-ton mass.
Motion in one of the four holos kept drawing his eye. Darlene Stryker, in her skintight counterpressure suit. She floated above the vast plain of the powersat, the nearest safety-and-inspection camera following her as she drifted at the end of her tether. As the camera tracked her, coworkers—most many-tentacled robots; one human and spacesuited like her—passed in and out of the background. He did not see any of the hoppers that shuttled workers the fifty miles from Phoebe to the construction site on the powersat.
Two million pounds was an abstraction. But two miles square, more or less: that was real. That he could feel. Marcus admired the plain of solar cells aglitter in the moonlight. PS-1 seemed to stretch on and on forever.
“Okay,” Ellen said at last. “Good session, folks. Bethany, I’ll look forward to your update on getting the backup water recycling system back to nominal. For next week’s meeting?”
“No problem,” Bethany said. “Chances are you’ll have something in your e-mail by the day after tomorrow.”
“Excellent.” Ellen stood. “That should do it, then.”
“One thing,” Marcus said. The words just popped out. Something about PS-1 stretching into the distance. Something about defects, and big engineering, and his subconscious at work.
Phil Majeski scowled, putting his whole face to work: brow furrowed, eyes narrowed, lips pursed. Phil was no fan of support contractors.
“What is it, Marcus?” Ellen sounded surprised. He usually held any comments until after the meeting.
What indeed? Big engineering. What else was big? The solar farm he and Ellen had toured. Square miles there, too, of solar cells, plus the rectifying antennas newly added to receive the microwave downlink from PS-1. The Green Bank Telescope, the collection area of its dish a “mere” two-plus acres. Eavesdropping on phone calls out near Saturn.
Then he had it: the flip side of the powersat,
from this vantage unseen. The microwave transmission arrays. No one had ever deployed such a large phased-array transmitter, whether using solid-state masers or tube-based amplifiers coupled to microwave antennas. Nothing ever built even came close. PS-1 incorporated both type arrays, each in several design variations. The separate arrays would operate standalone or in unison, allowing side-by-side comparisons. In every case, many thousands of transmitters …
“The failure rates on the klystrons and masers?” Marcus began cautiously.
“What about them?” Bethany said. “We covered that. They’re all testing well within contract specs.”
“Understood. But when won’t at least one tube or maser be out of spec? Pumping out microwaves at unintended frequencies?” Because the focused, steerable power beam resulted from exactly controlling—individually and in real time—the many thousand transmitters. The math of phased arrays was a thing of beauty, the choreography of constructive and destructive interference among transmitters. Only waves at the wrong frequency would not interfere properly, would not aggregate into a controlled beam. Wrong frequencies were just … noise. “A single misbehaving klystron—out of thousands—is like a whole TV satellite transmitting on an unauthorized frequency.”
“Which is why,” Bethany snapped, “when a klystron goes out of spec, we’ll power it down. Powersat-resident maintenance robots and spare parts, remember?”
And if, in the meanwhile, the interference obliterates an interstellar observation years in the planning, or the faint echoes of a radar beam bounced off Titan?
“Maybe the radio astronomers have a legitimate concern,” Marcus said. “How soon will PS-1 detect and adapt to an out-of-tolerance transmitter?”
“Soon enough,” Bethany came back, only without her usual cockiness.
Ellen heard the uncertainty, too. “As I recall, Kendricks signed up to a requirement to minimize RF interference with ground-based systems.”
“We all have a schedule requirement,” Phil rebutted. Schedule was the blunt instrument with which Congress beat up NASA, and NASA the contractor. But deadlines could work both ways. “Surely schedule takes precedence over hypothetical failure modes.”
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