Just one press of his controller and he could stop right here, go back.

He reached the center of the disc. An electric blue light bathed him. He leaned forward inside his stiff HUT unit, so he could look up.

The artifact had come to life. The electric blue light was glowing from the substance of the circle itself. He could see speckles in the light. Coherent, then. And when he looked down at his suit, he saw how the white fabric was crisscrossed by the passage of dozens of points of electric blue glow.

Lasers. Was he being scanned?

“This changes everything,” he said.

The blue light increased in intensity, until it blinded him. There was a single instant of pain—

Chapter 6

Transmission

“We think a Gaijin flower-ship is a variant of the old Bussard ramjet design,” Sally Brind said. She had spread a fold-up softscreen over one time-smoothed wall of Nemoto’s lunar cave. Now — Maura squinted to see — the screen filled up with antique design concepts: line images of gauzy, unlikely craft, obsessively labeled with captions and arrows. “It is a notion that goes back to the 1960s…”

Nemoto’s home — here on the Japanese Moon, deep in Farside — had turned out to be a crude, outmoded subsurface shack close to the infrared observatory where she’d made her first discovery of Gaijin activity in the belt. Here, it seemed, Nemoto had lived for the best part of two decades. Maura thought she couldn’t stand it for more than a couple of hours.

There wasn’t even anywhere to sit, aside from Nemoto’s low pallet, Maura had immediately noticed, and both Sally and Maura had carefully avoided that. Fortunately the Moon’s low gravity made the bare rock floor relatively forgiving, even for the thin flesh that now stretched over Maura’s fragile bones. There were some concessions to humanity — an ancient and worn scrap of tatami, a tokonoma alcove containing a jinja — a small, lightweight Shinto shrine. But most of the floor and wall space, even here in Nemoto’s living area, was taken up with science equipment: anonymous white boxes that might have been power sources or sensors or sample boxes, cables draped over the floor, a couple of small, old-fashioned softscreens.

As Sally spoke, Nemoto — thin, gaunt, eyes invisible within dark hollows — pottered about her own projects. Walking with tiny, cautious steps, she minutely adjusted her equipment — or, bizarrely, watered the small plants that flourished on brackets on the walls, bathed by light from bright halide lamps.

Still, the languid flow of the water from Nemoto’s can — great fat droplets oscillating as they descended toward the tiny green leaves — was oddly soothing.

Sally continued her analysis of the Gaijin’s putative technology. “The ramjet was always seen as one way to meet the challenge of interstellar journeys. The enormous distances even to the nearest stars would require an immense amount of fuel. With a ramjet, you don’t need to carry any fuel at all.

“Space, you see, isn’t empty. Even between the stars there are tenuous clouds of gas, mostly hydrogen. Bussard, the concept originator, proposed drawing in this gas, concentrating it, and pushing it into a fusion reaction — just as hydrogen is burned into helium at the heart of the Sun.

“The trouble is, those gas clouds are so thin your inlet scoop has to be gigantic. So Bussard suggested using magnetic fields to pull in gas from an immense volume, hundreds of thousands of kilometers around.”

She brought up another picture: an imaginary starship startlingly like a marine creature — a squid, perhaps, Maura thought — a cylindrical body with giant outreaching magnetic arms, preceded by darting shafts of light.

“The interstellar gas would first have to be electrically charged, to be deflected by the magnetic scoops. So you would pepper it with laser beams, as you see here, to heat it to a plasma, as hot as the surface of the Sun. It’s an exotic, difficult concept, but it’s still easier than hauling along all your fuel.”

“Except,” Nemoto murmured, laboring at her gadgets, “that it could never work.”

“Correct…”

Maura had been privy to similar breakdowns and extrapolations emanating from the Department of Defense and the U.S. Air and Space Force, and — given that Sally’s summary was based on no more than piecework by various space buff special-interest groups and NASA refugees in various corners of the Department of Agriculture — Maura thought it hung together pretty well.

The problem with Bussard’s design was that only a hundredth of all that incoming gas could actually be used as fuel. The rest would pile up before the accelerating craft, clogging its magnetic intakes; Bussard’s beautiful ship would expend so much energy pushing through this logjam it could never achieve the kind of speeds essential for interstellar flight.

Sally presented various developments of the basic proposal to get around this fundamental limitation. The most promising was called RAIR — pronounced “rare” — for Ram-Augmented Interstellar Rocket. Here, the intake of interstellar hydrogen would be greatly reduced, and would be used only to top up a store of hydrogen fuel the starship was already carrying. It was thought that the RAIR design could perform two or three times better than the Bussard system, and achieve perhaps 10 or 20 percent of the speed of light.

“And, as far as we can tell from the Bruno data,” Sally said, “that Gaijin flower-ship was pretty much a RAIR design: exotic-looking, but nothing we can’t comprehend. Bruno actually passed through what seemed to be a stream of exhaust, before it ceased to broadcast.” A nice euphemism, thought Maura, for was trapped and dismantled. “The exhaust was typical of products of a straightforward deuterium-helium-3 fusion reaction, of the type we’ve been able to achieve on Earth for some decades.”

Sally hesitated. She was a small woman, neat, earnest, troubled. “There are puzzles here. We can think of a dozen ways the Gaijin design could be improved — nothing that’s in our engineering grasp right now, but certainly nothing that’s beyond our physics. For instance the deuterium-helium fusion reaction is about as low-energy and clunky as you can get. There are much more productive alternatives, like reactions involving boron or lithium. I think I always imagined that when ET finally showed up, she would have technology beyond our wildest dreams — beyond our imagining. Well, the flower-ships are pretty, but they aren’t the way we’d choose to travel to the stars—”

“Especially not in this region,” Nemoto said evenly.

“What do you mean?” Maura said.

Nemoto smiled thinly, the bones of her face showing through papery skin. “Now that we are, like it or not, part of an interstellar community, it pays to understand the geography of our new terrain. The interstellar medium, the gases that would power a ramjet, is not uniform. The Sun happens not to be in a very, umm, cloudy corner of the Orion Spiral Arm. We are moving, in fact, through what is called the ICM — the intercloud medium. Not a good resource for a ramjet. But of course the flower-ships are not interstellar craft.” She eyed Maura. “You seem surprised. Isn’t that obvious? These ships, with their small fraction of light speed, would take many decades even to reach Alpha Centauri.”

“But time dilation — clocks slowing down as you speed up—” Maura said.

Nemoto shook her head. “Ten percent of lightspeed is much too slow for such effects to become significant. The flower-ships are interplanetary cruisers, designed for travel at speeds well below that of light, within the relatively dense medium close to a star. The Gaijin are interplanetary voyagers; only accidentally did they become interstellar pioneers.”