Camouflage

—33—

Europa, under its ice surface, was not too difficult. They considered not trying it at all, since the environment—cold saline solution under pressure—wasn’t all that different from the Tonga Trench, where it evidently had been since approximately the dawn of time. Of course that also was a good argument for doing it. The artifact might respond to the familiar.

It showed no gratitude for Old Home Week, though, sitting as passively as ever, mirroring the ambient temperature but not otherwise acknowledging their efforts. It was a good test for the containment dome’s integrity, which was going to be challenged by Jupiter, but otherwise did nothing other than raise the blood pressure of the observers along with the water pressure inside.

After Jan had finished her familiar algorithm, they depressurized and drained the dome, and prepared it for Io, the innermost of the four large moons, the Galilean satellites.

Io’s atmosphere is exotic and variable, but thin almost to the point of being a vacuum. It can get up to about a hundred nanobars and down to one (the air on the top of Mount Everest is 330 million nanobars). The fact that it’s a poisonous mixture of sulfur dioxide and sodium isn’t relevant to human survival; a human would freeze solid in the middle of explosive decompression, not having time to notice that the air smelled bad.

Still, it was possible that Io’s surface conditions were not unusual in the universe, so they went ahead with the model, a frigid near-vacuum with a scattering of frozen sulfur dioxide on the floor. They varied the temperature from 100 degrees K. to 130 degrees, enough for some of the sulfur dioxide to sublimate, and then fall back as snow.

The artifact faithfully mirrored the changes in temperature, but otherwise ignored the investigation.

It wasn’t much of a change to simulate Pluto, just suck out the sulfur dioxide, lower the temperature to minus 233, and put in a dusting of snow: solidified nitrogen, methane, and carbon monoxide, with a squirt of ethane flavoring the nitrogen. To any Earth creature, it would be indistinguishable from Io, but conceivably might make all the difference in the world to you, if you were used to living on a snowball in Hell.

They used the space suits for the last time—that was a part of the deal, that they record the suits’ performance in the various environments—and then sent them back to NASA. They would be no help for Jupiter.

For the other planets, they had simulated surface conditions. That wouldn’t be possible on Jupiter. Theoretical models allowed the possibility of a rocky core, but you can’t get there. As you descend through Jupiter’s increasingly thick atmosphere, it becomes more like a star than a planet—the temperature coming to about thirty thousand degrees and the pressure about 100 million atmospheres. It’s “liquid metallic hydrogen” there, and if anything could live under those conditions, it was unlikely to find Earth interesting.

Jan decided to try two Jovian regimes: the one deep enough into the atmosphere that it enjoyed the same air pressure as Earth at sea level, though the temperature was minus 100 degrees C, and the deeper one where the pressure was five atmospheres, but the temperature was an Earth-like zero degrees. In both cases the atmosphere was about 90 percent hydrogen, and the rest helium with a little spicing— methane, ammonia, ethane, acetylene.

In terms of temperature and pressure, it was a lot easier to handle than Venus. But carbon dioxide isn’t flammable. She looked at the huge tanks of hydrogen waiting for the high-pressure phase and tried not to think of it as a fireball waiting to happen.

It was more than a thousand times the quantity of hydrogen that exploded in the Hindenburg disaster.

By now, most of the people, Jan included, had little hope that the artifact was going to respond to anything. When it did, they thought it was an experimental error.

The thing inside the artifact didn’t think, not the way humans think. It didn’t pose problems and solve them. It didn’t wonder about its place in the universe. It felt no real need to communicate.

Its mandate was survival, and it had powerful tools to that end. If the life that decorated the surface of this planet seemed to be a threat, it could simplify the situation. It had patience, fortunately, beyond any human reckoning of the term. All this tapping and zapping and flashing—it could stop the annoyance with one exercise of will, fry the planet clean.

But a central part of it was still out there. It could wait for its return. Maybe, it finally decided, speed up the return by tapping back.

When the changeling got off the plane at the Apia airport, the place was crazy with celebration, even though it was three in the morning. A couple of dozen young men and women danced and clapped and sang in harmony; bunting and flags were everywhere.

When it had boarded in Hawaii, it couldn’t help noticing that several of the Caucasian passengers were unusually old. When the singing stopped, while it was waiting for its luggage, it found out what the story was. It was the sixtieth anniversary of Samoa’s independence, and these old guys were the last survivors of the American forces that had been stationed here in World War II.

Bataan came back in a rush of bad memory, while the mayor of Apia welcomed the old vets and told stories she’d heard from her father and grandfather. The changeling listened respectfully, its face revealing nothing.

It was a pretty face. The changeling had the form of a young attractive woman.

The ad it had answered on the net was looking for a laboratory technician who could operate this and that machine and had knowledge of marine biology and astronomy. It didn’t call for doctorates in those subjects, but then the changeling could hardly advertise those. Its faked credentials were impressive enough; it only claimed “wide reading” in marine biology and a B.S. in astronomy. (The degree actually belonged to the woman whose appearance it had taken. Safely out of the job market herself, she was the mother of triplets in Pasadena.)

Putting together a fake identity was more complicated than it used to be. It was not particularly hard for the changeling to pretend to be the woman from Pasadena; it even had her fingerprints and tattoos and scent. But it had taken a bit of computer wizardry to erase the records of her husband and triplets and substitute an impressive job record. It had taken even more to temporarily make sure that computer, phone, and fax messages were routed through the changeling before Rae Archer got them.

The actual Rae Archer was beautiful, and took pains to look less than her thirty years. The changeling modified the details so that it was the same face, but merely pretty, and thirty.

It had done it all in less than a day, once the ad appeared on Shy and Telescope’s website. (It automatically monitored anything with the key words “Apia” or “Poseidon Projects.”) As Rae, it had talked to Naomi and then Jan, who agreed to give Ms. Archer an interview if she were willing to gamble the airfare out to Samoa and back. The changeling thought it had done a good job of imitating an excited young woman trying to contain her enthusiasm.

The real gamble, of course, was background checking. The changeling had inserted files attesting to Rae Archer’s job competence in every position she’d held. But if Naomi or Jan decided to call the States and ask for an actual person’s recollection of the woman’s work, the web of deception would evaporate.

Apia was muggy and buggy at three in the morning. Almost every cab in town was waiting outside the airport—the plane from Honolulu only came in twice a week—but the changeling asked directions and did the sensible thing, taking the bus into town. It was twenty miles of slow driving either way. For an extra three dollars, the bus went a block out of its way and delivered the changeling to its door, a bed-and-breakfast just a kilometer up the beach from the Poseidon site.

The proprietor was there, heavy-lidded but friendly, to show the changeling to its room. It feigned a couple of hours’ sleep (while relaying four e-mails to the real Rae Archer and monitoring a wrong number) and then went out to watch the dawn come up over the mountains.