“Maybe they don’t see us.”

“That’s not possible, George.”

“Then why don’t they respond? This has to be just as significant for them as it is for us.”

“Don’t know,” she said. “Be careful about assumptions.”

“We’re still not hearing anything on the radio, right?”

“No.”

They kept trying. They passed through the last of the night, crossed the terminator, and emerged into the dawn. And they watched Cobalt rise. The chindi glided across the arm of the world.

Meantime they took to magnifying and enhancing the pictures. It was just a rock with propulsion tubes. And sensor arrays. But here was something.

Tor put his finger on a dot. It was between a couple of low ridges. They went to maximum mag, and Alyx said she thought it looked like a radio antenna.

“I think,” Hutch said, “it’s a hatch.”

THEY CONTINUED TO acquire data on the chindi. The Memphis, which measured sixty-two meters stem to stern would have been barely visible alongside it, less than 1 percent of its length.

Bill took pictures, and they spent hours going over them while the Memphis repeated George’s greeting endlessly. They found other hatches, in sizes varying from about two meters across up to twenty or more, all the same color as the surrounding rock.

“Hutch.” Bill’s voice dropped into its lower ranges. His concerned ranges. “There’s been a launch. Something has left the ship and gone into orbit.”

“On-screen.” It was a bottle-shaped object, neck thrust forward. Its hull was smooth.

“It’s a different design from the objects we saw earlier.”

She could make out exhaust tubes. “How big is it?”

“Almost as long as our lander. Maybe a couple of meters shorter. Three meters diameter at its widest.”

“Okay, Bill,” she said. “Let me know if anything changes.”

Later, he was back with more: “Hutch, I believe I can see how they’re creating the Slurpy.”

Physics and meteorology weren’t her strong suits. Or anybody else’s in that group. But she knew that Bill had expectations. “Explain,” she said.

“A ship as massive as the chindi requires enormous amounts of fuel. If it attempted to use scoops of the type that we have, it would have to stay in orbit for years to collect enough hydrogen, or it would have to do an atmospheric entry and cruise around in the troposphere.

“To do that would require substantial design compromise to reduce friction, and it would waste substantial quantities of its newly acquired fuel getting back out of the gravity well.”

“So what’s the solution?”

Bill appeared in the opposite seat, wearing a soft white shirt open at the collar and dark green slacks. One leg was crossed over the other. “The solution is a percolator,” he said.

“A percolator.”

The Slurpy blinked on. They were looking at it from the side, watching the jet welling up from below, the storm bubbling like a volcano, an enormous explosive mushroom, rising above the clouds and spreading in all directions. A blinking line appeared in the jet, extending into the center of the storm. “That’s a tube,” said Bill. “As nearly as I can make out, it goes about three hundred kilometers down from the Slurpy.” Deep in the troposphere, the blinking line, the tube, metamorphosed into a kind of funnel, a tornado shape, except that it was reversed, widening as it reached down through the atmosphere. The tornado rose and sank in the high winds that blew it first one way and then another. But it held together. It was moving in the lower depths, keeping pace with the Slurpy.

“It’s traveling about 1400 kph,” said Bill.

“And this thing is making the storm?”

“I think so. What they seem to be doing is transferring gas from the troposphere out of the gravity well. The idea would be to create a reservoir of hydrogen out in orbit with which the ship can rendezvous.” Bill was clearly pleased with himself. “They do it by percolating the gas at the lower levels. And please don’t look so skeptical. The engineering would really be quite simple.

“One need only lower a flexible drone, constructed of, say, a lightweight plastic, down into the tropopause. At the equator, by the way. It has to be done at the equator.”

“Okay. Then what?”

“We put an efficient fusion reactor in the drone. About one hundred kilometers below the tropopause, temperatures are just under one hundred degrees Kelvin, the pressure is around one atmosphere, and the composition is primarily ammonia ice. The drone inflates into the big funnel that we see, narrow end up.”

“Wouldn’t it be heavy? What keeps it up?”

“Use light material, Hutch. And some balloons, if necessary. The reactor is turned on. It grabs and heats whatever’s near by. The whole assembly is bottom heavy, so it just bobs around the planet on 1400-kph winds. It has the same dynamic as a plastic fishing bob with one of those spring-loaded plungers at the top.”

A schematic appeared on-screen.

“The reactor is positioned inside the funnel, at the throat. As it heats the surrounding slurry, the ammonia ice and gas is propelled up the tube and expelled into space. And you have your snowstorm. Your refueling station.

“When the chindi’s tanks are full, the percolator is deflated, stowed, and, I assume, returned to the ship.”

They had all been listening. “It strikes me,” George said, “that it would be simpler to build a smaller ship. Something with less mass.”

“It would be simpler,” said Tor. “There must be a reason they want a big ship.”

THE CHINDI COMPLETED a second orbit and was making again for the Slurpy. The Memphis was trailing, letting the range open to a thousand kilometers. Bill was still directing George’s message of peace and greeting when George abruptly told her to shut it down. He seemed personally offended.

“Do it, Bill,” Hutch said. She was alone on the bridge.

“Okay, Hutch. And it looks as if we’re getting a second launch over there. Yes, there it goes.” He put it on-screen. “Another bottle. And the first one is lifting out of orbit.”

“Can you tell where it’s headed, Bill?”

“Negative. It’s still accelerating. Moving at seven gees and going up fast.”

“Not in this direction?”

“No. Not anywhere near us.”

“Okay,” she said. “George, we could use some fuel ourselves. We talked about going through the Slurpy before. I think this would be a good time.”

He nodded. “Maybe it’ll get their attention.”

“I doubt it.”

Tor and Nick both looked worried. “You really think,” asked Nick, “we can do that?”

“It shouldn’t be a problem. And it beats spending a few days skimming the upper atmosphere. No, we should be all right. They got through.”

“They’re a lot bigger than we are.”

“We’ll take it slow.”

But even Bill seemed doubtful. When she went up to the bridge and he could speak to her alone, he asked whether she was sure it was a good idea.

“Yes, Bill, it’s a good idea. Put out the scoops and retract everything except the sensors.”

“The chindi has just reentered the storm.”

“Okay.”

Her commlink blipped. It was Alyx, who was with the others in mission control. “The displays just went off,” she said.

“Alyx, that’s because we shut the imagers down for the passage through the Slurpy.”

“Is that necessary?” rumbled George.

“It’s a precaution.”

“Let’s take the chance. We’d like to see this.”

“Okay,” she said. “Visibility will probably be pretty restricted once we get into it.” Bill reactivated two of the imagers, one on either beam. She fed the pictures down to mission control and put them up on her own overhead.

“Thank you,” said Alyx.

“Welcome.” She directed her passengers to activate restraints. “Bill, what’s happening with the two bottles?”

“The first one continues on its original course, Hutch. It’s still accelerating. I cannot see any probable destination. The other has just lit its engine and appears to be about to leave orbit. In fact it is doing so now.”