“Thirty seconds,” Stone said.

York turned briefly to her own workstation. On the first pass around the planet, the science platform was working at full capacity, taking observations of the surface and atmosphere. Even the tail-off of the radio carrier during loss of signal, as Earth was eclipsed by the atmosphere of Mars, would give a lot of information about the structure of the Martian air.

These first observations were important. If the burn went wrong, and the mission turned into nothing more than a flyby, it could be that these contingency observations would be the most significant data that Ares would return.

Ares dipped lower, and swept over the line between night and day. She was granted a brief glimpse of a line of craters picked out by the last of the sun, their wind-eroded rims casting long shadows across the ancient, resilient surface.

“Ares, Houston, coming up to loss of signal,” Young said from distant Mission Control. “You’re go all the way, guys.”

“Thanks a lot,” Stone said. “See you on the other side, John. Ten. Nine.”

…Then the cratered contrast was gone, and Ares flew into shadow, over a land immersed in unbroken darkness. The Solar System is full of empty, unlit worlds, she thought. Earth is the exception. She felt isolated, vulnerable. A long way from home.

“Three. Two. One.”

Static burst from the grilles on the science-station racks, from the little speakers in her headset.

LOS had come right on time. That meant their trajectory was true.

Gershon laughed, explosively. “How about that. Right on the button. Hey, Phil. I wonder if they just turned it off. Wouldn’t that be terrific? I can imagine John saying, ‘They’re just a bunch of uptight assholes. Whatever happens, just turn the damn thing off…’ ”

York could see Stone in profile, beyond the cupped headrest of his couch. He was grinning, but it was a tight grin that showed a lot of teeth. “Let’s go to the MOI checklist, Ralph. Ah, coming up on ten minutes fifteen to MOI.”

York craned her head upward, staring at the circular patch of darkness that was Mars. She summoned up a map of the surface in her mind. Ares was traveling over the Hesperia Planum, another volcanic plain to the east of Syrtis, close to the equator.

She could see traces, outlines, glimmers of white against the darkness. Has to be starlight, picking out the CO2 ice.

She had seen nomads’ campfires burn, pinpricks in the night of the huge deserts of Earth. But there were no fires in the Martian desert. In fact, of all the worlds of the Solar System, only Earth — with its oxygen-rich atmosphere — knew fire.

“Five minutes to the burn.”

She was sealed into her suit, shut in with the hiss of oxygen, the whir of fans, the scratch of her own breathing. She felt isolated, cut off. Lousy design. I need to hold somebody’s hand.