“Volcanic ash,” she said. “Pumice.” She was straining in her harness, trying to see the battered landscape out of their pilots’ windows. “Low-density stuff; not many rocks. It reflects radar badly. There’s nothing for the landing radar to lock on to.”

“Or maybe,” Stone said, “the landing radar is screwed.”

“Don’t abort.”

Stone and Gershon exchanged looks.

“Nine thousand,” Stone said. “Still no lock.”

They’d already busted the mission rules, Gershon realized.

Stone said, “Ralph—”

And then the warning lights went out. The radar lock had come in.

York gasped, an explosion of relief.

“Jesus.” Gershon slammed his fist into his control station. “We is fucking go.”

“We is indeed,” Stone said tightly.

Gershon twisted over his shoulder to look at York. “I guess we flew right on over all that pumice stone, huh.”

She stared back at him. “I guess.”

He had no idea if she’d just been bullshitting, he realized, about the pumice stone. He didn’t think York was the type to do that, but it was possible. And he also didn’t know if Stone would really have pulled the plug, or let him go on and try to land without the radar.

He didn’t, he realized, know his crewmates as well as he thought he did.

“Eight thousand,” Stone rattled off. “Down velocity one hundred feet per second. We’re go for the landing.”

“Rager.”

Gershon took hold of his controls. He had an attitude control adjuster in his right hand — a joystick with a bright red pistol grip — and on his left there was a toggle switch called the thrust translator controller, which would squirt the down-pointing reaction thrusters to reduce the rate of fall. It was all linked up by the electronics to the reaction control subsystem, which would do most of the steering for him.

He pulsed the reaction control thrusters; solenoids rattled comfortingly.

He handed control back to the computer. “Manual auto attitude control is good.” He felt a surge of renewed confidence. The radar was locked in, and the thrusters were copacetic. When the time came, when he had to take control of the ship for the final landing, he knew that everything would be fine.

“Seven thou,” Stone said. “Here we go. High gate. Right through that gate.”

Under computer control, Challenger tipped up a little more, tilting Gershon forward. He stared ahead. Speeding over the close horizon, they were coming to what looked like an escarpment, a ridge marking out the edge of the cratered terrain. Beyond that ridge, the land looked different: smoothed over, lacking craters, kind of like mud, like a flood plain…

And there was a valley under his prow, snaking north from out of the southern plateau. It looked like a gouge in a woodcut, with a big wide crater just to the northeast.

It looked just like the maps and the models in the back rooms at JSC.

Gershon crowed. “I’ve got it! I have Mangala! Just as fat as a goose.”