Gershon felt a stab of fury. Other data was still good. Velocity looked fine, and the altitude estimates from both AGS and PGNS were in agreement. But without the radar — and even if the altimeter worked — he was screwed. The mission rules said, No radar lock by ten thousand feet and you abort.

Stone said, “Try cycling the landing radar breaker.”

Gershon pulled out the radar’s circuit breaker, his muscles tense with anger, and shoved it back in its slot. “Okay, it’s cycled.”

The caution lights continued to show. No lock.

He turned to look Stone in the eye. “Fine day for a landing.”

He meant: Fuck the rules. Fuck the radar. Fuck Houston; they’re so far away we’ll be on the surface by the time they know what’s going down. We’ve come too far to quit now. I say we go for a landing, by eye if we have to. Fuck it.

Stone stared back at him.

Damn it, you cold bastard. What are you going to do?

Gershon could feel the cabin tip up around him; beyond his big window, sky and a fine edge of red landscape slid past. Challenger was beginning to pitch up, as it dropped closer to the ground.

“Twenty-four thousand feet,” Stone said. “Coming up to throttle down. Mark.”

The primary guidance program would take the descent engine down to 60 percent thrust. Gershon could feel the thin vibration subsiding smoothly. Right on schedule. “That felt good,” he said. “Better than the sims.”

“Twenty-one thousand. We’re still go. Apart from the radar lock. Velocity down to twelve hundred feet per second.”

Twelve hundred. Aircraft speed. Gershon took hold of his controls. I’m flying in the atmosphere of Mars. He looked out of his window. The stars were all washed-out, and the sky was a tall dome of brown light. And he could see the ground. It was a rumpled landscape that slid underneath him. Visibility was good: the contrast, the shadows cast by the low morning sun, made everything stand out.

Challenger was approaching the landing site in a broad sweep from the southwest, so it was flying over the ancient, cratered terrain of the southern hemisphere. It was almost like a lunar landing sim, with craters piled on craters, some so old and huge they were almost obliterated by newer strikes. But these craters had sand dunes rippling across their floors, and there was one big old fellow whose walls looked like they had collapsed under a stream of running water. The Moon, it ain’t.

The landscape was desolate, curving tightly, forbidding. It was an empty planet, no ground support… No runway lights down there, boy. On the other hand, nobody shooting at your ass, either.

“Seven minutes thirty,” Stone said. “Sixteen and a half thou. Coming up on high gate. Still no lock.”