To descend to Mars, in a ship assembled by the hands and muscles of humans: to Gershon, still elated to be in space at all, there was something wonderful about the thought.

As long as the mother worked, of course.

“Coming up on two minutes,” Curval called up. “Mark, T minus two minutes.”

“Roger,” Bleeker said. He turned off the tape.

Glancing at his panel, Gershon could see that the ascent stage was powered up, no longer drawing any juice from the lower stage’s batteries. It was preparing to become an independent spacecraft for the first time.

In this test, simulating a launch from the Martian surface, the whole unlikely MEM assemblage was supposed to come apart, releasing the sticklike ascent stage with its ungainly, strap-on propellant tanks.

Gershon knew this was the moment on the mission that was most feared by the engineers at Columbia and Marshall. There were too many ways for the fucking thing to go wrong. Like, the ascent-stage ignition would take place with the engine bell still buried within the guts of the MEM’s descent stage. What if there was a blowback, an overpressure of some kind, before the ascent stage got clear?…

Well, they were soon going to find out.

Bleeker said, “Guidance steering in the PGNS. Deadband minimum, ATT control, mode control auto.”

“Auto,” Gershon responded.

“One minute,” the capcom said.

“Got the steering in the abort guidance.”

Gershon armed the ignition. “Okay, master arm on.”

“Rog.”

“You’re go, Iowa,” said Curval.

“Rager. Clear the runway.”

Bleeker turned to him. “You ready?”

“Sure.”

“That mother may give us a kick.” Bleeker reminded him of the drill. “Okay, Ralph. At five seconds I’m going to hit ABORT STAGE and ENGINE ARM. And you’ll hit PROCEED.”

“Rager.”

“Here we go. Nine. Eight. Seven. Six. Five.”

Beyond the small window in front of Gershon’s face, the shining blue horizon of Earth drifted by, a complex, clearly three-dimensional sculpture of cloud over sea.

The computer display in front of Gershon flashed a “99,” a request to proceed. He glanced across at Bleeker.

Bleeker closed the master firing arm. “Engine arm ascent.”

Gershon pressed the PROCEED button.

There was a loud bang, a rattle around the floor of the cabin. Pyrotechnic guillotines were blowing away the nuts, bolts, wires, and water hoses connecting the upper and lower stages of the MEM.

A weight descended smoothly on Gershon’s shoulders.

“First-stage engine on ascent,” Bleeker said. “Here we go.” He smiled. “Beautiful.”