In the depths of the mission — suspended between planets, with nothing visible but sun and stars beyond the walls of the craft, and ground down by the stultifying routine of long-duration flight — York had suffered some deep depressions. She’d shrunk into herself, going through her assignments on autopilot, shunning the company of her crewmates. She suspected they’d suffered similarly, but they seemed to have found ways to cope: Gershon with his love of the machinery around them, Stone with his little pet pea plants.

Already she was dreading the return journey; it loomed in her imagination, a huge black barrier.

But that was for the future. Just then she was climbing out of the pit, up toward the warm ocher light of Mars.

She spent as much time as she could just staring at the approaching globe, identifying sites no naked human eye had seen before, as if claiming more and more of Mars for herself.

As they prepared for the ignition, Bleeker had “Born in the USA” playing on the cabin’s little tape deck. It drowned out the clicks and whirs of the MEM’s equipment.

Bleeker said, “Ascent propulsion system propellant tanks pressurized.”

“Rager,” Gershon replied.

“Ascent feeds are open, shutoffs are closed.”

On the ground, Ted Curval was capcom today. “Iowa, this is Houston. Less than ten minutes here. Everything looks good. Just a reminder. We want the rendezvous radar mode switch in LGC just as it is on surface fifty-nine… We assume the steerable is in track mode auto.”

Gershon said, “Stop, push-button reset, abort to abort stage reset.”

Bleeker pushed his buttons. “Reset.”

Curval said, “Our guidance recommendation is PGNS, and you’re cleared for ignition.”

“Rog. We’re number one on the runway…”

A hundred miles above the Earth, as Gershon and Bleeker worked through the litany of the preburn checklist, MEM and Apollo drifted in formation. The Apollo, containing Command Module Pilot Bob Crippen, was an exquisitely jeweled silver toy, drifting against the luminous carpet of Earth. And the MEM was a great shining cone, at thirty feet tall dwarfing Apollo, surrounded by discarded Mars heat-shield panels and rippling with foil.

Its six squat landing legs were folded out and extended. But MEM 009 was destined to land nowhere.

Gershon stood harnessed in place beside Bleeker in the cramped little cabin of the MEM’s ascent stage. He felt bulky, awkward in his orange pressure suit. In front of Gershon was a square instrument panel, packed with dials and switches and instruments. There were two sets of hand controllers, one for each man. More circuit breakers coated the walls, and there were uncovered bundles of wiring and plumbing along the floor.

The cabin had two small triangular windows, one to either side of the main panel, calibrated with the spidery markings that would help guide a landing on Mars. Blue Earthlight shone through the windows, dappling the cabin’s panels.

Behind Gershon there were three acceleration couches, two of them folded up. On a landing flight there would be a third crewman in here, the mission specialist, a passenger during the MEM’s single brief flight.

The cabin’s surfaces were utilitarian, functional, mostly unpainted. The metal panels were just bolted together, the bundles of wires lashed in place by hand. You could see that the MEM was an experimental ship: the product of handcrafting, of thousands of man-hours of patient labor, and based on conservative designs, stuff that had worked before.

The apparent coarseness of the construction, with everything riveted together as if in a home workshop, was the feature of space hardware that most surprised people used to sleek mass-produced technology. It was nothing like Star Trek.

But to Gershon the MEM was real, almost earthy.

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.”

After his unexpected assignment to the prime Mars crew, Gershon had been happy to be bumped onto this D-prime test mission. His first flight into space might not have been the most glamorous in the MEM test program — that would probably be the one remaining E mission, the attempt to bring a reinforced MEM in through the Earth’s atmosphere and land it on the salt flats around Edwards Air Force Base. That had been given to an experienced crew led by John Young. But the D-prime, an eleven-day Earth-orbit shakedown flight, was arguably the more important test. In an untried spacecraft, the crew would rehearse every phase of the Mars landing mission save only the atmospheric entry and final powered descent; and, as well, they would rehearse many contingency procedures which might save future missions.

Already, in the MEM, Gershon and Bleeker had ventured as much as a hundred miles from Apollo. In a craft which nobody had tried to rendezvous with before. Which didn’t have a heat shield strong enough to get them back to the ground. And on top of that, the whole flight was in low Earth orbit, where communications and navigation challenges were even tougher than on, say, a flight to the Moon.

If they got through this flight the MEM would be man-rated, with only the Mars heat shield remaining to be test-flown. It was a connoisseur’s spaceflight, a flight for true test pilots.