Vosnesensky was already sliding into the driver’s chair and checking to see that their communications antenna was locked onto the spacecraft up in synchronous orbit.

"What do the satellite photographs show?" he asked.

The sloping transparent roof of the cockpit was so low that Jamie had to bend over as he stood behind the driver’s chair. He could feel the cold of the Martian night seeping through the plastiglass even though Vosnesensky had drawn the thermal shroud for the night.

He answered, "Not enough detail, Mikhail. We’ve got to be there firsthand and see the rock formations close up. Take samples for analysis."

"It would take us at least two days out of our way. A full day or more to get there and the same to return to where we should be. We don’t have enough food on board, and it would be an unnecessary strain on the air recycling system. And it would wreck the mission schedule."

"Come on, Mikhail! We can stretch the food. The fuel cells produce clean water and the air recyclers are good for months. You know that. And there’s a full week between this excursion and the next one."

"Twenty hours of driving, even without stops."

"I’ll help you with the driving," Jamie said, grinning. "I’ve driven pickup trucks over worse terrain than this."

The Russian turned in his seat and fixed Jamie with those clear blue eyes. "This is not New Mexico."

"That’s right," Jamie replied. "This is Mars. And we’re here to explore this new world. There’s important scientific work to be done here, Mikhail…"

"You scientists always want to break the rules."

"Damned right!" Jamie snapped. "We’re here for the sake of science. To explore. To learn. To seek out the truth wherever it leads us."

"Pretty words," grumbled Vosnesensky.

"Men have died for those ideas!"

"Yes. That is exactly my point."

"We’ve come a hundred million kilometers—" Jamie was almost shouting — "What the hell is another day or two of travel?"

"It is not authorized. It is not on the excursion plan. The mission controllers back on Earth would disapprove."

"Fuck ’em! We’re here, Mikhail. The reason we’re here is to learn. We can’t do that by sticking to plans written a year ago. They might as well have sent unmanned machines if they’re going to make us behave like goddammed robots."

Vosnesensky took a deep breath, then exhaled slowly, like a man trying to control his temper. "We are not robots, but we are responsible to higher authority. The purpose of this mission is to start the exploration of Mars. If we displease those in charge, there will be no more missions and the exploration will end."

Jamie squatted down on his heels, one arm on the back of Vosnesensky’s chair to steady himself. Forcing himself to sound more reasonable he said, "Mikhail, as far as I’m concerned all the politicians on Earth can take a flying leap into the Grand Canyon. What makes you think they’re going to authorize more missions to Mars, no matter how obedient we are? We’re here, now. Now’s the time to find out as much about this world as we can. The more knowledge we acquire now, the harder it’ll be for them to deny us follow-up missions after we return."

"You are skating on thin ice, Jamie."

"Maybe. I thought you Russians were all great gamblers," Jamie coaxed.

Vosnesensky stiffened visibly. "I am not here to gamble. Not with lives. Especially my own."

"But it’s not that big a risk," Jamie urged, quickly switching tactics. "We can do it! We don’t have to stick to the plans they wrote for us on Earth. The mission orders allow us some flexibility. We’ve got an opportunity here to make a fundamental discovery about the geological history of this planet."

"It is an unnecessary risk."

Jamie made himself grin at the Russian. "Look at it this way, Mikhail — if we kill ourselves you won’t have to face Dr. Li or the mission controllers back at Kaliningrad."

Vosnesensky stared at him for a long moment, then burst into a peal of laughter. "You are a fatalist!" the cosmonaut said. "Just like a Russian."

"You’ll do it?"

"It is not in the excursion plan."

"So we change the plan," Jamie said. "The rover’s got the range and we’ve got enough supplies on board. If we get stuck, Mironov can come out with the other rover."

Vosnesensky’s beefy face returned to its normal scowl. He said, "We cannot deviate from the excursion plan. It is not allowed."

Jamie felt himself tensing. With deliberate care, he slowly rose from his squatting position. "In that case," he said evenly, "mission regulations give me the right to go over your head and appeal directly to Dr. Li. I want to talk to Li."

Still frowning, Vosnesensky reached out across the control panel and flicked on the communications set.

"Speak to the expedition commander then," he growled. "Let him take the responsibility."

"To Tithonium Chasma?" Dr. Li was startled. "But that is a thousand kilometers away from your present position."

"Its western edge is less than six hundred kilometers from our present position," replied James Waterman.

Li sank back in his upholstered chair. He had retreated to his private quarters to take the expected check-in call from Vosnesensky, partly for his own comfort and partly because he felt he could deal with whatever problems arose more easily without the technicians and other team members crowding around him at the communications console of the spacecraft’s command center.

His compartment was as luxurious as mission regulations allowed. Like all the other privacy cubicles aboard the two Mars spacecraft it was barely large enough to accommodate a narrow bunk, a tiny desk, and a single chair. Li’s chair could tilt back, however, like an astronaut’s acceleration couch. He often used it to sleep in, rather than the bunk, which he found uncomfortably short.

While other team members had decorated their cubicles with photos of their families or maps of Mars or even computer printouts, Li had taped an exquisite set of small silk paintings onto his walls. Mountains shrouded in mist. Beautiful birds perched on a graceful tree limb. A pagoda by a lake. Touches of home. Even if he died in space, he reasoned, he wanted the comfort of those paintings beside him.

But he did not so much as glance at them while he stared into the display screen that dominated his small desk. Waterman’s broad, onyx-eyed face looked back at him. A face that could be very stubborn, Li realized.

"I wish to give you as much latitude as possible," Li said, "but adding three extra days to your traverse seems excessive to me."

He did not add that Vosnesensky was not even supposed to be on this traverse. The Russian should have remained at the base camp, as the mission plan called for. He was already exceeding his directives.

"It’s necessary," Waterman replied. "For geological reasons."

Li almost let himself smile. Of course, for geological reasons. Naturally Waterman would have a sound scientific reason for pushing the limits. A born troublemaker.

Steepling his fingers in his lap, out of range of the comm unit’s camera, Li waited for the geologist’s explanation. Waterman looked eager, black eyes wide and sparkling, lips slightly parted, energy fairly shining from his dark-skinned face.

"We’ve calculated the rover’s fuel reserves and they are more than sufficient to take us to the Tithonium region and back to the base, sir. Plus a generous allowance for reserve."

Li did smile, thinly. Waterman is thinking only of the technical side. To him, the political ramifications simply are not of importance. I wonder if he thinks of them at all.

"Dr. Li, you understand the principles of geology…" And without hesitation Waterman launched into a lecture about the rock formations on Mars.

Li listened with one ear while another part of his mind felt amused at the scientist’s earnestness and the unthinking arrogance of this enthusiastic young man lecturing his elder.