The young fool simply does not understand that he is on terribly shaky ground politically. He honestly believes that science is all that matters. Li wished he could live such an uncomplicated life, have such unhampered enthusiasms, pursue knowledge without worrying about those who controlled the purse strings — and the honors.

On the other hand, he reasoned as Jamie continued his nonstop recitation, suppose he kills himself down there? He will become a hero, automatically. And cease to be a problem. He would most likely be killing Vosnesensky also, but that could not be helped.

Li shook himself when he realized where such thoughts were leading him. My task, he said sternly to himself, is to direct the exploration of Mars and allow the scientists to conduct that exploration with as little interference as possible. Waterman wants to go farther and faster than we have planned. The politicians will be angry if anything goes wrong.

It took him a moment to realize that Waterman had finished speaking and was gazing expectantly at him from the display screen. Like a child asking his father for permission to take a new step toward adulthood, Li thought.

He blinked his eyes twice, then heard himself reply, as if from some great distance, "Go ahead with your plan. I will expect you, Commander Vosnesensky, to call an immediate halt the instant you reach the critical point in your fuel supplies."

The camera down below swiveled back to Vosnesensky. "I have calculated the fuel reserves we need to get safely back to base and added a twenty percent emergency factor."

"When you reach that point you must return, no matter where you are or what you are doing. Is that clearly understood?"

"Yes, sir."

"Dr. Waterman?"

He heard Waterman’s voice reply, "Clearly."

"Very well then, proceed." Li reached for the keyboard to end the transmission. He hesitated, though, long enough to add, "And good luck."

"Thank you!" The two men’s voices rang back in unison.

KALININGRAD: In the early days of the Soviet space program, when secrecy born of Cold War fears dominated everything, the locations of space facilities were kept as concealed as possible. The major Soviet launching base, for example, was said to be at Baikonur, a city in the middle of the Kazakh SSR, a land where Mongol hordes and the fierce horsemen of Tamerlane once rode.

Actually the launch center is near the town of Tyuratam, more than three hundred kilometers southwest of Baikonur, on the main rail line from Moscow to Tashkent.

In those days of suspicion there was no public mention of Kaliningrad, the mission control center from which the earliest manned space flights were directed. Gagarin’s pioneering orbit of the Earth, the thousands of man-hours of flight aboard a dozen space stations, and finally the first expedition to Mars — all were directed from the center at Kaliningrad, about six kilometers northeast of the outermost circular motorway ringing metropolitan Moscow.

The protocol for directing the Mars mission had been decided upon long before the various spacecraft had even begun to be assembled in Earth orbit. Knowing that there would be a communications lag of ten minutes or more between Mars and Earth, the mission planners placed full authority in the hands of the expedition commander, Dr. Li Chengdu.

There was no need for Dr. Li to check with mission command at Kaliningrad before making a decision.

The day-to-day operations of the teams in orbit around Mars and on the planet’s surface were his responsibility.

That did not mean, however, that he could not be overruled.

Having given his assent to Vosnesensky and Waterman’s unscheduled dash to Tithonium Chasma, Dr. Li routinely reported the change in the excursion plan back to Kaliningrad. Routinely, in this case, meant that he waited until the end of his day, as usual, before filing his report. The rover team’s diversion to Tithonium was given as item number seventeen of his customary daily report. Seventeen of twenty-two.

So it was slightly after four in the morning in Russia when his report arrived. The mission controllers worked three shifts, of course, but their directors — the men and women who made the real decisions — were soundly sleeping when Li’s report began scrolling on the display screen of the chief controller for this shift.

He was a Russian who took his duties seriously. Sitting beside him at the console was his American counterpart, a perky redheaded engineer on loan from CalTech’s Jet Propulsion Laboratory. Shoulder to shoulder, they read the report from the expedition commander on the display screen, the American woman slightly impatient with her colleague’s slower pace at reading English. The mission control center was quiet and still at this hour. Even though all the stations were manned, there was little activity and less talk.

Until the American controller suddenly exclaimed, "He okayed it! Without checking with us?"

Eyes snapped wide and heads turned toward her.

The Russian chief controller said, "Dr. Li is within his authority…"

"The hell he is," said the American. Her green eyes were blazing fury. "The protocol specifically states that any major change in the schedule must be cleared with mission control first!"

"Major change," the Russian said mildly.

"You don’t think a six-hundred-kilometer diversion of that rover team is a major change?" She yanked the telephone from its receptacle on the console and began pecking out a number. "How much fuel does that buggy hold, anyway? Aren’t they putting themselves in danger of getting stranded?"

The Russian tapped the console keyboard, and the specifications for the Mars rover displaced Dr. Li’s report on their display screen.

"It has a cruising radius of one thousand kilometers," he said. "More than half its mass is fuel. An enormous safety factor."

"Not if they’re throwing in an unscheduled twelve hundred kilometers, it isn’t."

"You are calling the chief mission director at this hour?"

"Hell no, I’m not that crazy," the American answered, a slight grin breaking through her anger. "I’m calling Houston."

The Russian smiled back at her. "Ah — and they will wake up the chief."

"Right. I may be quick-tempered but I’m not stupid."

HOUSTON: The chain of command on Earth was split, like everything else about the Mars mission, into two strands. While mission control was in Kaliningrad, there was a "shadow" mission control team at the old NASA center at Clear Lake, near Houston.

The center had been created in the early nineteen-sixties as a political plum for Texas. Originally designated the Manned Space Center and built nearly an hour’s drive from downtown Houston, the center became the home of the astronauts, the place where all manned space activities were planned and directed. Eventually it was named after Lyndon B. Johnson. As Vice-President, Johnson had chaired John F. Kennedy’s space council and pushed vigorously for the daring program to land Americans on the moon within the decade of the sixties.

But no matter how swiftly the engineers moved, the tides of history swirled faster. By the time the first astronauts set foot on the moon, Kennedy was dead and his successor, Johnson, out of office. The American space program, seemingly at the peak of success, was being gutted and virtually murdered, a victim of the Vietnam War that Johnson had escalated.

Yet the Johnson Space Center remained and even grew. As the hub of all manned space activities, it became headquarters for the hundreds of astronauts recruited to fly the space shuttle and its successors. Men and women trained there before they were allowed to ride up to the American space station Freedom or any of the foreign (or even private) space stations that orbited the Earth.