Two months to the day after leaving Cape Canaveral, the Zeus IV landed on Mars, whose sombre presence had loomed ever more threateningly for the previous weeks. Signals blackouts caused by the planet’s magnetic field added their own thrills and panics, skilfully orchestrated by NASA’s PR specialists. But the landing was a triumph, celebrated by the hoisting of the Stars and Stripes and, behind it, the flag of the United Nations.

Within an hour the crew of the Zeus IV was standing on Martian soil beside the spacecraft, intoning their carefully rehearsed ‘Hymn to the Space Age’. From that moment no Congressman dared to deny the NASA chiefs anything they demanded.

For the next six weeks public interest in the Mars mission remained high, sustained by NASA’s careful attention to the emotional needs of the worldwide audience. Life within the spacecraft was presented as a cross between a TV sitcom and a classroom course in elementary astronautics. The crew tolerantly went along with these charades. Dr Valentina was seen replacing a filling in Commander Merritt’s mouth, and Professor Kawahito, the heart-throb of a billion Asian viewers, won a hard-fought chess tournament against the Zeus IV’s combined on-board computers. Romance was in the air as Dr Valentina’s cabin door remained tantalizingly ajar. The TV cameras followed the crew as they drove in their excursion vehicles across the fossil Martian seas, collecting rock samples and analysing the local atmosphere.

At the halfway stage of their mission the crew revealed a mild impatience with the media roles imposed on them, which the NASA psychologists attributed to a greater maturity brought on by a sense of planetary awe. To remind them of Earth, the astronauts were urged to watch episodes of Dallas, Dynasty and The Flintstones, and to take part in a series of Oval Office interviews with President Quayle. But their spirits lifted as the day of departure drew near. When the Zeus IV rose at last from the Martian surface the entire crew burst spontaneously into an unscripted cheer, in which some observers detected a small note of irony.

Ignoring this impromptu levity, NASA planned a lavish reception at Edwards Air Force Base, where the Zeus IV would land. Every Congressman and Governor in the United States would be present, along with President Quayle, the heads of state of thirty countries and a host of entertainment celebrities. An unending programme of media appearances awaited the astronauts — there would be triumphal parades through a dozen major cities, followed by a worldwide tour lasting a full six months. NASA had already appointed firms of literary agents and public relations experts to look after the commercial interests of the astronauts. There were sports sponsorships, book contracts and highly paid consultancies. The news of these deals was transmitted to the home-coming crew, who seemed gratified by the interest in their achievement, unaware that whenever they appeared on screen their images were accompanied by the cash totals now committed to them. Two days before the Zeus IV landed, NASA announced that three major Hollywood studios would collaborate on the most expensive film of all time, in which the astronauts would play themselves in a faithful recreation of the Martian voyage.

So, at 3.35 pm on April 29, 2008, the Zeus IV appeared in the California sky. Accompanied by six chase planes, the spacecraft swept down to a perfect landing, guided by its on-board computers to within 50 metres of President Quayle’s reception podium. The stunned silence was broken by an immense cheer when two of the astronauts were glimpsed in the observation windows. The crowd surged forward, waiting for the hatches to open as soon as the landing checks were over.

Despite the warmth of this welcome, the astronauts were surprisingly reluctant to emerge from their craft. The decontamination teams were poised by the airlocks, ready to board the spaceship and evacuate its atmosphere for laboratory analysis. But the crew had overridden the computerized sequences and made no reply over the radio link to the urgent queries of the ground controllers. They had switched off the television cameras inside the craft, but could be seen through the observation windows, apparently tidying their cabins and changing into overalls. Dr Valentina was spotted in the galley, apparently sterilizing her surgical instruments. A rumour swept the review stands, where President Quayle, the Congress and invited heads of state sweltered in the sun, that one of the crew had been injured on re-entry, but it soon transpired that Dr Valentina was merely making soup. Even more strangely, Professor Kawahito was seen setting out six parallel chessboards, as if preparing for another tournament.

At this point, an hour after their arrival, the crew became irritated by the grimacing faces pressed against the observation windows, and the interior shutters abruptly closed. This dismissive gesture made the crowd even more restive, and the ground staff tried to force the main hatch. When they failed, the head of NASA’s crash recovery team began to pound on the locks with a baseball bat borrowed from a youngster seated on his father’s shoulders. The first whistles and jeers rose from the crowd, who jostled the scaffolding towers on which the impatient TV crews were waiting. A cameraman lost his footing and fell through the roof of a parked bus. Loud-speakers blared meaninglessly across the million or more spectators sitting on their cars around the perimeter of the airfield. The heads of state, diplomats and generals consulted their watches, while President Quayle, making involuntary putting movements with the portable microphone in his hands, beckoned in an unsettling way to his military aide carrying the briefcase of nuclear launch codes. The boos of the crowd were only drowned when a squadron of jet planes flew low over the field, releasing streams of red, white and blue smoke. Ordered away by the frantic control tower, the victory flight broke up in confusion as the pilots returned to their muster points in the sky, leaving a delirium of crazed smoke over the Zeus IV.

At last calm was restored when a company of military police took up positions around the spacecraft, forcing the crowds behind the VIP stands. Led by President Quayle, the dignitaries shuffled from their seats and hurried along the lines of red carpet to the refreshment tents. The TV cameras trained their lenses on the Zeus IV, watching for the smallest sign of movement.

As evening fell, the spectators beyond the airfield perimeter began to disperse. Powerful arc-lights bathed the spacecraft, and during the night a fresh attempt was made to contact the crew. But the messages in morse code tapped on the hull, like the laser beams shone at the darkened observation windows, failed to draw any response. No sound could be heard from the interior of the craft, as if the crew had settled in for the night, and a hundred theories began to circulate among the NASA chiefs and the teams of doctors and psychiatrists summoned to their aid.

Were the astronauts in the last stages of a fatal contagious disease? Had their brains been invaded by an alien parasite? Were they too emotionally exhausted by their voyage to face the reception awaiting them, or gripped by so strong a sense of humility that they longed only for silence and anonymity? Had an unexpected consequence of time dilation returned them psychologically hours or days after their physical arrival? Had they, perhaps, died in a spiritual sense, or were they, for inexplicable reasons of their own, staging a mutiny?

Surrounded by the deserted stands and the silent bunting, the NASA chiefs made their decision. An hour before dawn two thermal lances played their fiery hoses against the heat-resistant plates of the spacecraft. But the carbon-ceramic hull of the Zeus IV had been forged in temperatures far beyond those of a thermal lance.