MARS, 1976

A THIN WIND, INHUMANLY COLD AND DRY, SWEPT across the Chryse Planitia. Powdery grains of sand moved near the surface, tumbling over one another as they had for uncounted millennia. The scant Martian atmosphere transmitted the soft hiss of colliding silica crystals, though there was no one there to hear it. The sun, small and distant, teased at frozen fragments of water and carbon dioxide, but not enough to coax them from their solid state.

Time passed.

Three meters above the surface, an anomaly appeared. A spark of orange became a miniature orb, then flattened to become a shimmering disc the size of a manhole cover. The disc continued to grow until it was 1.3333 meters in diameter, and the thickness of a hydrogen atom. For the next three rotations of the red planet, the disko hovered patiently above the rock-strewn sands.

A new star mounted the horizon, rose high over the plain, then separated into two lesser objects. One continued in its orbit; the other entered the atmosphere. A parachute blossomed, slowing its descent.

Three intensely bright points of light erupted from the bottom of the object. The parachute broke free and drifted off as the craft continued its descent toward the surface. The three points of light resolved into spikes of blue flame supporting a complicated-looking metallic construction. Slowly, the spacecraft sank through the thin atmosphere. As it neared the surface, three gangly legs unfolded from its belly, giving it the appearance of an arachnid amputee.

The disko, almost directly beneath the descending spacecraft, awakened. Its gray surface became mottled, turned sickly green, then flared bright emerald and spat out a Klaatu. The Klaatu was followed by several others. Their numbers grew to become a crowd of several dozen hovering, ghostlike figures, all looking up at the approaching craft, now clearly recognizable as the Viking 1 lander.

At first, it looked as if the lander would collide with the disko and the waiting crowd of Klaatu, but it missed them by several meters. The touchdown was abrupt; the legs struck the surface, flexed, sprang back. Dust exploded from beneath the rockets and billowed out, creating a huge torus of particulates that quickly distorted and was swept away by the thin wind. The jets sputtered and winked out, the lander settled, the dilute roar of its arrival gave way to the near silence that had persisted for millennia.

Six hundred seconds later, the quiet was interrupted by a buzzing sound. A dish-shaped antenna unfolded from the top of the lander and rotated several degrees until it was pointed at Earth. The Klaatu watched. More buzzing and clicking came from another part of the lander as the camera began to record and transmit images of the rocky plain. From time to time, the sounds would cease, then start up again.

The Klaatu became bored. One by one, they floated back to the disko and were drawn inside, until none were left. The disko remained. The lander continued to perform its various functions. The wind blew. The planet rotated as it continued its long, ponderous journey around the sun.

For several Martian years, the Viking lander continued to transmit information back to Earth, although the clicking and buzzing occurred less frequently. On the 2,248th Martian day after its arrival on Mars, the lander emitted its last click, then fell silent.

Time passed. The disko remained dormant. Dust built up around the legs of the lander and filled its crevasses and openings, making it look less like an alien presence and more like a native thing that had emerged from the sand and stone of Mars.

On the 2,522nd day after the landing of the Viking, the disko awakened, flashed green, and spat out a man wearing a camouflage hunting jacket.

The man landed on his back. The impact drove his last breath from his lungs — a cloud of moist, oxygen-rich air crystalized, then fell like snow to the arid surface. Master Gheen staggered to his feet, gasping for air that was not there, looking around wildly as the surface of his eyeballs froze. He clawed at his chest and staggered toward the lander, but he made it only a few steps before falling to his knees, then pitching forward to bury his contorted face in the red earth of Mars.

Cell by cell, the process of freeze-drying began. Plasma membranes burst, spilling cytoplasm, mitochondria, nuclei. Proteins, prions, and other complex, carbon-based substances flaked from the frozen corpse to violate the delicate Martian ecosystem.

The thin wind blew.

Flecks of silica collided with the alien particles.

The sun rose and fell.

The planet began to die.