The men climbed back into their machines with mixed feelings.

Four hours of power cutting and heaving of lunar soil and the flat had extended a long way further into the crater wall. But finally, an edge had been found. It had been a surprise too. Phillip had expected to find a sharp slope downward into the moon, like a right angle, but the angle had been oblique. In his mind he had been imagining the flat to be like one side of a giant shard, like an ice berg. But the edge formed a straight line ridge, which intersected another fine ridge in the shape of a 'Y' This edge was followed down on both directions into the lunar soil, until it intersected again, at another perfect 'Y'. Phillip took careful measurements and tapped them into his computer, sending the data back to base for the main computer to analyze.

By the end of the shift, the top and two flat sides of the object had been uncovered. Each flat area was pentagonal Every corner had a 'Y' shape, which led away into the grey lunar soil, and every intersection produced another invariably flat surface, and logic demanded that all the area not visible was much the same as that which stood out starkly in the monotones of light and shadow.

At the end of the day's work shift, the four vehicles lumbered slowly back to base, looking like tired dinosaurs, with their tracks churning up clouds of grey dust, and their arc lights punching through the inky blackness of the shadows.

"So what is it?" said John bluntly, throwing the question out as a challenge.

"Your guess is as good as mine," said Phillip.

"The surface is not Man-made, that's obvious," said Paul.

The other men, who were sitting around the table, acknowledged this observation by the expressions in their eyes.

The computer buzzed out a sheet and a picture flipped onto the screen. Phillip read out:

"Insufficient data. Theoretical projection. Polygon based on spherical model. Metallic. Density unknown. Diameter..." he stopped after the dimensions. It was too much to take in.

"Its just about the whole blooming moon!" gasped John.

FIVE