For all its size, this director mirror had very little mass. Originally it had been planned to be made of glass in much the same manner as Palomar's 200-inch eye. But this plan had been rejected on the basis of the weight involved. Instead, its structure was a rigid honeycomb of plastic; surfaced by a layer of fluorocarbon plastic which had been brought to its final polish in space, and then carefully aluminized to provide a highly reflective, extremely flat surface. This mirror was also cooled by the liquid nitrogen supplied from the back side of the big mirror. Necessarily so, since even its best reflectivity still absorbed a sufficient portion of the energy from the beam it deflected to have rapidly ruined it if it were not properly cooled. The several tons of ruby rods in the barrel, with their clear sapphire coatings, were far more valuable than any gems of any monarch that had ever lived on Earth. Synthetic though they were, Steve Elbertson, the project's military commander, knew they had been shipped here at fantastic cost and were expected to pay for themselves many thousands of times over in energy delivered. * * * * * As yet, the project had had no specific target; nor had it been fully operational as of midnight yesterday. But this "morning" for the first time the terrific energy of the laser beam would be brought to bear on the Greenland ice cap--three hundred seventy-five million watts of infrared energy adjusted to a needle-point expected to be twenty-two feet in diameter at Earth's surface, delivering one million watts per square foot, that should put a hole a good way through the several thousand feet of glacier there in its fifteen minutes of operation, possibly even exposing the bare rock beneath, and certainly releasing a mighty cloud of steam. Focused to this needle sharpness, the rate of energy delivery was many orders of magnitude higher than that delivered by man's largest nuclear weapons only a few yards from ground zero. Today's test was primarily scheduled as a test of control in aiming and energy concentration. Careful co-ordination of the project by ground control was vital, so that no misalignment of the beam could possibly bring it to bear on any civilized portion of Earth's surface. For, fantastic as this Project Hot Rod might be as a source of power for Earth, Major Elbertson knew that it was also the most dangerous weapon that man had ever devised. Therefore, the scientists were never alone in the control booth, despite the mile-long security records of each. Therefore, he and his men were in absolute control of the men who controlled the laser.