Trail of the Lunik

Russian spacemen crowed last week, and they had plenty to crow about. They had hit the moon, and U.S. scientists were not inclined to minimize their achievement. Furthermore, the Russians declared that they had been able to guide their missile in midflight, correcting its course to make sure it hit its target.

Turn in Space. The Russians issued no explanation of how this was done. Easiest way is to turn the final-stage rocket in a desired direction by gyros or gas jets and then burn additional fuel to speed it up, slow it down or move it sideways. The necessary orders can be given by radio from the ground or by the rocket's own inertial guidance system. If the orders came from the ground, the problem was to get an accurate track of the rocket's course. The cloud of glowing sodium that the rocket released may have been used to reveal its position, allowing the scientists to get a visual fix and to radio the proper corrective maneuvers to the rocket.

U.S. scientists know how to build such a guidance system, but they are frustrated. U.S. first-stage rockets do not have the power to launch toward the moon an object big enough to carry guidance apparatus. So the aim of U.S. moon probers has to be right from the start--like firing a rifle bullet from a moving platform at a distant and moving target. This is much harder than the Russian system, which is more like navigating a ship into harbor.

New Crater. The Russians themselves do not claim to know precisely where the Lunik landed. Astronomers from the Ukraine's Kharkov Observatory, who watched and photographed the moon at the moment of impact from a high-flying airplane, think they saw 'a light effect" at the right instant. U.S. astronomers doubt it. Moon Expert Gerard Kuiper of the University of Chicago thinks that no flash of impact would have been visible against the moon's sunlit surface. He questions a Hungarian report of seeing a long-lasting dust cloud on the moon. Since the moon has virtually no atmosphere, dust particles tossed up from the surface will follow trajectories like bullets, and fall back or disperse in a few seconds.

But Lunik II undoubtedly blasted a crater, which Kuiper estimates as about 100 ft. in diameter with walls 10 ft. high. If such a crater happened to be in a smooth place, it should be detectable by a powerful telescope, under ideal conditions, as a faint bright spot. If the Lunik crater were inside a big crater or in a jumble of craters, it would probably not be visible.

There were skeptics who questioned whether Lunik got to the moon at all. Since the only tangible evidence of a hit was the sudden stopping of its radio signals, the Russians might have set the signals to turn off automatically at a predetermined time while Lunik II soared on past the moon (as Lunik I did).

British radio astronomers do not think this deception was possible. With the giant Jodrell Bank radio telescope, they measured Lunik II's slowly decreasing speed as it climbed through the earth's gravitational field. Then they watched it speed up about 50% as the moon's modest gravity took control. Mathematical analysis showed that Lunik II followed the proper curve to crash near the center of the lunar disk.

The Russians estimate that when Lunik hit, it was traveling at about 7,400 miles per hour. A future moon vehicle will have to be slowed almost to parachute-jumper speed if it is to land gently enough on the moon's surface to survive the impact and report back what it finds.

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