Authentic Science Fiction Monthly, No. 67 — page 89: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

AUTHENTIC SCIENCE FICTION circum-lunar orbits will have studied and photographed promising “landing grounds” and even made a few test drops to judge their solidity and nature, it is evident that a horizontal landing on even the most promisingly level stretch would be foolhardy. In addition, the expedition has to take off after its stay, and that take-off must be made vertically. With no cranes around to raise the ship’s nose, the task would be impossible. Thus we can say that the landing will be made vertically, and design our vehicle accordingly. Having broken away from the circum-lunar orbit in which the return journey ships and fuel have been left, the landing craft is put into a closed orbit close to the lunar surface. From this intermediate orbit the final approach will be made. Knowing the elements of the orbit, computed from observations by the methods of celestial mechanics, it is possible to predict future positions and velocities. The computer-member of the crew, possibly still in the circling ships above, then calculates the rocket-blasts necessary to bring the landing craft to a dynamic rest at any height above the lunar surface. 88 This computation can be carried out leisurely, since the landing craft is in a stable orbit and is not consuming any fuel. In fact, the craft may remain a considerable time in this orbit, making many circuits of the Moon, until the computer is satisfied with the accuracy of his calculations. His firing pro- gramme is now given to the pilot, who brings the ship to the rest-point above the surface of the Moon. At that point the vehicle will have its rocket motors firing down- wards and the pilot, using a radar altimeter, will then ease the ship vertically down- wards to a landing. It is seen then that only in the final manceuvre is the ship left completely to the skill of the pilot in making on-the-spot decisions. Just before contact with the ground, the motors are cut and the ship falls freely the rest of the way. Arthur Clarke has pointed out that even today helicopter undercarriages have been made strong enough to take rates of descent of 40 feet a second. On the Moon, where the surface gravity is one-sixth that of the Earth’s, this strength of undercarriage could withstand a fall from 160 feet. Thus, even if there conmcloooks.com