Buggy to the Moon

Even while Space Administration Chief James E. Webb was telling a congressional committee last week about two of the most promising methods that the U.S.

may use in its effort to land men on the moon, some of his technical advisers were favoring a third: LOR (lunar orbital rendezvous). Though LOR at first glance seems like a bizarre product of far-out science fiction, many scientists are already convinced that it will prove easier, quicker and perhaps cheaper than any other system for making lunar landings.

At present the National Aeronautics and Space Administration is planning to reach the moon by earth orbital rendezvous (EOR)--an effort that will require two advanced Saturn boosters, each with 6,600,000 Ibs. of thrust. One rocket will carry the crew and its Apollo capsule and place it in an orbit around the earth. The second will bring up the fuel, rocket engines and other gear needed for the remainder of the earth-moon trip. The two payloads will rendezvous on orbit and prepare for departure for the moon. If preliminary tests make this system look too difficult. Webb proposes to fall back on direct ascent, using a giant Nova booster with 12 million Ibs. of thrust to toss a manned spaceship to the moon without the complication of orbital rendezvous. In either case, the spaceship will land on the moon after braking its descent with retrorockets. then take off for the earth from the moon's surface, perhaps parking briefly in a lunar orbit before starting the long voyage home.

Branch Line. The LOR system will use different tactics. When the spaceship approaches the moon, it will burn a small amount of fuel in its retrorockets and nudge itself into an orbit about 100 miles above the lunar surface. Then, instead of descending, it will detach a small "bug" containing two of its three-man crew. The bug will have rocket engines, a communication system and a modest supply of fuel as well as "biological support" to keep the crew alive. After it separates from the orbiting spaceship, a brief burst from its engines will put it into an elliptical orbit that swoops down to ten miles above the moon's surface. As the bug approaches this low point, the crew will fire a final decelerating burst and--hopefully --make a gentle touchdown on a not-too-rugged or dusty spot.

Departure will reverse the procedure.

After exploring the nearby parts of the moon as thoroughly as their oxygen, supplies and equipment permit, the crew of the bug will blast off and rendezvous with the spaceship orbiting above them. After joining the two spacecraft and making everything shipshape, the reunited crew will boost themselves out of orbit and take off for the earth. The bug may be taken back to earth or abandoned on the lunar orbit.

The great advantage of LOR comes from weight-and fuel-saving at the moon end of the trip. A three-man spaceship capable of landing on the moon with enough fuel left to take off again and propel itself back to the earth, will have to weigh somewhere in the vicinity of 100,000 Ibs. The landing bug will be much smaller, probably weighing only 25,000 Ibs.. because it will not carry all the fuel, supplies and equipment for the full trip back to earth. Less fuel will be needed to land it on the moon and take it off again.

All these savings will be reflected many times over in the diminished size of the booster needed at the start of the voyage.

LOR enthusiasts estimate that a single advanced Saturn booster will be powerful enough to make the voyage direct, skipping the costly and difficult rendezvous in earth orbit.

All plans to land on the moon are necessarily uncertain. No manned satellite has yet approached another orbiting object, or even attempted to. The formidable problems of bringing two manned satellites together and making them join without damage are still far from solution, and new, unimagined difficulties are sure to arise before a dependable technique has been developed and tested. Plenty of space experts fear that many years will pass before the first successful rendezvous on earth orbit has been accomplished.

Rendezvous on a lunar orbit promises to be even more difficult.

The crews of satellites circling the earth will be in constant communication with ground stations and with each other, even when they are on opposite sides of the earth. Their orbits will be analyzed by computers and their positions reported accurately every few minutes. The crews will be told what to do to bring the satellites together in the most effective way. If an attempt at rendezvous fails, the crews can re-enter the atmosphere and hope to get home alive.

On Their Own. Astronauts trying to rendezvous on a lunar orbit will be on their own. There will be no friendly stations on the moon's hostile surface, no computers to analyze the orbits of the waiting spaceship or of the bug that is trying to join it. Unless the two are close together, their crews will not be able to see each other or communicate by radio; the moon's surface curves so sharply that a few hundred miles of distance will put each of them below the other's horizon. Theoretically they can communicate by relaying messages via the earth, but this cumbersome system is not likely to prove dependable.

Before attempting lunar orbital rendezvous, U.S. astronauts will have to make many practice steps. First will come rendezvous in earth orbit, the crewmen becoming proficient at bringing their satellite capsules together with help from the earth below. Then a spaceship will voyage to the moon, park itself for a while in orbit there and return to the earth. After that, a bug will leave the spaceship and make a practice rendezvous with it without trying to land. Only after this maneuver has been mastered by several successful trials will the first lonely bug attempt to land on the hostile moon.

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