HAZARDS OF LUNAR FLIGHT FORESEEN

Press, Volume CVIII, Issue 31866, 19 December 1968, Page 8

HAZARDS OF LUNAR FLIGHT FORESEEN

The risks of flying round the moon, as the Apollo 8 astronauts will do late this month, are considerably greater than merely flying through space in earth orbit.

But many safety elements are built into the round-the-moon flight so the astronauts will be able to cope with most emergencies.

The craft will be in a “fret return" trajectory—if left t< itself it will loop around th' moon and return to earth Except while in moon orbi —when the astronauts will de pend on their main engine t( eject them from that orbit—there is little danger that thr craft will get stranded ii space. All vital systems are “redundant," meaning the same functions can be accomplished in at least one other way if one system fails. The main danger on the mission is likely to be the long intervals required to return to earth in an emergency. While in moon orbit, the astronauts will be more than 200,000 miles from earth. In all earth orbital flights it has been theoretically possible to return to earth in about half an hour to three hours. During their moon orbit the Apollo 8 astronauts would require more than two days to return to earth.

At most points during their journey to the moon the astro nauts could, turn their craft around, fire their main en ■,’ine, and head back to erath The required time for their .•eturn would then depend on .heir distance from earth. If the third stage of the Saturn rocket fails to re gnite, making it impossible o boost the Apollo 8 capsule >ut of earth orbit, the astro tauts would simply remain ir tarfh orbit for about 10 days They would carry out a variety >f experiments so as to ob ain maximum scientific bene it from the flight. Officials of the United States National Aeronautics ind Space Administration have worked out alternate plans to be placed in effect if some technical failure during the early part of the flight prevents the planned around-the moon flight. The entire flight will be conducted in steps called “platea'us” or “commit points." At each such plateau

a thorough check of craft and crew will be undertaken, and a decision will be made on whether to proceed with the next step. Should the Saturn third stage fire so as to eject the craft from earth orbit but with nsufficient momentum to reach the moon, an alternate flight plan calls for insertion of the carft in a 4000-mile ugh earth orbit. After three or four such orbits, the craft would be brought down to the 100-to--200 mile altitude commonlv used for manned orbital flights. The craft would maintain that altitude for 10 days. Still another plan calls for allowing the craft to reach an altitude of up to 60,000 miles if its momentum is strong enough, and then return to earth. Finally, the craft can be allowed to loop round the moon and return to earth, without attempting any moon orbits.—(U.S.l.S.)