Looking Outward Again

Although public interest in space has waned sharply since the moon landings, the U.S. is now engaged in perhaps the most ambitious exploration of the solar system since the start of the space age. At Cape Canaveral, NASA last week was preparing for the launch of the Skylab 3 mission, which may become the longest manned space flight. An unmanned U.S. craft, Pioneer 10, is closing in on Jupiter after a voyage of 20 months across more than half a billion miles of the solar system. Still another unmanned spacecraft, Mariner 10, is speeding toward a flyby of Venus and later will provide the first closeup view of Mercury--man's first two-planet survey with a single space probe.

For a while the Skylab mission seemed to be in trouble. Only four days before the Nov. 10 launch date, workmen at the Kennedy Space Center discovered hairline cracks around bolts on all eight stabilizing fins of the Saturn 1-B booster that is to launch the ferry ship toward a rendezvous with the orbiting space station. The cracks may have developed when the rocket's fuel tanks were filled, enormously increasing the weight on the fins. Exposed to Florida's salty air, the fins may have been weakened by corrosion. To avert a calamitous accident after liftoff, NASA officials ordered all the fins replaced with spares rushed in from the Saturn assembly facility at Michaud, La. Hopeful that the replacement would take only a few days, NASA rescheduled the launch for Nov. 15.

New Experiments. Astronauts Gerald Carr, William Pogue and Edward Gibson, a physicist, have been assigned a long list of new experiments. These range from opening carbonated beverages (to see if they bubble in zero G), to breeding gypsy moths (in hopes of mass producing sterile offspring to reduce the pest population on earth), to observing Comet Kohoutek, which will make its closest approach to the sun during the Skylab mission. For their stay in space, which may be extended to 80 days, the men will carry along some 200 Ibs. of extra food: beverages, catsup and several hundred little high-nutrition food bars (flavors: chocolate, vanilla and raspberry). If all goes well, NASA officials think that the mission could lead to the establishment of permanent space stations--and eventually to their use as launch pads for manned trips to the moon and the planets.

For the time being, the only interplanetary voyagers are robots like Pioneer 10. Approaching its maximum speed of 78,000 m.p.h.--faster than any previous man-made object--the spacecraft last week crossed the orbital paths of the three outermost of Jupiter's twelve moons. By Dec. 3, Pioneer will pass within 81,000 miles of Jupiter itself, then swing around the massive planet and be accelerated by its gravity to so high a speed that it will escape from the solar system entirely--the first spacecraft ever to do so. Before leaving Jupiter's vicinity, Pioneer will collect reams of data--on the Jovian atmosphere and turbulent cloud cover, on the mysterious Red Spot, on the planet's interior and surrounding environment--as well as take two-color closeup pictures of Jupiter and its inner moons. There is one possible hitch: Jupiter's intense radiation belts could destroy the probe's electrical circuitry. But NASA scientists are optimistic about Pioneer's prospects. "Even if we go in there and die," says Project Scientist John Wolfe, "we'll find out a hell of a lot of useful information."

Mariner 10 may also run into some unexpected difficulties on the way to Venus and Mercury. Shortly after launch on Nov. 3, controllers discovered that the three tiny heaters used to protect the spacecraft's camera system from the bitter cold of deep space had failed to turn on. On-board temperatures have dropped to -22DEG F. So far the twin TV cameras have survived. If they hold out, they will take as many as 5,000 pictures of Venus as the spacecraft approaches the cloud-covered planet next February. Then, swept around by the planet's gravity, Mariner will slow down enough to fall inward toward Mercury. (Without the gravity assist by Venus, a more powerful launch rocket or a smaller payload would have been needed.) By March Mariner will come within 621 miles of Mercury, a hot, dense planet that never appears as more than an indistinct blur in earthbound telescopes, and take some 2,500 pictures of it. They should show surface details of Mercury and remove some of the mystery about the planet closest to the sun.

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