Pioneer 10 Passes Jupiter, Will Leave Solar System
By John Noble Wilford Special to The New York Times
Pioneer 10 spacecraft passes within 81,000 mi of Jupiter on Dec 3, sailing safely past planet's hazardous radiation belts and transmitting color photographs and mass of scientific data; extreme pull of Jupiter's gravity accelerates spacecraft and swings it past planet on new trajectory, which should make it 1st man-made object ever to leave solar system; Pres Nixon lauds mission as 'impressive technical scientific achievement,' which demonstrates 'man's ability to explore the heavens is on the threshold of the infinite'; spacecraft transmits photographs, reptdly clearer than any previous pictures of Jupiter, which reveal planet's Great Red Spot as well as its cloud-covering of cold ammonia flowing in bands of many colors; radioed data include measurements of Jupiter's radiation belts, magnetic field, temperatures and atmospheric composition; scientists rept 1st confirmation of helium existing on Jupiter, discovery considered important to cosmologists attempting to explain chem of solar system and universe; rept spacecraft apparently survived Jupiter's heavy radiation doses without degradation, and that radiation levels reached peak 15 mins before Pioneer's closest approach; spacecraft passed within 277,000 mi of Ganymede, largest of Jupiter's 12 moons, and transmitted information, which indicates Ganymede's surface is coated with water ice and has temperature of -235 degrees Fahrenheit; encountered steadily increasing amount of radiation after passing Europa, closest of Jupiter's satellites; temporary malfunction of spacecraft's imaging system results in loss of nearly 1 hr of data, including photograph of Io, another of Jupiter's moons; flight controllers are unsure whether problem was random malfunction or somehow related to radiation bombardment; Dr J A Van Allen, project scientist, says Jupiter's magnetic field seems to be slightly offset at a slight degree from those most commonly predicted and that it apparently is shaped like a broad, thick disc as opposed to spherical and symmetrical shape of earth's magnetic field; estimates disc is spun out out several million miles, but is only 176,000 mi thick--4 times as thick as planet's radius; spacecraft traveled further and faster than any previous manmade object during journey to Jupiter--1 of most important scientific moments in 16-yr US space program; chart compares mean distance from sun, diameter, mass, surface gravity, rotation period and number of moons of Jupiter, Mercury, Venus, Earth, Mars, Saturn, Uranus, Neptune and Pluto; diagram of Pioneer's trajectory to Jupiter and its solar system trajectory depicts assumed shape of planet's magnetic field and assumed limit of its disturbance in interplanetary medium; shows direction of Jupiter's orbit around sun and direction away from Jupiter toward earth and sun