Nov 3 1973
From The Space Library
The Skylab 4 launch crew successfully completed a simulated launch of the Saturn IB booster at Kennedy Space Center. The booster was scheduled to lift the Apollo command and service module and crew members Gerald P. Carr, Dr. Edward G. Gibson, and William R. Pogue into orbit Nov. 10 to dock with the Orbital Workshop (launched May 14) and begin NASA's third manned Skylab mission. Following the perfectly timed simulation, the fuel was drained from the launch vehicle and preparations for the final countdown were begun. (AP, B Sun, 11/3/73, A7)
France had begun work to hold future nuclear tests underground at two uninhabited atolls in the Pacific, French Adm. Christian Claverie said in Papeete, Tahiti. French nuclear tests previously had been conducted above the French-governed Tahitian atoll Mururoa, against international protests. (UPI, NYT, 11/4/73, 77)
November 3-13: NASA'S Mariner 10 (Mariner-J) Venus-Mercury probe was launched into a parking orbit from Eastern Test Range at 12:45 am EST by an Atlas-Centaur Dl-A launch vehicle. After a 25-min coast, a 130-sec burn of the Centaur engines injected the spacecraft into a heliocentric orbit that would allow Mariner 10 to pass within 5300 km (3300 mi) of Venus Feb. 5, 1974. Using the gravitational field of Venus to change the speed and flight path of the spacecraft, Mariner 10 would travel toward a March 29 encounter with Mercury, approaching the sun more closely than any other planetary mission. Mariner 10 would be the first spacecraft to use gravity assist in a dual-planet mission and the first to explore Mercury. The primary objective was to measure Mercury's environment, atmosphere, surface, and body characteristics and to make similar investigations of Venus. Secondary objectives were to perform experiments in the interplanetary medium and to obtain experience with a dual-planet gravity-assist mission. The seven experiments aboard the octagonal 503-kg (1108-1b) space-craft included a TV camera and an infrared radiometer to investigate the planet's surface; plasma science experiment, charged particle telescope, and magnetometer to investigate the environment around the planet and the interplanetary medium; dual-frequency-radio science experiment and ultraviolet spectrometer to measure characteristics of the Mercury neutral atmosphere and ionosphere if they existed; and celestial mechanics experiments to measure planetary mass characteristics and test the theory of relativity. All experiments had been designed and selected for their Mercury scientific objectives but also would obtain important data at Venus and during the cruise phases. The Tidbinbilla, Australia, tracking station was unable to maintain command lock with the spacecraft following spacecraft injection. Acquisition of the star Vega by the spacecraft Canopus tracker also was delayed, but two-way communications were established within an hour and, after repeated commands, Vega was acquired. Solar panels, high-gain and low-gain antennas, and plasma science and magnetometer booms were deployed. On Nov. 4-5 four moon and three earth TV picture mosaics were completed. By Nov. 6 the spacecraft was 1 394 000 km (866 000 mi) from the earth, traveling at a speed of 4.32 km (2.68 mi) per sec. All science experiments except the infrared radiometer and electrostatic analyzer had been turned on. The scanning electron spectrometer portion of the plasma science experiment was not operating properly and the problem was being analyzed. Four trajectory correction maneuvers were scheduled during the mission. The first, Nov. 13, successfully adjusted the flight path for closest approach to Venus on Feb. 5, 1974, as planned. A second would be made Jan. 18, 1974. On Feb. 9 and March 1, 1974, after the Venus encounter, maneuvers would target the Mariner 10 to pass Mercury at 1000-km (620-mi) altitude. The Mariner program, including mission operations and tracking and data systems, was managed by Jet Propulsion Laboratory under the direction of NASA'S Office of Space Science. Lewis Research Center, with contractor General Dynamics Corp. Convair Div., was responsible for the launch vehicle. Previous missions had been made to Mars, including Mariner 4, 6, 7, and 9 (launched Nov. 28, 1964; Feb. 24, 1969; March 27, 1969; and May 30, 1971). Mariner 9 had been the first spacecraft to orbit a planet other than the earth. All others had been flyby missions. (NASA prog off; JPL Release 673)
November 3-January 9, 1974: NASA'S Pioneer 10 interplanetary probe (launched March 2, 1972) became the first spacecraft to reach Jupiter during a two-month encounter, returning new findings about the giant planet and continuing toward Uranus and eventual exit from the solar system. November 3-December 3: Encounter operations were begun Nov. 3 by Ames Research Center controllers and scientists and on Nov. 4 Pioneer 10 began sending photopolarimeter images of Jupiter to the earth three to eight hours a day.
By Nov. 6 the spacecraft, 25 000 000 km (15 500 000 mi) from Jupiter, had begun measuring the planet's atmosphere above Jupiter's orange-and-blue-striped cloud tops and the characteristics of particles making up the dense clouds. On Nov. 8 the spacecraft crossed the orbits of Hades and Poseidon, the first two of Jupiter's outer moons, and on Nov. 9 and 11 it crossed the orbits of Pan and Andrastea. At a Nov. 19 press briefing at ARC Dr. John E. Naugle, NASA Associate Administrator for Space Science, said that low temperature in that area of the solar system slowed evolution and scientists hoped to find objects not very different from what they were at their formation. "The passage of Pioneer 10 past Jupiter also marks the gateway to the exploration of the outer solar system. This is an exploration which is critical if we truly want to understand the formation and evolution of our solar system." Dr. William H. Kinard, Langley Research Center scientist, said that Pioneer 10 had encountered 100 times more space dust than expected during the journey between the Asteroid Belt and Jupiter. He expected that 30 times more particles would be detected as the spacecraft neared Jupiter. Pioneer 10 crossed the orbits of Jupiter's moons Demeter, Hera, and Hestia Nov. 22 and was 11 400 600 km (7 084 000 mi) from Jupiter.
By Nov. 25 a charged particle detector aboard the spacecraft had begun to show traces of particle radiation. Preliminary indications were that the probe was beginning to cross into Jupiter's magnetosphere, estimated to be 20 times stronger than the earth's. The planet's radiation belts contained particle concentrations up to 1 million times higher than the earth's Van Allen Belt and were considered by some scientists to be extremely dangerous to the spacecraft's electronics. At a distance of 8 336 400 km (5 180 000 mi) from Jupiter, spacecraft instruments began returning pictures of Jupiter's great red spot. The final spacecraft-attitude change before encounter was made Nov. 26 and a 24-hour day of imaging and polarimetry began.
At 3:30 pm EST Nov. 26 Pioneer 10 successfully crossed Jupiter's bow shock wave at a distance of 7 709 000 km (4 790 000 mi)--with great turbulence when the solar wind hit Jupiter's magnetic field. The spacecraft was unaffected by the turbulence but data from 6 of its 11 instruments changed dramatically. Solar wind speed abruptly decreased to half the normal velocity and solar wind temperatures rose sharply. On Nov. 27, at a distance of 6 760 000 km (4 200 000 mi) from Jupiter, the spacecraft crossed into the planet's true magnetic envelope, the region of interplanetary space into which the solar wind could not penetrate. Pioneer 10 crossed the magnetopause, entering the magnetic field for the first time at 3:30 pm EST.
At a Nov. 29 press briefing ARC scientists said new data had shown the reach of Jupiter's magnetic field to be greater than predicted. It stretched more than 13 000 000 km (8 000 000 mi) in diameter and its strength was 40 times that of the earth's magnetic field. Its direction was south, rather than north as predicted. The strength of the magnet. ism at 6 400 000 km (4 000 000 mi) from the planet seemed to rise and fall in a regular 10-hour phase, possibly because of the planet's rotation. Jupiter's mass was also found to be greater than estimated and the spacecraft was being drawn toward Jupiter faster than planned; it would arrive at its closest approach two minutes earlier than predicted.
On Nov. 30 Pioneer 10 recorded a sharp drop in magnetic and radiation measurements, indicating disappearance of the magnetic field. Eleven hours later the spacecraft again crossed the magnetopause, which had apparently been driven toward the planet by a disturbance in the solar wind. At 1 427 500 km (887 000 mi) from the planet, the space-craft entered Jupiter's dipole magnetic field. Preliminary data indicated that the outer portions of Jupiter's magnetic field did not rotate with the planet and were more flattened than the earth's field. Also, the magnetic dipole center was appreciably offset, both radially and toward the north from the center of the planet. The magnetic axis was tilted from the spin axis. Pioneer 10 crossed the orbits of Jupiter's innermost moons-Callisto, Ganymede, Europa, and Io-Dec. 2-3. As it came within 446 000 km (277 000 mi) of Ganymede, the infrared radiometer indicated the moon's surface temperature was 125 K ( -235°F). Six hours before its closest approach to Jupiter the probe entered the dangerous region of intense radiation and, soon after, the imaging system ceased return-ing picture data. Radio commands switched the system back to normal operation within 30 minutes, however. The press later reported that NASA attributed the mishap to an unidentified flight control room guest who had inadvertently pressed against a cathode ray display, pushing a button that cut out eight instruments.
December 3-11: As the gold and silver spacecraft approached Jupiter and radiation intensity increased 10-fold every two hours, reaching 65 million ev 90 min before periapsis, tense scientists paced the floor of ARC'S Mission Control with fingers crossed. At 9:25 pm EST Dec. 3, after a flight of 641 days and 826 000 000 km (513 000 000 mi), Pioneer 10 sped past Jupiter at an altitude of 130 000 km (81 000 mi), traveling 155 140 km per hour (96 400 mph), the fastest speed ever achieved by a man-made object. The spacecraft's 11 instruments sent back readings and pictures that came in loud and clear, taking 46 minutes to reach a jubilant team on earth. "Needless to say, we're elated," Dr. John Wolfe, Pioneer Project Scientist, told cheering newsmen.
The Washington Post later described the scene at ARC: "So deluged were Pioneer scientists with transmissions of the spacecraft's instru-ments, they were literally changing their minds about Jupiter's physics and chemistry every hour." Dr. James C. Fletcher, NASA Administrator, said, "Some of us have been looking through telescopes at Jupiter since our early teens. This is more than we ever dreamed of." The spacecraft suffered no apparent failures and continued to function as planned. However, preliminary estimates of radiation belt parameters and observed effects on the spacecraft and instrumentation indicated that the margin of survival had been small. As Pioneer 10 flew by Jupiter, the spacecraft was accelerated and slung by the planet's gravity into a new trajectory that would take it past the orbits of Saturn, Uranus, Neptune, and Pluto and, traveling at a constant 40 000 km per hr (25 000 mph) , out of the solar system toward the constellation Taurus. Pioneer 10 would be the first spacecraft to leave the solar system.
By 7:00 pm EST Dec. 4, it had traveled nearly 1 600 000 km (1 000 000 mi) beyond Jupiter. December 11-January 9: ARC Mission Control ended Jupiter picture-taking Dec. 11 and returned to routine interplanetary operations. The spacecraft recrossed the bow shock wave Dec. 12 and continued into interplanetary space. By Dec. 14 the spacecraft was 10 881 000 km (6 761 000 mi) from Jupiter, traveling at 83 525 km per hr (51 900 mph) toward the edge of the solar system. Preliminary findings from the encounter included the discovery of an ionosphere (implying a tenuous atmosphere) surrounding Jupiter's moon Io, detection of helium in Jupiter's atmosphere, new density measurements of the entire Jovian system that would affect current theories on the formation of the universe, and new temperature measurements of Jupiter that indicated little difference between average day-time and nighttime temperatures.
Pioneer 10 was expected to continue collecting and returning data until it reached the orbit of Uranus in 1980, almost 3 200 000 000 km (2 000 000 000 mi) from the earth. Data returned would determine whether the second Jupiter probe, Pioneer 11 (launched April 5 and crossing the Asteroid Belt since August), could safely be retargeted closer to the planet. The Pioneer 10 mission was officially adjudged a success Jan. 9, 1974. The Pioneer program, begun in 1958, was directed by ARC. Pioneer 6 and 7 (launched Dec. 16, 1965, and Aug. 17, 1966, to study the heliocentric space environment) and Pioneer 8 and 9 (launched Dec. 13, 1967, and Nov. 8, 1969, to study interplanetary phenomena) continued to supply data from heliocentric orbit on solar plasma, magnetic and electric fields, and cosmic rays. (NASA prog off; ARC Release, 11/6/73; NASA Releases 73-243K, 73-256, 73-279; Wilford, NYT, 11/25/73; 11/30/73, 1; 12/4/73, 1; 12/5/73, 13 ; O'Toole, W Post, 12/4/73, Al ; AP, W Star-News, 11/28-29/73; AP, B Sun, 12/3-4/73; Miles, LA Times, 12/4/73; 12/6/73)
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