Sep 10 1974
From The Space Library
Pioneer 10 data returned from the 3 Dec. 1973 encounter with the planet Jupiter appeared to support the theory that Jupiter was a spinning ball of liquid hydrogen without a detectable solid surface, NASA reported. At most, the planet probably had only a small rocky core deep below the heavily clouded atmosphere. Jupiter's great red spot probably was the vortex of a gigantic storm that had raged along a 40 000-km front for 700 yrs.
Analyses by NASA experimenters and other scientists had shown that the Pioneer 10 information, the first measurements made from closer than the earth, contradicted some previous theories and verified others. As early Pioneer 10 reports had indicated [see 25 Jan., 2 and 9 April], Jupiter's turbulent interior was much hotter than expected, its magnetic field much larger than some predictions, and its radiation belts far more intense. The planet was a source of high-energy particle radiation, the only one in the solar system besides the sun. In its atmospheric circulation patterns, cyclones and anticyclones (ascending and descending) were stretched around the planet, rather than being circular as on the earth. This "weather-stretching," probably caused by heat radiation from the planet's interior and its 35 200-km-per-hr rotation speed, ac-counted for Jupiter's planet-girdling, alternating brown-red and gray-white cloud bands.
Density of the four largest moons decreased from the density of rock for the innermost Io and Europa to the density of a water-ice and rock mixture for the outer Ganymede and Callisto. Io had a tenuous atmosphere. Ganymede was known to have an atmosphere and the other two large moons probably had also.
Meanwhile Pioneer 11, the sister spacecraft launched 5 April 1973, was drawing toward Jupiter for its December flyby, before going on to Saturn. (NASA Release 74-238)
Safety was of prime importance to NASA management and NASA-Soviet joint working groups planning the Apollo Soyuz Test Project mission, Dr. James C. Fletcher, NASA Administrator, said in a letter to Sen. William Proxmire (D-Wis.) . The response to a Sen. Proxmire letter expressing concern for ASTP crew safety in light of past failures of the Soyuz and Salyut spacecraft explained that NASA had requested and received from the Soviets a detailed explanation of the Soyuz 11 (6-30 June 1971) failure, in which three cosmonauts were killed, and of the test program to correct the problem. NASA officials had also asked for information on the 26-29 Aug. Soyuz 15 mission, which ASTP technical personnel were expected to discuss during joint meetings 9-23 Sept. (Letter, Proxmire to Fletcher, 3 Sept 74; letter, Fletcher to Proxmire, 10 Sept 74)
The Air Force Systems Command's Arnold Engineering Development Center (AEDC) announced that it had refined computerized wind-tunnel techniques for predicting aircraft loss-of-control characteristics. AEDC correlated wind-tunnel data from a model F-15 aircraft mounted on a computer-controlled support with NASA drop-test data of a remotely con-trolled model. The computer predicted model response, such as stalls, to forces acting on it; activated the high-pitch rig to place the model in the appropriate position; and checked the prediction. This use of the computerized mounting system was the first without a human in the control cycle. (ASFC Release OIP 174.74)
10-12 September: California Institute of Technology scientist Charles T. Kowal discovered a possible 13th moon of Jupiter. In photos taken with the Hale Observatories' 122-cm Schmidt telescope at Mount Palomar, Calif., Kowal detected a 10- to 16-km moon as a pinpoint of reflected light 11 million km from the planet.
Photos taken 22 Sept. from the Univ. of Arizona's Steward Observatory and again 15 and 16 Oct. from Mount Palomar supported Kowal's findings. Dr. Kaare Aksnes of the Smithsonian Astrophysical Observatory determined the object belonged to the intermediate group of moons orbiting Jupiter at a distance of about 11 million km. (Alexander, LA Times, 20 Sept 74; Sullivan, NYT, 23 Oct 74,19)
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