Oct 21 1975
From The Space Library
Goddard Space Flight Center had awarded a $45.8-million contract to RCA Astro-Electronics Division for design and production of eight third-generation Tiros-N spacecraft, the company announced.
Scheduled for launch in 1978, the 635-kg spacecraft would forecast weather 2 days in advance with accuracy equal to that of present 1-day predictions. RCA earlier had received a $16.6 million NASA contract for long lead-time items for the Tiros-N series, bringing the total cost of the satellites to $62.4 million. (SBD, 21 Sept 75, 259)
Jet Propulsion Laboratory and the Energy Research and Development Administration announced selection of 16 organizations to negotiate contracts for the development of low-cost solar cells for residential and commercial use. Twenty-two contracts, totaling approximately $12 million, would be awarded as part of the Low Cost Silicon Array Project managed by JPL for ERDA. Objective of the project was to create by 1985 an industrial capability of producing silicon solar cells or arrays at a market price of less than $500/kw. Cost to date had been $20 000/kw. The demand for solar cells was expected to increase from 100 kw annually in 1975 to 500 000 kw annually by 1985.
JPL negotiations included production of low-cost solar-grade silicon, economical production of silicon in large-area sheets suitable for use in solar cells, development of economical encapsulation materials and techniques for an array lifetime of 20 yr, and development of automated processes and facilities for low-cost production of arrays.
Future contracts would be negotiated to procure array modules for a series of ERDA-funded tests of photovoltaic systems, in cooperation with the Department of Defense to determine the technical feasibility of using photovoltaics for military applications, and in cooperation with Lewis Research Center for a similar civilian effort. (NASA Release 75-280)
22-25 October: Two unmanned Soviet probes, Venera 9 and 10, dropped landers to the surface of Venus after 4.5-mo journeys and relayed to earth through 297 million km of space the first photographs of the Venusian surface. The two main probes went into differing 2-dayperiod orbits about the planet. The Venera 9 lander functioned for 75 min in the atmosphere and 53 min on the surface, and the Venera 10 for 75 min in the atmosphere and 65 min on the surface.
The descent module of Venera 9 separated from the main spacecraft 20 Sept., 2 days before it reached the Venus atmosphere, which it entered at 11:58 pin EDT 21 Sept., landing on the surface at 1:13 am EDT Sept. 22. When the atmosphere had slowed the descent sufficiently, a parachute system had been deployed at about 50 km above the surface, and the lander studied the cloud layers and atmosphere during the rest of the descent. The lander modules had been built to withstand the hostile environment at the Venus surface, with temperatures that reach 500°C and pressures up to 100 times that of earth's atmosphere. Before landing, the modules had been cooled to -10°C to provide a reserve of cold temperature that would permit operation for about an hour before overheating. Venera 10, launched 14 June and following the same procedure, had separated from its orbiter 23 Sept. and had landed on Venus at 1:17 am EDT 25 Sept.
Venera 9, launched 8 June from the Baykonur cosmodrome, was the third Soviet spacecraft to make a soft landing on Venus: Venera 7 and 8, which landed on Venus in Dec. 1970 and July 1972, respectively, had transmitted technical data for 23 and 50 min, respectively, but did not carry cameras.
Pictures sent by the Venera 9 lander showed a rugged surface with sharp-angled and flat-surfaced rocks 30 to 35 cm across and some boulders. Pictures sent by the Venera 10 lander, which touched down 2200 km from the site of Venera 9, showed what seemed to be an older mountain formation with smooth rounded rocks. Soviet scientists had expressed amazement that both sites were bathed in light. The dense cloudcover that hides Venus from earth had been thought to keep the planet in perpetual shade. Dr. Arnold Selivanov, one of the TV system designers, said that they had "expected poor lighting conditions and built our instruments accordingly"; this is why they had received "good pictures... that can be used by newspapers without any preliminary processing." The horizon of Venus discernible in a corner of the Venera photos did not appear concave (ends bent upward), as had been expected as a result of the theorized distortion resulting from the planet's dense atmosphere. The apparent geological youth of the rocks on Venus "testifies to recent catastrophic processes like volcanic eruptions or earthquakes-we should say Venus-quakes-which took place recently," said Soviet mineralogist Dr. Aleksandr Basilevsky. "Venus apparently is internally active." This conclusion had affirmed American theory that Venus resembled earth in having a liquid core, a mantle, and a rocky crust.
Four Soviet scientists reviewing the Venera 9 and 10 program in an article in Pravda had summarized the descent-module findings: Temperature and pressure at the landing sites, 460°C and 90 atm, respectively; surface illumination, about 10 000 lux; local wind velocity at landing site, 0.4 to 0.7 meter per sec (Venera 9) and 0.8 to 1.3 meter per sec (Venera 10); natural radioactive elements in Venus rock, 0.3% potassium, 0.0002% thorium, and 0.001% uranium. Orbiting module findings were: Temperature of Venus clouds at upper boundary, about -35°C; cloud temperatures on nocturnal side, about 10°C higher; atmospheric temperature decreased with altitude, but local temperature elevations were observable at the 66 to 55 km level; Venus ionosphere was thinner than the terrestrial and closer to the surface; and the electron concentration on the daytime side was significantly higher than on the nocturnal side but about 10 times smaller than in the terrestrial ionosphere. Much of the information relayed from Venus had still to be processed.
Cameras in the orbiting spacecraft of Venera 9 and 10 had proceeded with photographing the dense cloudcover of Venus, their first pictures received 26 Sept. showing a panorama of more than 1500 km of the clouds circulating around the planet's equator. Scientists at the Deep Space Communications Center in Moscow said the pictures "confirm the presence of powerful streams of circulating flows in the planet's atmosphere, first detected on board the American probe Mariner 10 in February 1974." There was no indication, the Baltimore Sun commented, how long the two Venus mother ships would continue in orbit. (NYT, 23 Sept 75,1; 26 Sept 75, 1, sec. 4 p 7; FBIS 208, 210, 25 Sept 75; W Star, 23 Sept 75, A3; B Sun, 26 Sept 75, All; 27 Sept 75, A4; Defense/Sp Bus Daily, 23 Sept 75, 272; 28 Sept 75, 289; 29 Sept 75, 301; Pravda, 21 Feb 76, 3-4)
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