Nov 13 1971
From The Space Library
U.S.S.R. announced Mars 2 and Mars 3 (launched May 19 and May 28 and scheduled to encounter planet Mars within two weeks) would attempt to put first man-made objects on "red" planet. Dr. Carl Sagan, Cornell Univ. astronomer, said Soviet scientists had told him Mars 2 and Mars 3 were equipped to land instrument probes. He said he understood they contained flammable material that would destroy any earth bacteria when probes completed investigation. (W Star, 11/14/71, A6)
November 13-15: Mariner 9, launched by NASA May 30, was inserted into elliptical orbit around Mars at 7:32 pm EST Nov. 13 after 15- min engine burn and became first spacecraft to orbit another planet in solar system. Orbital parameters were close to planned ones: 1398-km (868.7-mi) periapsis altitude, 12-hr 34-min period, and 64.5° inclination. Spacecraft propulsion system and attitude control systems per-formed flawlessly after 400-million-km (248-million-mi) journey. Mariner 9 would orbit Mars twice daily while photographing up to 70% of Martian surface in next three months.
Mariner 9 became the first spacecraft to orbit the planet Mars. The first photos of the planet were obscured by a dust storm but later pictures revealed sinuous rilles whose origin was puzzling. The valley above, 700 kilometers (435 miles) long, was photographed Jan. 22, 1972, in the Mars Rasena region. Such rilles might have been produced by collapse of the roof over subsurface lava flows. They raised the possibility of erosion by water in ancient Martian history.
First photos were obscured by dust storm but before end of month Mariner 9 had shown that Mars bulged at equator, was "rougher gravitationally" than expected, and probably had wide variety of rock compositions; instruments had detected small amounts of water vapor at south pole and warmer air pockets above pole [see Nov. 16-23]. Spacecraft also made man's first close photo of potato-shaped Martian moon Deimos [see Nov. 26- 27] and photos of moon Phobos [see Nov. 29-30]. First Mariner photos from orbit were broadcast live by national TV network, but detail was limited by dust storms that had raged on surface since September. Dr. Robert H. Steinbacher, JPL project scientist, said "We're hopeful that as the storm dies down we can get some good pictures of the dust settling to the surface. This is an unprecedented chance to watch changes in the Martian weather." He said that if cameras worked properly pictures would be 1000 times better than any earthbound telescopes had taken. On Nov. 14 spacecraft transmitted three sequences of TV pictures. Of more than 60 photos returned, only seven revealed surface features. Dust storm continued and atmospheric experts could see no sign of abatement. Dust obscuring planet was apparently very fine sand which high winds pushed to height of as much as 16 km (10 mi) above surface. On fourth orbit spacecraft successfully completed orbit trim maneuver at 9:44 pm EST Nov. 15. Maneuver changed orbital period of spacecraft to make it synchronous with Mars viewing period of Deep Space Station antenna at Goldstone, Calif. New orbital parameters were 1394-km (866.2-mi) periapsis altitude, 11-hr 57- min 12-sec period, and 64.34° inclination. Data from remote-sensing instruments confirmed earlier observations that carbon dioxide was major constituent of Martian atmosphere and also suggested possibility of "hot spots" on planet. Dr. Ellis D. Miner of JPL said sensor detected average temperature rise of 6.7 K (12°F) in area 24 km (15 mi) square below Mars equator. Temperature rise might indicate hole in cloud cover exposing mountain peak or plateau reflecting residual heat or evidence of internal source of heat on Mars. uv spectrometer data indicated dust storm was made up of fairly coarse-grained, sandlike particles. (NASA Proj Off; Wilford, NYT, 11/14-16/71; O'Toole, W Post, 11/14-15/71; W Star, 11/16/71, A4)
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