Jul 17 1976
From The Space Library
17-19 July. Project scientists said the high proportion of argon in the Mars atmosphere might damage the life-detection instruments on Viking 1. In March 1974, a spectrometer pump on a Mars-bound spacecraft failed to work properly and Russian scientists concluded the problem was caused by argon, an element reluctant to form chemical compounds; the Russian pump apparently could not handle the high argon content of the Mars atmosphere. Viking 1's gas-chromatograph mass spectrometer contained filter material to screen out carbon dioxide and carbon monoxide in the search for organic compounds in Mars air and soil samples, which would be heated in the instrument to produce gas for analysis by the chromatograph; the high argon content might interfere with the readings. (NYT, 17 July 76, 24)
JPL flight directors were checking out the instruments on Viking 1 for its Mars landing scheduled for 20 July. Immediately upon landing, the spacecraft would measure air temperature and pressure and wind speed and direction, and would detect any interior motions of the planet such as moving lava or shaking of the crust. It was also scheduled to take 2 photographs, one downward to record the terrain of the landing site and the other a panorama shot to show the general surface of Mars. Life detection experiments would not begin until about a wk after the landing. (W Post, 18 July 76, A-10)
Commands from JPL to turn on the $153-million instrument package to be landed by Viking 1 on the Plains of Chryse took between 17 and 18 min to reach the spacecraft nearly 346 million km away from earth. First spacecraft responses to the signals indicated the instruments and navigational equipment were in working condition. Landing was scheduled for 8 am EDT on 20 July; Viking 1 would separate early in the morning into 2 components, 2300-kg orbiter and 590-kg lander. The orbiter, powered by purple solar cells on panels, would remain in orbit to serve as a radio relay for the lander and to photograph nearly half the Martian surface over the next 12 mo. The lander, powered by an atomic battery, would coast for about 3 hr, slowed by a parachute and braking engines, and land on 3 aluminum legs at about 8 kph, more gently than most parachutists land on earth. (W Post, 19 July 76, A-3)
Odds were heavily against existence of any form of life on Mars, said a Washington Post editorial, and against Viking 1's finding evidence of it even if it were there. The Viking flights were "in some ways more remarkable an undertaking" than the Apollo flights because the spacecraft was on its own with no humans to correct errors and a sizable time lapse between sending and receipt of radioed instructions. The mission, said the Post, was "already a stunning accomplishment." (W Post, 20 July. 76, A-16)
The Viking spacecraft was "a breed apart," the Wash. Post reported, as different from previous spacecraft "as a Cadillac from a Pinto." Almost nothing on the lander had own in space before; almost everything had to be built super-small to save weight. As the first U.S. spacecraft to land on another planet, the Viking had to be designed to withstand chemical and heat sterilization to avoid contaminating Mars with earth organisms. The tape recorder, for instance, had to be made of bronze coated with phosphor, because no plastic tape could have survived the heat. (W Post, 20 July 76, A-2)
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