Sep 4 1976
From The Space Library
4-8 September: Soviet news agency Tass reported the successful touchdown of the Viking 2 lander, adding that no data were coming from the lander "owing to failures in the Viking station's orbiting vehicle" that relayed lander communications to earth. (FBIS, Tass in English, 4 Sept 76)
As the long-awaited picture transmission from the Viking 2 landing site on Mars finally appeared at JPL, scientists were surprised to see rocks and more rocks in the Utopia region where they had expected steep sand dunes. Boulders were so numerous that driving a vehicle across the Utopia plain would be a challenge, Walter Sullivan wrote in the NYT. The scientists had hoped that the damper climate at the Viking 2 site might give more definite clues to organic life than the ambiguous reports from the Viking 1 lander experiments. They said they were delighted with the clarity of the photographs and the speed with which they were transmitted once the communications problem was solved. A tilt in the horizon appearing in the pictures meant either that one footpad of the lander was resting on a rock (according to Dr. Thomas A. Mutch, head of the surface-imaging experiment), or that the lander was on a slope (according to Project Manager James S. Martin, Jr.). Martin expressed concern about getting the second lander back on schedule after the difficulties it had encountered on descent. Although communication had been reestablished with the orbiter's main antenna after an unexplained stability problem had pointed its transmitters out of earth's range for about 12 hr, the lander might have suffered from a rocky landing when one shock absorber failed to function. An apparent tear was visible in the rim of the 76.2-cm aluminum dish on the Viking 2 lander, which Martin said probably resulted from the landing, but did not affect the radio signals to earth. Only direct communication with the lander would show whether damage had occurred to the body and its electronics systems. Dr. Carl Sagan of Cornell Univ. pointed out that both Viking landing sites had been chosen purposely "for their blandness," as free as possible from geological hazard; the rocks visible in the Viking 2 transmission were evidence of "an enormous exuberance of geological processes." Meanwhile, two of Viking 1's three biological instruments repeated their samplings of Mars soil from the plain of Chryse, with ambiguous results. The experiment that used' nutrients to detect life processes in the soil registered about the same number of radioactive counts (suggesting that the nutrient was being metabolized) as the first trial had. The photosynthesis detector registered only a third as much activity as the first sample, however.
The NYT pointed out that the Viking 2 lander would deploy its instruments in an environment different from that of Viking 1. Utopia, nearer the Martian north pole than Chryse, was expected to have a layer of water-containing permafrost underlying the surface; as the Martian summer was at its warmest in the Utopia region, scientists hoped for a better chance of life-identifying experiments at the Utopia site. Exobiologists had noted that, if Viking 2 results were more suggestive of life, they would feel encouraged; if the results were the same as those from Viking 1, this at least would show that the first reports were reliable. (NYT, 5 Sept 76, 1, 4-5; W Star, 5 Sept 76, A-1; W Post, 5 Sept 76, A-1)
An editorial in the NYT said the Viking engineers from government and private industry had needed luck to achieve two successful landings in two attempts; luck would have been inadequate without the "superb design and technical foresight" that had anticipated and forestalled many problems. (NYT, 6 Sept 76, 14)
Project Manager Martin reported 5 Sept. that what had appeared to be a tear in an antenna was probably dirt, spattered up when Viking 2 landed. The successful uncaging of the Viking 2 seismometer met with cheers from the geophysicists on the project who had been marking time since the Viking 1 instrument failed to unlock. Dr. Nafi Toksoz, a seismologist from MIT, said that lack of data from more than one point on Mars would make triangulation (and precise location of seismic disturbances) impossible, but even one instrument might answer questions about the nature of the planet's interior and the level of tectonic activity. He predicted that Mars would be "more active than the moon and less active than the earth." (W Star, 6 Sept 76, A-3)
As Viking 2 prepared to reach for soil samples, project scientists speculated on the possibility of mobile landers to explore the terrain and collect samples for study on earth. Dr. Elliott C. Morris of the U.S. Geological Survey said he felt like a child with nose pressed against a candy-store window, the "goodies forever beyond his reach." Like the Soviet Lunokhods that moved about on the moon, Mars landers with wheels or tractor treads could be set down in a relatively flat area and sent into mountains, canyons, and craters far more dramatic than similar features on earth. Project Manager Martin noted that such a mission could be launched in 1981 to land on Mars the following year: a backup lander in storage at Martin Marietta's Denver plant could be modified to make it mobile, and a spare orbiter was in storage at JPL, control center for the Viking missions managed by LaRC for NASA. Walter Sullivan of the NYT commented that the vivid detail in the panoramas transmitted from the cameras on the two landers had given the viewers the urge to go on over the horizon to see what lay beyond. (NYT, 7 Sept 76, 21)
The first weather report from the Viking 2 lander disclosed that Mars weather was almost the same in the northern latitudes as in the tropics this time of year, except that winds in the northern regions shifted more often. Dr. Seymour L. Hess of Fla. State Univ., leader of the Viking weather team, said the findings were as predicted, the winds changing in patterns similar to those in similar regions on earth. Bitterly cold temperatures on the Utopia plains-warmer than at Chryse, where the nights were longer-were no colder than Arctic or Antarctic temperatures at night on earth. The soil at Utopia appeared red in the Viking 2 photographs, but not as red as the surface at Chryse. The red color resulted from oxidation of iron in the Martian soil, which had an iron content of 14%, richer in iron than almost any soil on earth. The Viking scientists theorized that the paler soil at Utopia resulted from the presence of water, which would wash out some of the redness by forming hydrates or sulfates with other minerals in the soil. (W Post, 8 Sept 76, A-7)
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