Sep 12 1976
From The Space Library
Vandals who damaged the moon rock on display at the National Air and Space Museum in Washington, D.C., were not successful in obtaining a piece of the rock, said the Washington Post. The lunar sample, a 40-gram triangular chuck of basalt, had been imbedded in a block of glass so that it might be touched by museum visitors; about 2 cubic mm had been chipped away and a missing corner of the triangle and a scratch over the surface had become visible in the single beam of light that illuminated the sample. NASA had sent experts to photograph the damage and to vacuum the exhibit area for any dust or small chips that might have come off the sample. Electronic security measures were being increased, and a fulltime guard had been stationed near the display, as a result of the incident. (W Post, 12 Sept 76, B-3; Av Wk, 27 Sept 76, 16)
As Viking 2's lander was preparing for its scoop-and-analyze sequence on the rocky Utopia site of Mars, the Viking 1 orbiter fired its engines to shift orbit around the planet in 40° longitude jumps each day for 9 days before taking over the relay of communications from the Viking 2 lander. Viking 2's orbiter would then begin a polar-orbital scan of Mars to search for traces of organic materials-carbon-based molecules found in all life forms on earth-not yet detected by Viking 1 experiments. Viking 1's lander would remain in standby mode after its weeks of testing at the Chryse site. Project scientist Dr. Gerald A. Soffen, commenting on the confusing results of the Viking 1 experiments (which hinted at the existence of life but offered no evidence of organic chemicals), said he had been prepared for the discovery of organic chemicals without life, but the suggestion of Martian life without organics was totally unexpected.
Just after 6 a.m. EDT on 12 Sept., the 3-meter arm of Viking 2 dug its first sample of Mars soil and dropped it into the hopper leading to three biology instruments. First cycle of the pyrolytic-release experiment began when the soil reached the test chamber, to be incubated in a carbon monoxide-carbon dioxide atmosphere containing a radioactive tracer; after 5 days, the atmosphere would be flushed out and the soil sample heated to vaporize any organic material. A detector would measure the radioactive carbon that had been ingested by any organisms. The gas exchange detector-looking for signs of photosynthesis in the dark would reveal the presence of organisms that might exhale gases such as oxygen or carbon dioxide through the night as well as in the daytime. (The first results of the same experiment on Viking 1 at Chryse had showed the soil was releasing six times as much gas as it would have in the absence of photosynthesis; a second trial had produced a signal a third as strong as the first, but still twice what it would have been if no photosynthesis were going on. Neither the readings nor their differences had been explained to everyone's satisfaction.) The third biological instrument-the labeled-release experiment-would add a nutrient liquid to the test chamber on Tuesday and monitor over 10 days the release of radioactive tracer from any metabolized nutrient.
A second soil sample would be used beginning Monday, 13 Sept., for an organic-chemistry analysis to detect carbon molecules, and for an x-ray fluorescence experiment to learn the composition of inorganic chemicals in the Mars soil.
Scientists believed chances of finding definite traces of life would be better at Utopia, where five times more water had been measured in the air than at Chryse. They also planned to reduce chances of ambiguity in the Utopia readings by conducting the photosynthesis search at night, and by moving a rock to take a sample of Mars soil that was shielded from the killing solar ultraviolet constantly impinging on the planet's surface and that was deeper than the sample taken at Chryse. (W Star, 12 Sept 76, A-14; W Post, 13 Sept 76, A-5; C Trib, 13 Sept 76, 6-16)
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