Second Viking Oven May Have Failed

One of three small ovens in an experiment aboard the Viking 1 spacecraft may not be working, similar to condition on Viking 2 reported last week. Both Vikings are enroute to Mars for the first U.S. attempt to land on the planet.

The ovens–three on each Lander–are designed to heat Martian soil samples to 500 degrees (932 degrees Fahrenheit) to release organic constituents in the soil for analysis by gas chromatograph mass spectrometer (GCMS).

During the in-flight test of Viking 2, test data indicated that one of the three ovens may not function on Mars. Project officials then examined prelaunch test results on the ovens on Viking 1 and found similarity in the data on one of the ovens, leading them to suspect second failure.

Project officials stated, however, that telemetry from monitoring device associated with the ovens may be faulty, and the final test will occur on Mars when soil samples are placed in the ovens.

Tests were conducted on both instruments prior to launch, using Bench Checkout Equipment. Detailed test data were also recorded. It was project practice to make detailed review of recorded test data only if malfunction was indicated. At the completion of these tests, no such indication had been observed. When the flight anomaly occurred, all recorded test data were analyzed. The results of this analysis show that the two ovens or their monitoring devices may have failed prior to launch, possibly during the final assembly process.

The loss of one oven on each experiment will not affect the operation of the instruments, but it will result in the analysis of two rather than three soil samples by each instrument.

The gas chromatograph mass spectrometer wi11 determine atmospheric constituents and search for organic material in the soil which could be evidence of biological or non-biological activity.

There is separate biology instrument aboard each lander that will perform direct search for life forms in soil samples.

The two Viking spacecraft, each consisting of lander and an orbiter, were launched in August and September, 1975. They will reach Mars on June 19 and August 7. The first lander will be detached from the Viking orbiter and descend to the surface in the first week of July. Lander 2 will descend during the first week in September. Each lander carries full complement of identical experiments.

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Astrobiology