One of three small ovens on an experiment aboard NASA's Viking 2 Lander apparently did not operate during recent checkout tests of the instrument.

A study of the data from the tests showed that oven 1 either failed to heat or that data from timing device is faulty. Telemetry from the timer indicates whether or not an oven is on.

The problem with the oven did not affect the operation of the experiment which worked well throughout the test.

Project officials are assuming that oven 1 did not turn on but will not be sure until the operation of the oven, on Mars, with soil sample.

The ovens will heat Martian soil samples to 932`F to identify chemical processes in the soil and determine if organic materials exist in the soil that would indicate the possibility of life forms on the planet, either in the past or at present.

The experiment is separate from the three Viking biology experiments which will make direct tests for life in the Martian soil.

The possible loss of one oven means that only two soil samples will be tested instead of three and will not affect the operation of the experiment.

The experiment's instrument is Gas Chromatograph Mass Spectrometer, complex device used in laboratories on Earth for molecular analysis. The compact flight version of the instrument was specially designed for the Viking project.

The experiment will also identify modules in the Martian atmosphere but this part of the experiment does not require the ovens.

The two Viking spacecraft, launched in August and September, 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 wil1 descend during the first week in September. Each Lander carries full compliment of identical experiments.

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