Vance I. Oyama

Preliminary findings of the Viking gas exchange experiment and a model for Martian surface chemistry

Oxygen and CO2 were evolved from humidified Martian soil in the gas exchange experiment on Viking Lander 1. Small changes in N2 gas were recorded. A model of the morphology and a hypothesis of the mechanistics of the Martian surface are proposed.

Venus Lower Atmospheric Composition: Analysis by Gas Chromatography

The first gas chromatographic analysis of the lower atmosphere of Venus is reported. Three atmospheric samples were analyzed. The third of these samples showed carbon dioxide (96.4 percent), molecular nitrogen (3.41 percent), water vapor (0.135 percent), molecular oxygen [69.3 parts per million (ppm)], argon (18.6 ppm), neon (4.31 ppm), and sulfuir dioxide (186 ppm). The amounts of water vapor and sulfur dioxide detected are roughly compatible with the requirements of greenhouse models of the high surface temperature of Venus. The large positive gradient of sulfur dioxide, molecular oxygen, and water vapor from the clould tops to their bottoms, as implied by Earth-based observations and these resuilts, gives added support for the presence of major quantities of aqueous sulfuric acid in the clouds. A comparison of the inventory of inert gases found in the atmospheres of Venus, Earth, and Mars suggests that these components are due to outgassing from the planetary interiors.

A model of Martian surface chemistry

SummaryAlkaline earth and alkali metal superoxides and peroxides,γ-Fe2O3 and carbon suboxide polymer are proposed to be constituents of the Martian surface material. These reactive substances explain the water modified reactions and thermal behaviors of the Martian samples demonstrated by all of the Viking Biology Experiments. It is also proposed that the syntheses of these substances result mainly from electrical discharges between wind-mobilized particles at Martian pressures; plasmas are initiated and maintained by these discharges. Active species in the plasma either combine to form or react with inorganic surfaces to create the reactive constitutents.

The gas exchange experiment for life detection: The Viking Mars Lander

Abstract The Gas Exchange Experiment of the Viking mission accepts a sample of Martian soil, incubates this soil with nutrient medium, and periodically samples the enclosed atmosphere over this soil for the gases H 2 , N 2 , O 2 , CH 4 , Kr, and CO 2 . These gases are analyzed by an automated gas chromatograph, and the data are transmitted to Earth. The design of the experiment and the qualitative and quantitative changes, if any, of gas composition should allow conclusions to be made on the presence of life on Mars. Data and theory substantiating this approach are presented.

The search for life on Mars - Viking 1976 gas changes as indicators of biological activity

Gas compositional changes in the headspace of the Viking Biology Gas Exchange Experiment can originate from biological activity as well as redox chamical reactions, sorption and desorption phenomena, acid-base reactions, and trapped gas release. Biological phenomena are differentiated from the nonbiological gas changes by their dynamical qualities, notably by the ability of the M4 medium to sustain biological activity. Medium incompatibilities, with potential microbial types in soils, are demonstrated to be ameliorated by an incubation chamber design that provides thin films of medium around particulate soil masses and salt gradients when the soil is wet from below. Two phenomena in soils, the production and consumption of hydrogen and carbon monoxide, are coupled for a newly isolatedClostridium sp. A decrease in molecular nitrogen production by denitrifying organisms in the second and subsequent incubation cycles results from competitive nitrate utilization by anaerobic organisms. All soils tested from the cold, dry desert regions of Antarctica contain predominantly aerobic organisms while only six of the twelve soils respire using nitrate under anaerobic conditions. Although dry Antarctica soils are not the best simulations of Martian anoxic conditions, their responses show that long incubation times may be needed on Mars to demonstrate biological gas change phenomena.

The chemical activities of the Viking biology experiments and the arguments for the presence of superoxides, peroxides, gamma-Fe2O3 and carbon suboxide polymer in the Martian soil

The evolution of N2, Ar, O2, and CO2 from Martian soil as a function of humidity in the Gas Exchange Experiment are correlated with the mean level of water vapor in the Martian atmosphere. All but O2 are associated with desorption. The evolution of oxygen is consistent with the presence of alkaline earth and alkali metal superoxides; and their peroxides and the gamma-Fe2O3 in the soil can account for the generation of radioactive gas in the Labeled Release Experiment. The slower evolution of CO2 from both the Gas Exchange Experiment and the Labeled Release Experiment are associated with the direct oxidation of organics by gamma-Fe2O3. The Pyrolytic Release Experiments second peak may be carbon suboxide as demonstrated by laboratory experiments. A necessary condition is that the polymer exists in the Martian soil. We ascribe the activity of the surface samples to the reaction of Martian particulates with an anhydrous CO2 atmosphere activated by uv and ionizing radiations. The surface particles are ultimately altered by exposure to small but significant amounts of water at the sites. From the working model, we have predicted the peculiar nature of the chemical entities and demonstrated that the model is justified by laboratory data. The final confirmation of this model will entail a return to Mars, but the nature and implications of this chemistry for the Martian surface is predicted to reveal even more about Mars with further simulations in the laboratory.

A Search for Viable Organisms in a Lunar Sample

The hypothesis that the moon could harbor viable life forms was not verified on analysis of the first samnples from the Apollo 11 mission. Biological examnination of 50 grainis of the butlk fines confirmn the negative results obtained by the Manned Spacecraft Center quarantine teamyz. No viable life forms, including terrestrial contaminants, were found when the sample was tested in 300 separate environmtenits. Only colored illorganiic artifacts, resembling mnicrobial clonies, appeared aroun1cd some particles. Manned Spacecraft Center, Houston.

Corrections in the Pioneer Venus Sounder Probe Gas Chromatographic Analysis of the Lower Venus Atmosphere

Misidentification of two peaks from the Pioneer Venus sounder probe gas chromatograph (SPGC), also formerly known as the LGC, gave rise to quantitative errors in the abundances of oxygen, argon, and carbon monoxide. The argon abundance is estimated at 67 parts per million and that of carbon monoxide at 20 parts per million. At this time, no estimates for the oxygen abundance can be made.

Laboratory corroboration of the pioneer venus gas chromatograph analyses.

Laboratory simulation and tests of the inlet sampling system and columns of the Pioneer Venus gas chromatograph show that the sensitivity to argon is not diminished after the column regeneration step, argon isotopes are not separated, oxygen and sulfur dioxide are not produced in the inlet sampling system from sulfur trioxide, and sulfur trioxide is not formed from sulfur dioxide and oxygen. Comparisons of the volatile inventory of Venus and Earth imply similar efficiencies of early outgassing but a lower efficiency for later outgassing in the case of Venus. The high oxidation state of the Venus atmosphere in the region of cloud formation may prohibit the generation of elemental sulfur particles.

Carbon suboxide polymer, an explanation for the wave of darkening on Mars

The carbon suboxide thermal polymer or its irradiated product is affected by water vapor. The polymerized carbon suboxide simulates the Martian wave of darkening on an inner wall of a glass tube when humidified by passage of water vapor through the tube. The polymer is visibly darkened by the advancing vapor front. With increasing polymer thickness or water vapor concentration, or both, the wave of darkening similarly intensifies thus simulating the dark fringe in the Martian circumpolar areas. It is hypothesized that light and dark areas have polymer coatings, but light areas have small particles that scatter white light more effectively and appear brighter on the surface of Mars. It is proposed that on Mars, there is a continual lightening of the surface by particulate material settling from the atmosphere.