Fine Particles on Mars: Observations with the Viking 1 Lander Cameras

Towards Camera-LIDAR Fusion-Based Terrain Modelling for Planetary Surfaces: Review and Analysis

In recent decades, terrain modelling and reconstruction techniques have increased research interest in precise short and long distance autonomous navigation, localisation and mapping within field robotics. One of the most challenging applications is in relation to autonomous planetary exploration using mobile robots. Rovers deployed to explore extraterrestrial surfaces are required to perceive and model the environment with little or no intervention from the ground station. Up to date, stereopsis represents the state-of-the art method and can achieve short-distance planetary surface modelling. However, future space missions will require scene reconstruction at greater distance, fidelity and feature complexity, potentially using other sensors like Light Detection And Ranging (LIDAR). LIDAR has been extensively exploited for target detection, identification, and depth estimation in terrestrial robotics, but is still under development to become a viable technology for space robotics. This paper will first review current methods for scene reconstruction and terrain modelling using cameras in planetary robotics and LIDARs in terrestrial robotics; then we will propose camera-LIDAR fusion as a feasible technique to overcome the limitations of either of these individual sensors for planetary exploration. A comprehensive analysis will be presented to demonstrate the advantages of camera-LIDAR fusion in terms of range, fidelity, accuracy and computation.

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 Experiment's 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.

Results from the Mars Pathfinder camera

Images of the martian surface returned by the Imager for Mars Pathfinder (IMP) show a complex surface of ridges and troughs covered by rocks that have been transported and modified by fluvial, aeolian, and impact processes. Analysis of the spectral signatures in the scene (at 440- to 1000-nanometer wavelength) reveal three types of rock and four classes of soil. Upward-looking IMP images of the predawn sky show thin, bluish clouds that probably represent water ice forming on local atmospheric haze (opacity approximately 0.5). Haze particles are about 1 micrometer in radius and the water vapor column abundance is about 10 precipitable micrometers.

One Mars Year: Viking Lander Imaging Observations

Throughout the complete Mars year during which they have been on the planet, the imaging systems aboard the two Viking landers have documented a variety of surface changes. Surface condensates, consisting of both solid H(2)O and CO(2), formed at the Viking 2 lander site during the winter. Additional observations suggest that surface erosion rates due to dust redistribution may be substantially less than those predicted on the basis of pre-Viking observations. The Viking 1 lander will continue to acquire and transmit a predetermined sequence of imaging and meteorology data as long as it is operative.

Mineralogic and Petrologic Implications of Viking Geochemical Results From Mars: Interim Report

Chemical results from four samples of martian fines delivered to Viking landers 1 and 2 are remarkably similar in that they all have high iron; moderate magnesium, calcium, and sulfur; low aluminum; and apparently very low alkalies and trace elements. This composition is best interpreted as representing the weathering products of mafic igneous rocks. A mineralogic model, derived from computer mixing studies and laboratory analog preparations, suggests that Mars fines could be an intimate mixture of about 80 percent iron-rich clay, about 10 percent magnesium sulfate (kieserite?), about 5 percent carbonate (calcite), and about 5 percent iron oxides (hematite, magnetite, maghemite, goethite?). The mafic nature of the present fines (distributed globally) and their probable source rocks seems to preclude large-scale planetary differentiation of a terrestrial nature.

Scientific Results of the Viking Missions

The two Viking missions to Mars have been extraordinarily successful. Thirteen scientific investigations yielded information about the atmosphere and surface. Two orbiters and landers operating for several months photographed the surface extensively from 1500 kilometers and directly on the surface. Measurements were made of the atmospheric composition, the surface elemental abundance, the atmospheric water vapor, temperature of the surface, and meteorological conditions; direct tests were made for organic material and living organisms. The question of life on Mars remains unanswered. The Viking spacecraft are designed to continue the investigations for at least one Mars year.

The Surface of Mars: The View from the Viking 2 Lander

Viking 2 lander began imaging the surface of Mars at Utopia Planitia on 3 September 1976. The surface is a boulder-strewn reddish desert cut by troughs that probably form a polygonal network. A plateau can be seen to the east of the spacecraft, which for the most probable lander location is approximately the direction of a tongue of ejecta from the crater Mie. Boulders at the lander 2 site are generally more vesicular than those near lander i. Fines at both lander sites appear to be very fine-grained and to be bound in a duricrust. The pinkish color of the sky, similar to that observed at the lander I site, indicates suspension of surface material. However, the atmospheric optical depth is less than that at the lander I site. After dissipation of a cloud of dust stirred during landing, no changes other than those stemming from sampling activities have been detected in the landscape. No signs of large organisms are apparent at either landing site.

Search for Organic and Volatile Inorganic Compounds in Two Surface Samples from the Chryse Planitia Region of Mars

Two surface samples collected from the Chryse Planitia region of Mars were heated to temperatures up to 500 degrees C, and the volatiles that they evolved were analyzed with a gas chromatograph-mass spectrometer. Only water and carbon dioxide were detected. This implies that organic compounds have not accumulated to the extent that individual components could be detected at levels of a few parts in 10(9) by weight in our samples. Proposed mechanisms for the accumulation and destruction of organic compounds are discussed in the light of this limit.

Viking Magnetic Properties Investigation: Preliminary Results

Three permanent magnet arrays are aboard the Viking lander. By sol 35, one array, fixed on a photometric reference test chart on top of the lander, has clearly attracted magnetic particles from airborne dust; two other magnet arrays, one strong and one weak, incorporated in the backhoe of the surface sampler, have both extracted considerable magnetic mineral from the surface as a result of nine insertions associated with sample acquisition. The loose martian surface material around the landing site is judged to contain 3 to 7 percent highly magnetic mineral which, pending spectrophotometric study, is thought to be mainly magnetite.