Orbital Periodicities Reflected in Ancient Surfaces of our Solar System and the Implications for a Record of Early Life

Uniformitarian processes, governed by invariant physical laws, remain the most reliable source for reconstructing the past. Driving many of the repetitive, predictable processes are the orbital dynamics of the Sun-Planet-Moon systems. Astronomical periodicities range from a few hours (tides) to thousands of years (Milankovitch). These periodicities, combined with geomorphic observations of planetary surfaces, constrain the time-dependent processes and allow for reconstruction of events and conditions favorable for sedimentary accumulations. This research suggests that seasonal sedimentary processes are dominant on Titan and Mars, and have played a significant role in the formation of ancient banded-iron formations (BIF\u27s) on Earth. Earth, Mars, and Titan, the planetary bodies in our solar system with a history of flowing liquids, are characterized here to preserve seasonal and longer-period orbital signatures in layered strata. Surface features also suggest that volatile transient liquids, subject to solid phase sequestering, are dependent not only on climate forcing, but additionally on unique physiographic features of the planetary body. Climate change is subject to longer period orbital oscillations such as precession, eccentricity, and obliquity, and to the rise in or loss of surface liquids (oceans and seas) and atmospheres. Thickness and mineralogy time-series profiles from the Dales Gorge Member of the Brockman Iron Formation suggest cycles and periodicities similar to modern current velocity profiles. First-order sinusoidal series patterns are interpreted as seasonal changes in bidirectional movement of ocean floor sediment, displaying second-order tidal influence. Sedimentary accumulations consist of iron-dominate organic sequences linked to slower current movement alternating with silica-dominate sequences indicative of modestly higher energy currents. Directional current oscillations may also contribute to changing mineralogy. Titan and Martian\u27s surfaces also demonstrate active seasonal processes. Rivers within Titan\u27s northern polar region carry sediments from the more distal highland, through rugged foothills, to the lowland basins. Headward erosion during dynamic hydrocarbon seasonal rains carves the present valley and ridge systems on the flanks of the highlands. This research predicts that layered seasonal sedimentary varves have accumulated in the large endhoreic basin in the northern polar region of Titan

NASA/ESA CV-990 Spacelab Simulation (ASSESS 2)

To test the validity of the ARC approach to Spacelab, several missions simulating aspects of Spacelab operations have been conducted as part of the ASSESS Program. Each mission was designed to evaluate potential Shuttle/Spacelab concepts in increasing detail. For this mission, emphasis was placed on development and exercise of management techniques planned for Spacelab using management participants from NASA and ESA who have responsibilities for Spacelab 1 which will be launched in 1980

Electron Paramagnetic Resonance in Biology

A review of the theories of electron paramagnetic resonance in biology is presented, including a discussion of the nature of the physical observation, followed by examples of materials of biological interest. Iq discussing these examples, information is presented in terms of the nature of the starting material under observation rather than the nature of the magnetic entities observed. The examples proceed from the simpler molecules of biological interest (metabolites, vitamins, cofactors) into the more complex materials (polymers, proteins, nucleic acids) toward cellular organelles (mitochondria, chloroplasts) and, finally, to whole cells, organisms and organs. The observation of photoinduced unpaired electrons in photosynthetic material is described and the various parameters controlling it are discussed. The basic observation is interpreted in terms of a primary photophysical act of quantum conversion