Published in Planetary and space science
This report summarizes observations of returned Apollo rocks and soils, lunar surface images, orbital observations, and experimental impacts related to the erosion and comminution of rocks exposed at the lunar surface. The objective is to develop rigorous criteria for the recognition of impact processes that assist in distinguishing "impact" from o...
Published in Planetary and Space Science
• In-situ measurements of heat plume and ionization by a radioisotope generator. • Atmospheric electrical conductivity is enhanced by ~100x near generator. • Effects on Mars or Titan lander measurements are discussed. • Titan conductivity enhancement is significant but very localized.
Published in Planetary and Space Science
Highlights•Collisions are treated on the basis of recent total and differential cross sections.•Dissociative recombination of O2+ and CO2+ appear equally important for O escape.•Little variation of hot oxygen exosphere density with solar activity.•Loss of C due to photodissociation of CO higher than in previous calculations.•Ratio of O and C loss d...
Published in Planetary and Space Science
Catastrophic floods of enormous proportions are thought to have played a major role in the excavation of some of the Solar System s largest channels; the circum-Chryse outflow channels. The generation of the floods has been attributed to both the evacuation of regional highland aquifers and ancient paleo-lakes. Numerous investigators indicate that ...
Published in Planetary and Space Science
The “ponds” on asteroid (433) Eros are fine-grained deposits approximating flat (quasi-equipotential) surfaces with respect to local topographic depressions (eg, craters) in spacecraft images. These ponds are discussed in the context of laboratory simulation experiments, crater-related ponded and pitted deposits observed on Mars and Vesta, terrestr...
Published in Planetary and Space Science
Remote sensing observations meet some limitations when used to study the bulk atmospheric composition of the giant planets of our solar system. A remarkable example of the superiority of in situ probe measurements is illustrated by the exploration of Jupiter, where key measurements such as the determination of the noble gases׳ abundances and the pr...
Published in Planetary and Space Science
Highlights•We estimate the abundance of very large grains (with radii >1μm) in the Galaxy.•The central hypothesis is that dense molecular cloud cores are the sites of the formation of very large grains.•Very large grains are responsible for 2–9 percent of the total dust mass in the Galaxy.•The derived abundance of very large grains is so small that...
Published in Planetary and Space Science
•A miniature laser–ablation mass spectrometer (LMS) is presented.•The elemental composition of a sample of Allende meteorite is measured with LMS.•LMS features robustness, precision and high sensitivity, high spatial resolution and small sample consumption.•The performance of LMS as an instrument for in situ planetary exploration is demonstrated.
Published in Planetary and Space Science
•We present evidence to conclude that it is very probable that comet C/2012 S1 (ISON) will disintegrate before reaching perihelion. Some Oort Cloud comets exhibit a signature (a slope discontinuity event (SDE)+a dip after the event) that has a predictive power.•Figs. 1 and 7 of this work are particularly revealing. The comet is following the path o...
Published in Planetary and Space Science
Highlights•The agreement between the timing and model-shock normals is Alfven mach number dependent.•The bow shock motion is predominantly in the Sun–Earth direction.•Gaussian shock velocity distribution is found for shock speeds less than ~80km/s.•High-speed shock motion is found to be strongly related to propagating discontinuities in the solar w...
