The WISDOM Radar: Unveiling the Subsurface Beneath the ExoMars Rover and Identifying the Best Locations for Drilling

The search for evidence of past or present life on Mars is the principal objective of the 2020 ESA-Roscosmos ExoMars Rover mission. If such evidence is to be found anywhere, it will most likely be in the subsurface, where organic molecules are shielded from the destructive effects of ionizing radiation and atmospheric oxidants. For this reason, the ExoMars Rover mission has been optimized to investigate the subsurface to identify, understand, and sample those locations where conditions for the preservation of evidence of past life are most likely to be found. The Water Ice Subsurface Deposit Observation on Mars (WISDOM) ground-penetrating radar has been designed to provide information about the nature of the shallow subsurface over depth ranging from 3 to 10 m (with a vertical resolution of up to 3 cm), depending on the dielectric properties of the regolith. This depth range is critical to understanding the geologic evolution stratigraphy and distribution and state of subsurface H2O, which provide important clues in the search for life and the identification of optimal drilling sites for investigation and sampling by the Rover's 2-m drill. WISDOM will help ensure the safety and success of drilling operations by identification of potential hazards that might interfere with retrieval of subsurface samples

ORIGIN OF THE CHAOTIC MOTION OF THE SATURNIAN SATELLITE ATLAS

“The final publication is available at http://iopscience.iop.org/article/10.3847/0004-6256/151/5/122/meta

Factors affecting survival in Mediterranean populations of the Eurasian eagle owl

The survival rate is a key parameter for population management and the monitoring of populations. Thus, an analysis of survival rate variations and the factors influencing the same is essential for understanding population dynamics. Here, we study the factors determining the survival and the causes of mortality of the Eurasian eagle owl (Bubo bubo) in two Spanish Mediterranean populations (Murcia and Seville) where the species has a high population density and breeding success; yet its survival rates and the factors that affect them are unknown. Between 2003 and 2010, 63 breeding owls were captured and radio-tracked. Three monthly (quarterly) survival rates were estimated using known-fate models in the program MARK. The mean overall annual survival rate was 0.776 (95 % CI: 0.677, 0.875). We observed survival differences between sexes, and between the breeding and non-breeding periods, although no overwhelming support was found for any particular model. We concluded that (i) females have a lower survival rate than males, probably due to their larger home ranges, which increase the risk of mortality; (ii) the survival rates of both sexes were lower during the non-breeding period; and (iii) the causes of mortality differed significantly between the two populations, gunshot being the main cause in Seville and electrocution in Murcia.Peer Reviewe

Performances of the WISDOM GPR Designed for the Shallow Sounding of Mars

WISDOM (Water Ice and Subsur-face Deposit Observations on Mars) is a Ground Pene-trating Radar (GPR) that is one of the panoramic in-struments selected to be part of the Pasteur payload onboard the Rover of the ExoMars mission. These Pas-teur Panoramic Instruments (the wide angle camera PANCAM, the infrared spectrometer MIMA and WISDOM) will perform large-scale scientific investi-gations at the sites the Rover will visit. Among these instruments, WISDOM is the only one that can provide information about the subsurface structure prior to drilling. WISDOM has been designed to characterize the shallow subsurface structure of Mars. It will give access to the geological structure, electromagnetic na-ture, and, possi-bly, to the hydrological state of the shallow subsurface by retrieving the layering and prop-erties of the buried reflectors. In addition, the data it will provide will be used to determine the most promis-ing locations at which to obtain underground samples with the drilling system mounted on board the rover. This paper describes the WISDOM instrument particular attention is paid on its antennas design as well as on its operations during the mission. Eventually the first measurements performed with a WISDOM prototype on Earth are presented. They show very promising results to well below 2-meter depth