Radar Exploration of Mars: Recent Results and Progresses - Planetary Exploration and Science: Recent Results and Advances - page 74

Chapter 5
Radar Exploration of Mars: Recent Results
and Progresses
Stefano Giuppi
Abstract Radar is the acronym for RAdio Detection And Ranging. It is an
object-detection system, which principles consist basically in the transmission,
propagation, and reflection of radio waves. After the first exploitations in the mili-
tary field, radar evolved as a useful device also in the civil field, widely extending
its applications. After having been tested on Earth, radar capabilities to penetrate a
planet surface have been applied on Mars exploration. MARSIS, part of the payload
of ESA Mars Express mission, and SHARAD, embarked on board NASA MRO
spacecraft, are two nadir-looking radar sounders which use synthetic aperture radar
(SAR) techniques. The two instruments are complementary: MARSIS is able to
detect subsurface interfaces at great depth, while SHARAD can better discriminate
subsurface interfaces close to the surface. The two radars achieved information
on Martian craters, both exposed and buried, provided geophysical evidences for
the former existence of an ocean in the Martian northern hemisphere, investigated
Martian pedestal craters, provided a useful contribution to analyze the nature of the
Medusae Fossae Formation, and probed the ice-rich polar layered deposits of Mars,
detected a boundary in many areas of plains off the south polar layered deposits.
The analysis of MARSIS data enables to study also the Martian ionosphere and to
estimate its TEC producing the related maps. Through volumetric (3D) study, the
two radars provide an opportunity to extend our knowledge of a planetary body
to the third dimension, allowing to detect features that are difficult to investigate
in vertical profiles. Since Martian polar terrains are considered a close analogue
to the material forming the crusts of Jovian satellites Europa and Ganymede, a
radar sounder, RIME, has been selected as part of ESA's first large-class mission
in Cosmic Vision Program, JUICE, the first orbiter on an icy moon which will
investigate the emergence of habitable worlds around gas giants, characterizing
Ganymede, Europa, and Callisto as planetary objects and potential habitats.
Keywords Radar ￿ Mars ￿ Subsurface interfaces ￿ MARSIS ￿ SHARAD