R. Bianchi

Self‐affine behavior of Martian topography at kilometer scale from Mars Orbiter Laser Altimeter data

[1]xa0We used Mars Orbiter Laser Altimeter (MOLA) data from the current Mars Global Surveyor mission to characterize the topographic roughness of the Martian surface and to provide a mean to evaluate clutter at long (10–300 m) wavelengths. Such wavelengths are relevant for the MARSIS and SHARAD subsurface radars, which will be flown in future missions to Mars. The method of analysis is based on the assumption that topography can be described as a self-affine fractal: 30-km-long segments of MOLA altimetry profiles have thus been reduced to the topographic parameters RMS height, RMS slope, and Hurst exponent, this last related to the fractal dimension, which can be used as inputs to a near-nadir radar scattering model. The values of the Hurst exponent are greater than 0.5 for most of the surface, meaning a scaling behavior which is almost self-similar. Maps of RMS height and Hurst exponent show that these two parameters have very different spatial distributions: whereas the RMS height is patterned after the north-south dichotomy, the Hurst exponent follows a latitudinal trend. We make use of a multivariate method called G-mode to classify profiles in the three-dimensional parameter space: we find several roughness units, some of which have a strong correlation with certain geologic units, while others are bound by latitude. However, at scales between 300 m and 3 km, large stretches of the surface of Mars share common statistical properties of topography, independent from the north-south dichotomy.

MA_MISS: Mars multispectral imager for subsurface studies

Abstract The Italian drill “DEEDRI” is going to be the lander based sample acquisition system for the Mars Surveyor Program of the Mars Sample Return mission. DEEDRI is capable to collect core/sand sample of the martian soil down to 50 cm in depth. The MA_MISS experiment belongs to the DEEDRI system and it will be dedicated to observe the wall of the excavated hole in terms of infrared spectral reflectance in the range 0.8–2.8 μm. The spectral sampling is about 20 nm while the spatial sampling is 100 μm over the target. The optical window of MA_MISS is placed very close to the drill tip so that the target view to be observed can span from the soil down to 50 cm. The proximity optics and electronics of MA_MISS have to be very miniaturized since they will be collocated inside the drill tool in a very limited volume of about 25 mm in diameter. On the other side the main electronics will be on the lander and it will communicate through an interface based on slip rings devices. MA_MISS can acquire in different observation modes. The images are scanned by moving the DEEDRI itself. One image ring is built up by acquiring contiguous images of the MA_MISS slit. The study of the Martian subsurface will provide important constraints on the nature, timing and duration of alteration and sedimentation processes on Mars, as well as on the complex interactions between the surface and the atmosphere. This study will permit to infer the history of erosion, transport and deposition of loose material. Alteration processes can dominate the mineralogy of the Martian surface: it will be essential to study the mineralogy of deeper layers, where a more limited alteration took place. MA_MISS can provide very important scientific return from the subsurface of Mars along with a selection criteria for the samples collection.

MARS-IRMA: in-situ infrared microscope analysis of Martian soil and rock samples.

IRMA (the acronym stands for InfraRed Microscope Analysis) is a hyperspectral imaging spectrometer which is capable, in its present design, to achieve a spatial resolution of 38 μm in the 0.8–5 μm infrared spectral range. IRMA has the goal to first ever quantitatively characterize the mineralogy and the microphysical structure of the materials of the Martian soils and rocks down to the depth available to a lander sampling mechanism. The experiment has been selected by the Italian Space Agency (ASI), in the framework of the Italian participation to the NASAs Mars Surveyor Programme, to be part of the Italian Package for Scientific Experiments (IPSE). IPSE was to fly on-board the ill-fated MARS2003 MARS SAMPLE RETURN Mission, postponed during the early months of 2000 to a later date (possibly 2007). IRMA present state of development is compatible with a flight readiness in 2007. n nIPSE is a small laboratory devoted to the analysis of in situ collected samples of rock and soil of Martian material. Details on IPSE are given in a paper in this same journal issue. n nIRMA will provide detailed information on: n• ntexture, habit and microphysical properties of the grains and particulates of the Martian soil as well as the petrography of Martian rocks, with a spatial resolution of the order of the tens of micron. n n• nMineralogical composition and relative mineral abundances of the rocks and soils, with a relative accuracy of the order of 1%. A Signal to Noise Ratio of at least 100 shall be required to achieve this goal n n n n nIRMA measurements shall provide essential contributions to the understanding of outstanding scientific issues such as the history of water and other volatiles, e.g., CO2, the role of physical and chemical weathering in the past and present day Mars and hence the assessment of the environmental conditions present on the martian surface throughout its history.

The international package for scientific experiments (IPSE) for Mars surveyor program

Abstract IPSE is a micro-laboratory for Mars soil and environment analysis. It provides the capability to serve and handle scientific miniaturised instruments accommodated inside its envelope. The instruments have the goal to perform in situ study of the collected martian samples, thus quantitatively characterizing the mineralogy, the composition, the microphysical structure of the materials of the Martian soils down to the depth available to the sampling mechanism. Given the complex structure of the surface material it will be essential to perform in-situ science, both at the surface and at different depths. This is done in order to validate remote sensing observations through specific measurements, identify local characteristics of the selected landing areas, document sample collection both for in situ and sample return. IPSE is an example of a small and flexible lab, that can be integrated on different Landers and Megarovers. IPSE contains: • Scientific instruments • A small robotic arm - with five degrees of freedom - to provide samples to the IPSE instruments. • Power conditioning. • Electronics for system and thermal control, communications and instrument data handling. The Phase A report for all the IPSE instruments has been already provided to the Italian Space Agency. The experiments MAGO, IRMA, MA_FLUX are inherited from previous space qualified instruments and breadboards of them already exist. DOSE is a new experiment, however, a breadboard of the detector and of the photomultiplier is under development.

IPSE: Italian package for scientific experiments

IPSE is a scientific autonomous micro-laboratory for Mars soil and environment analysis. It is designed to provide the capability to serve, handle and manage scientific miniaturised instruments accommodated inside its envelope. These instruments will carry out measurements on soil samples, atmosphere, radiation environment and dust flux. IPSE is an example of a small and flexible laboratory, that can be integrated on different landers and rovers. It contains: scientific instruments; a small robotic arm to provide samples to the instruments; power conditioning; electronics for system and thermal control, communications and instrument data handling.