ALBERT

Description: The use of balloons/aerobots on Mars has been under consideration for many years. Concepts include deployment during entry into the atmosphere from a carrier spacecraft, deployment from a lander, use of super-pressurized systems for long duration flights, 'hot-air' systems, etc. Principal advantages include the ability to obtain high-resolution data of the surface because balloons provide a low-altitude platform which moves relatively slowly. Work conducted within the last few years has removed many of the technical difficulties encountered in deployment and operation of balloons/aerobots on Mars. The concept proposed here (a tethered balloon released from a lander) uses a relatively simple approach which would enable aspects of Martian balloons to be tested while providing useful and potentially unique science results. Tethered Micro-Balloons on Mars (TMBM) would be carried to Mars on board a future lander as a stand-alone experiment having a total mass of one to two kilograms. It would consist of a helium balloon of up to 50 cubic meters that is inflated after landing and initially tethered to the lander. Its primary instrumentation would be a camera that would be carried to an altitude of up to tens of meters above the surface. Imaging data would be transmitted to the lander for inclusion in the mission data stream. The tether would be released in stages allowing different resolutions and coverage. In addition during this staged release a lander camera system may observe the motion of the balloon at various heights above he lander. Under some scenarios upon completion of the primary phase of TMBM operations, the tether would be cut, allowing TMBM to drift away from the landing site, during which images would be taken along the ground.

Description: Mars aerobots constitute a class of mission nearly a factor of 10 smaller than earlier concepts for Mars balloons. A key goal is to achieve high payload mass fraction in a small total systems mass and to maximize the scientific potential of that payload. The "low and slow" attributes of aerobot flight paths afford advantages for many observations and measurements of Mars. Scientific objectives include surveys of remnant magnetism, studies of the surface with high resolution stereo imaging, and investigations of the structure and dynamics of the atmosphere with an in situ meteorology payload.

Description: Knowledge of the geology, style and time history of crustal processes on the icy Galilean satellites is necessary to understanding how these bodies formed and evolved. Data from the Galileo mission have provided a basis for detailed geologic and geo- physical analysis. Due to constrained downlink, Galileo Solid State Imaging (SSI) data consisted of global coverage at a -1 km/pixel ground sampling and representative, widely spaced regional maps at -200 m/pixel. These two data sets provide a general means to extrapolate units identified at higher resolution to lower resolution data. A sampling of key sites at much higher resolution (10s of m/pixel) allows evaluation of processes on local scales. We are currently producing the first global geological map of Europa using Galileo global and regional-scale data. This work is demonstrating the necessity and utility of planet-wide contiguous image coverage at global, regional, and local scales.

Description: Many field studies have been conducted that document the morphology of ventifacts and the directionality of their features relative to current and past wind regimes. Field plots and wind tunnel studies have identified heights and particle concentrations above the surface where maximum abrasion occurs. However, as of yet, the rates and detailed methods by which rocks abrade and evolve into ventifacts are poorly documented and understood. This abstract addresses this gap in knowledge by interpreting controlled laboratory and field analog studies. We begin with an overview of the methods by which the wind tunnel experiments and field studies were done, followed by how the resulting data were analyzed and interpreted. A presentation of the results comes next, after which the implications for rock abrasion and ventifact formation on Earth and Mars are discussed. We show that initial rock shape and texture play important roles in determining both rate and style of abrasion, with steep-sided, rough rocks eroding the fastest but with intermediate-angled faces exhibiting the greatest shape change. Most rocks tend to evolve toward an equilibrium shape whose form is poorly conducive to further abrasion. Most rocks on Mars and in terrestrial ventifact localities never reach this mature state, with erosion ceasing or slowing down due to exhaustion of the sand supply and other factors.

Description: Aeolian-produced rock textures found in the Mojave are compared to analogous features at the Pathfinder landing site.

Description: Galileo's SSI returned low resolution multispectral images at small phase angles which reveal terrain-and albedo-dependent spatial heterogeneities in Callisto's opposition effect.

Description: The results of high resolution imaging of the Martian surface by MOC, show that wind activity is a dominant process in the current environment, forming and modifying the surface from the equator to the poles.

Description: The IMP windsock experiment measured wind speeds at three heights within 1.2 m of the martian surface during Pathfinder landed operations. Data from the strongest breezes indicate aerodynamic roughness = 3 cm, wind friction speeds up to 1 m/sec.

Description: VEVA (Venus Exploration of Volcanoes and Atmosphere) is a potential Discovery mission.

Description: The Viking and the Mars Exploration Rover missions observed that the surface of Mars is encrusted by a thinly cemented layer tagged as "duricrust". A hypothesis to explain the formation of duricrust on Mars should address not only the potential mechanisms by which these materials become cemented, but also the textural and compositional components of cemented Martian soils. Elemental analyzes at five sites on Mars show that these soils have sulfur content of up to 4%, and chlorine content of up to 1%. This is consistent with the presence of sulfates and halides as mineral cements. . For comparison, the rock "Adirondack" at the MER site, after the exterior layer was removed, had nearly five times lower sulfur and chlorine content , and the Martian meteorites have ten times lower sulfur and chlorine content, showing that the soil is highly enriched in the saltforming elements compared with rock.Here we propose two alternative models to account for the origin of these crusts, each requiring the action of transient liquid water films to mediate adhesion and cementation of grains. Two alternative versions of the transient water hypothesis are offered, a top down hypothesis that emphasizes the surface deposition of frost, melting and downward migration of liquid water and a bottom up alternative that proposes the presence of interstitial ice/brine, with the upward capillary migration of liquid water.