Geophysical Exploration of Vesta

Dawn’s year-long stay at Vesta allows comprehensive mapping of the shape, topography, geology, mineralogy, elemental abundances, and gravity field using it’s three instruments and highprecision spacecraft navigation. In the current Low Altitude Mapping Orbit (LAMO), tracking data is being acquired to develop a gravity field expected to be accurate to degree and order ~20 [1, 2]. Multi-angle imaging in the Survey and High Altitude Mapping Orbit (HAMO) has provided adequate stereo coverage to develop a shape model accurate to ~10 m at 100 m horizontal spatial resolution. Accurate mass determination combined with the shape yields a more precise value of bulk density, albeit with some uncertainty resulting from the unmeasured seasonally-dark north polar region. The shape and gravity of Vesta can be used to infer the interior density structure and investigate the nature of the crust, informing models for Vesta’s formation and evolution

Geomorphological Analysis of Mass Balances of Martian Valley Networks in Western Terra Sirenum

In recent years, there has been a great deal of interest in Martian valley networks. Especially when [1] and how and among witch circumstances they have been formed [2] has been discussed up to now. On the whole, at what time Martian valley networks have been generated and that water might has been the forming agent is pretty certain now. A substantial amount of research by a lot of studies is published about that issue. However, a central question that needs to be addressed in this context is, how much water was required to create valley networks on early Mars. The intention of this study focuses on a geologic and geomorphological analysis of valley networks in the Western part of Terra Sirenum presenting calculations of discharge, transportation and erosion rates to improve the insight in a time there must have been other environmental and climate conditions, whose processes are still not sufficiently explored and understood

Lunar volcanic feature catalog for Dawn

Except for a number of low-resolution full-globe images obtained by the Hubble Space Telescope the surface of Vesta remains largely unknown. New image data from NASA’s Dawn mission that will arrive at asteroid Vesta in July 2011 for a 9 month systematic mapping phase to investigate Vesta’s geology [1]. This proposal of lunar analogues relies on medium to lowresolution image data from the Clementine and Lunar Orbiter missions as well as high-resolution image data obtained from the Lunar Reconnaissance Orbiter (LRO), Chandrayaan-1 and Kaguya camera experiments that are comparable to the expected Dawn instrument resolutions

Compositional mapping of Vesta quadrangle V22

The Dawn spacecraft [1] is orbiting and mapping 4 Vesta since July 2011 by using the Framing Camera (FC) and the Visible and InfraRed Imaging spectrometer (VIR) [3]. VIR acquired hyper-spectral images of Vesta’s surface in the wavelength range from 0.25 to 5.1μm during Approach, Survey and High Altitude Mapping (HAMO) orbits that pro-vided very good coverage of the surface (>65% of the complete surface). The VIR nominal pixel resolution ranges from 1.3 km (Approach phase) to 0.18-0.15 km (HAMO). The coverage allowed a near global study of Vesta’s surface mineralogy and the development of a series of four quadrangle maps [4]. Here we present the results of the spectroscopic analysis achieved for the quadrangle V22, which covers Vesta’s surface between 57°N-57°S and 0°-180°

Geologic Mapping of the AV-5 Floronia quadrangle of asteroid 4 Vesta

NASA’s Dawn spacecraft entered orbit of the inner main belt asteroid 4 Vesta on July 16, 2011, and is spending one year in orbit to characterize the geology, chemical and mineralogical composition, topography, shape, and internal structure of Vesta before departing to asteroid 1 Ceres in late 2012. As part of the Dawn data analysis the Science Team is conducting geological mapping of the surface, in the form of 15 quadrangle maps. This abstract reports results from the mapping of quadrangle Av-5, named Floronia

Exploring the smallest terrestrial planet: Dawn at Vesta

The Dawn mission is designed to map Vesta and Ceres from polar orbit for close to one year each. The ion-propelled Dawn spacecraft is illustrated in Figure 1. Dawn carries a framing camera with clear and color filters, a visible and infrared mapping spectrometer, a gamma ray and neutron spectrometer, and obtains radiometric data on the gravity field. The camera obtains stereo imagery from which a global shape and topography model are derived. The mapping spectrometer determines the mineral composition of the surface and the gamma and neutron spectrometer determines the elemental composition. As Dawn approaches Vesta, as illustrated in Figure 2, it measures the rotational characteristics of the body to determine the orientation of the rotation axis. This in turn determines when solar illumination reaches the north pole and when mapping can be completed. As shown in Figure 3, there are three science orbits: Survey at a radial distance of 3000 km and a period of 69 hr; high-altitude mapping at a radial distance of 950 km and a period of 12.3 hr; and low-altitude mapping at a radius of 465 km and a period of 4 hours. Vesta is the ultimate source of the HED meteorites from which much has been learned about their parent body. By the time of this presentation we will have surveyed the region around Vesta for moons, determined a much more accurate mass and rotation axis for Vesta, and have preliminary information on surface features and composition from the survey orbit