Applied to Mars Research and Exploration

Geologists explore the Earth at specific surface locations and then integrate these data using more synoptic approaches. Planetary geoscientists, however, are forced by the nature of the available data to start from synoptic and orbital data and work down toward the surface. We describe Advanced Visualization in Solar System Exploration and Research (ADVISER), a problem-solving environment that uses advanced visualization techniques to bridge an important gap between the cartographic data sets derived by remote sensing and their application in geoscientific research. ADVISER integrates and extends state-of-the-art hardware and software technologies into a set of tools that provide the planetary geoscientist with the capability to operate and analyze data and to undertake mapping as if they were on or near the surface of a planet. Application of these tools (e.g., virtual field tools and notebook) to analysis of the north polar-layered terrain on Mars provides insight into polar cap formation and evolution and mission planning activities. Introduction and Background Geologists explore the Earth primarily through fieldwork and analysis of the geological record at various points on the surface. They then integrate these individual points of understanding through more synoptic analyses often aided by the integrating perspectives seen from image and topographic data acquired from aircraft and Earth orbit. Planetary geoscientists commonly work toward an understanding in the reverse order. The distances and times involved dictate that the first data from individual moons and planets comes from flybys and orbital spacecraft, perhaps in some cases evolving toward the deployment of a few landers and rovers, and for the Moon, human explorers. Now that global data sets are available for the Moon, Mars, and Venus, we can begin to undertake the detailed exploration of planetary surfaces that is required for the full understanding of the evolution of planets (e.g., Head, 2001). How do we accomplish this? In only a very few cases can we expend the resources to put a lander and rover, and thus our eyes and ears, down onto the surfaces of the ADVISER: Immersive Scientific Visualization Applied to Mars Research and Exploration James W. Head, III, Andries van Dam, Samuel G. Fulcomer, Andrew Forsberg, Prabhat, Graham Rosser, and Sarah Milkovich planets. The successful Pathfinder rover (e.g., Golombek et al., 1999) and the currently operating Mars Exploration Rovers (e.g., Squyres et al., 2004a, 2004b) are testimony to the exciting results that can be obtained by such surface exploration. Fortunately, developments in advanced visualization and immersive virtual reality environments have created the ability to place the geoscientist back down on and near the surface to visit virtually any part of the planet they wish to see, and to regain the perspective that is the foundation for the understanding of the geological relationships necessary to unlock the record of the history of the planets. Specifically, we are using a Cave Automatic Virtual Environment (CAVE) fully immersive virtual reality system (Cruz et al., 1993) to put geoscientists in remote places such as Mars. Our CAVE’s construction physically consists of four 8-foot square display surfaces that have edges seamlessly joined to form a cube-like volume. We have a front wall, a left wall, a right wall, and a floor surface (Figure 1). Computer-generated stereo images are projected by one computer per wall using an Electrohome 9500 projector. Our four-node cluster has one nVidia Quadro FX 3000G graphics card per computing machine. All of these components are synchronized to present to one or more viewers a virtual environment of Mars that is generated from various data sources (e.g., topography and remote sensing data). Image and altimetry data, as well as associated data sets describing the physical and mineralogical properties of the surface materials, are now available for Mars (and, to a lesser extent, for other planetary bodies), and a substantial amount of effort has been invested in putting these data sets in map form and placing them in a common cartographic coordinate system, an essential step before they can be used comparatively. Aspects of this process of photogrammetric/cartographic analysis of Mars remote sensing data are described in several other papers in this special issue of PE & RS. Even with the key data sets available in common cartographic coordinates, however, extracting the maximum geoscientific insight from them is a challenging task that depends critically on having the right software tools. What is required to overcome this major barrier to the exploitation of planetary photogrammetry and remote sensing data? Clearly, a set of tools that can both ingest data sets from multiple missions and present them to the user in the most effective way are required. Unfortunately, much of the planetary science community is not aware of the computer science and technology developments that can enable PHOTOGRAMMETRIC ENGINEER ING & REMOTE SENS ING Oc t obe r 2005 1219 James W. Head, III and Sarah Milkovich are with the Department of Geological Sciences, Brown University, Providence, RI 02912 (James_Head_III@brown.edu). Andries van Dam, Andrew Forsberg, and Graham Rosser are with the Department of Computer Science, Brown University, Providence, RI 02912. Samuel G. Fulcomer and Prabhat are with the Center for Computing and Visualization, Brown University, Providence, RI 02912. Photogrammetric Engineering & Remote Sensing Vol. 71, No. 10, October 2005, pp. 1219–1225. 0099-1112/05/7110–1219/$3.00/0 © 2005 American Society for Photogrammetry and Remote Sensing MARS-P2.qxd 9/9/05 8:34 PM Page 1219