The Advanced Communications Technology Satellite (ACTS) has been a main focus of NASA's program to provide high-speed telecommunications resources to researchers, business and industry. The satellite was launched by the STS-51 Space Shuttle Discovery crew on September 12, 1993. The ACTS is the first all-digital, gigabit-capacity communication satellite. Operating in the K- and Ka-frequency bands (20 GHz and 30 GHz, respectively), ACTS is pioneering dynamic hopping spot beams and advanced on-board traffic switching and processing. Located in geosynchronous orbit at 100 degrees west longitude, ACTS is the first satellite with the ability to carry digital communications at standard fiber-optic data rates (622 MBS) with the same quality of transmission, and also offers added performance and cost advantages. ACTS technology integrates satellite and existing ground fiber-optic systems for transmission of data at high rates of speed over great distances and to the most remote locations.
NASA joined with ARPA (the Advanced Research Projects Agency) to fund experiments using the ACTS satellite and ground stations. ACCAD was funded for participation in one of these experiments, and was part of a team funded for another.
The first experiment integrated two large scale simulation models running on supercomputers in two locations. These models passed boundary conditions,other parameters and visual images using the ACTS satellite. Model A used atmospheric conditions as input to simulate changing conditions in the Great Lakes. Model B used ground (water) conditions to simulate atmospheric phenomena over the Lakes. By exchanging these conditions in a dynamic fashion, the models worked together to provide forecasts of changing weather patterns over the region. ACCAD provided high data rate communications expertise, supercomputer programming, and scientific visualization capabilities to generate graphic images and computer animations which were simultaneously broadcasted over the satellite to all locations involved in the experiment. PI: Wayne Carlson, Keith Bedford and Allison Brown.
The second experiment was designed to use the satellite for medical triage and remote radiation treatment planning.The primary aim of radiation therapy is to deliver a tumorcidal dose of radiation to a tumor volume while minimizing doses to surrounding, normal tissues. Dose calculations were performed and superimposed on 3D visualizations of the anatomy constructed at ACCAD. The system developed by the research team at ACCAD, the Ohio Supercomputer Center, the University of Hawaii and Georgetown University consisted of medical imaging devices, volumetric image models, 3D image processing and visualization workstations, and supercomputers. Medical imaging data were transmitted by the satellite to a central processing computer at ACCAD. Reconstructive modeling and predictive computations were carried out by the supercomputers and were distributed to the operating sites at Hawaii and Georgetown by the ACTS satellite. Visualization of volumetric data took place on the workstations using visualization software developed at ACCAD. A radiology team at Georgetown was able to interactively manipulate the rendering of the visualization by changing parameters determining viewing, shading, lighting, etc. In addition, the interface provided the capability for steering segmentation which was remotely computed on the supercomputer. The result of the interaction was a treatment plan sent by the satellite to the medical team in Hawaii.
PI: Wayne Carlson, Suen Moon, David Y.Y. Yun, Hong-Mei Chen