The goal of the Center for Simulation of Advanced Rockets is comprehensive simulation of solid-propellant rockets. Achieving this goal will require advancements in technical issues related to several scient@ disciplines, in system integration, and in the computational infrastructure for supporting such large-scale simulations.he ability to launch a payload into orbit or to escape Earth's gravity entirely, although only about 40 years old, is almost taken for granted. Hundreds of devices in Earth orbit provide global communications, entertainment, and a vast array of scientific data about Earth and the universe beyond. The US Space Shuttle represents the zenith of this activity, with a 4.5-million-pound vehicle and a crew of seven blasted into orbit routinely on a near-monthly schedule.Solid-propellant rockets perform the heavy lifting in the aerospace industry, providing the immense thrust required to launch large payloads into Earth orbit or into outer space. In the solid booster stage's brief but fiery lifetime-typically only one to two minutes-it pushes the payload the first 30 miles or so above the Earth, where a more easily controlled liquid-fuel rocket takes over for the final nudge into orbit or beyond.The tremendous complexity of rocket systems has received almost universal, if tacit, recognition. Everyone has heard, "This isn't rocket science" or "It doesn't take a rocket scientist to figure that out," in reference to something that is not overly complicated or difficult. Indeed, some of the world's brightest minds are involved in the design of solid-rocket systems. Nevertheless, the challenge is extreme, failures still occur, and the gap be-tween scientific understanding and hardware design is large. Thus, solid-rocket motor design is an ideal focus for research devoted to advancing the state of the art in large-scale computational simulation of complex systems.At the Center for Simulation of Advanced Rockets, recently established at the University of Illinois at Urbana-Champaign, we're working toward detailed, integrated, whole-system simulation of solid-propellant rockets under normal and abnormal operating conditions. Meeting this daunting challenge requires a multidisciplinary team of engineers, physical scientists, and computer scientists to develop and implement the necessary mathematical models, algorithms, and software to build a virtual rocket. Performing the resulting simulated launch scenarios requires enormous computational capacity. Plans for achieving this ambitious goal call for a staged approach over the five-year period for which the CSAR was initially funded by the US Department of Energy's Accelerated Strategc Computing Initiative (see the sidebar, "CSAR, ASCI, and ASAP.") This article outlines our approach to t h~s merger of rocket and computer sciences.