2002 Award Co-Winners
The DSMC Analysis Code (DAC)
Lead NASA Center:
Johnson Space Center (JSC)
DAC software provides NASA scientists and engineers with an easy to use, state-of-the-art, three-dimensional, implementation of the Direct Simulation Monte Carlo (DSMC) method that can be applied to a broad base of critical Agency low-density flow problems. DSMC, which performs a direct physical simulation of a gas at the molecular level, is widely recognized as the de facto standard for computationally predicting low-density flows.
Some examples of use in critical NASA applications include defining a vehicle's aerodynamics and aerothermodynamics for the initial portion of a reentry into an atmosphere, aerobraking maneuvers such as those recently employed by planetary probes in the rarefied portion of a planet's atmosphere, rarefied environments generated on-orbit through the use of reaction control system (RCS) thrusters for maneuvering, the venting overboard of waste gases and outgassing of materials on-orbit. Other rarefied gas dynamics applications would include deposition of electrical pathways for microelectronic circuit boards, and fluid mechanics applications for Micro Electro-Mechanical Systems (MEMS) devices, and many others.
DAC has been used to predict the high-altitude aerodynamic characteristics of the experimental vehicles, including the aerodynamic increments associated with the interaction of the free stream and the vehicle's attitude control system (ACS). The high-fidelity predictions are also able to characterize self-impingement effects when the ACS system is used on orbit, and the resultant efficiency of each jet. DAC has also been used to predict the high-altitude aerodynamic characteristics and aerothermodynamic environments of operational NASA vehicles including Mars Pathfinder, Stardust, Genesis, Mars Global Surveyor, Mars Climate Orbiter and Mars Odyssey.
For the Mars Global Surveyor and Mars Odyssey missions, DAC aerodynamic predictions, in conjunction with flight data, prepared atmospheric density profiles for Mars that were used for daily operational planning during aerobraking and to better define the atmosphere for future missions. In addition it explained the significant unforeseen attitude changes caused by overboard venting on the ISS, assesses operational issues associated with servicing of the Hubble Space Telescope (HST), characterizes candidate vehicles for human missions to Mars, and performs key benchmark calculations of fundamental flow phenomena.
Lead NASA Center:
Ames Research Center (ARC)
Cart3D is a high-fidelity geometry processing and flow analysis package that automates conceptual and preliminary aerodynamic design. Cart3D's approach to geometry processing and space discretization has had a worldwide impact on the simulation of complex geometries in fields outside of aerospace ranging from astrophysics to computer science and electromagnetics.
The work of the Cart3D development team consisting of over 25 technical papers, lecture series, course notes, and book chapters has been cited in more than 100 different technical and refereed journal articles from around the world. The current licensee of the Cart3D package is an industrial simulation provider, ICEM/CFD, a subsidiary of ANSYS, Inc. for use in the aerospace, electronics/electromagnetics, automotive, turbomachinery, and industrial process industries.