Sarah Keegan
Headquarters, Washington       August 2, 2002
(Phone: 202/358-1902)

RELEASE: 02-148

NASA SELECTS TWO DESIGN TOOLS AS SOFTWARE OF THE YEAR

     NASA has selected two software innovations that save 
significant money and time over more traditional methods as 
co-winners of its 2002 Software of the Year Award. Each team 
of developers will receive an award of $50,100 in cash from 
the NASA Administrator. Both software design tools have been 
adopted by other government agencies, private industry and 
academia.

The DSMC Analysis Code (DAC) software package, developed at 
NASA's Johnson Space Center in Houston, models the flow of 
low-density gases over flight surfaces. DSMC stands for 
Direct Simulation Monte-Carlo and is a simulation method. The 
software provides insight into the interaction of spacecraft 
and rarified environments, such as those encountered during a 
spacecraft entry into an atmosphere at high altitudes.

DAC was used to provide information to help optimize and 
verify maneuvers of spacecraft that orbited Mars after they 
were slowed by repeatedly skimming through that planet's 
atmosphere instead of relying on thrusters for deceleration. 
The technique enabled the spacecraft to be lighter, which 
reduced launch costs.

Another application is analysis of plume impingement, the 
effects of firing of thrusters by one spacecraft on another 
spacecraft nearby. An early use of the software was analyzing 
the effect of space shuttle thruster firings as the vehicle 
approached the Russian space station Mir during the Shuttle-
Mir program. This has since led to significant changes in 
docking procedures and venting operations aboard the new 
International Space Station.

DAC is in use at most NASA centers and within the U.S. 
military, and is beginning to be employed by the aerospace 
industry for advanced applications involving high-altitude 
vehicles. In addition, the unique flow-solvers adapted to DAC 
allow the software's use in applications in which the object 
within the flow field is very small, such as MEMS (micro-
electromechanical systems) and nanotechnology devices.

The DAC team is led by by Gerald J. LeBeau, and includes 
Forrest E. Lumpkin, Katie A. Jacikas, and Phil C. Stuart, of 
Johnson; and Richard G. Wilmoth and Christopher E. Glass, of 
NASA's Langley Research Center in Hampton, Va.

The NASA Software of the Year co-winner -- Cart3D -- is an 
aerodynamic simulation tool on which work began in 1992 at 
NASA's Ames Research Center, located in California's Silicon 
Valley. This software package provides designers and 
engineers with an automated, highly accurate computer-
simulation suite that streamlines the conceptual and 
preliminary analysis of both new and existing aerospace 
vehicles.

Cart3D provides a revolutionary approach to computational 
fluid dynamics -- the computer simulation of how fluids and 
gases flow around an object. Before the advent of this 
software, the basic computational tool -- the grid layout 
used in analyzing designs of airplanes and spacecraft -- had 
to be hand-generated and required months or even years to 
produce for complex models. Cart3D automates grid generation 
to a remarkable degree, enabling even the most complex 
geometries to be modeled 100 times faster than before.

Simulations generated by Cart3D help identify and fix 
problems in military transport aircraft and helicopters. 
Cart3D's novel approaches allow simulation of complex 
geometries in fields other than aerospace ranging from 
astrophysics to computer science to electromagnetics. The 
software is in wide use by universities and corporations, as 
well as most NASA centers and other government agencies, for 
a plethora of applications.

Cart3D was developed jointly by Michael Aftosmis and John 
Melton of Ames, and Professor Marsha Berger of the Courant 
Institute, New York University.

Each year the NASA Chief Engineer sponsors the NASA Software 
of the Year competition -- an international competition for 
the largest award for software excellence -- with technical 
support from the agency's Inventions and Contributions Board. 

More information about the winners may be found at:
http://icb.nasa.gov/swoy2002/

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