University Of Maryland Students Are In Satellite 'Drivers Seat'

For the past year, laboratory director David Schmidt and his students have been collaborating with NASA's Goddard Space Flight Center to develop the capability for real-time mission support of the SAMPEX as well as other NASA spacecraft. Their work has included the development of mission-analysis software and computer and communication interfaces. Maryland's Flight Dynamics and Control Laboratory took over sole control of the SAMPEX satellite on a trial basis in May and now officially has been handed the satellite's "reins." The laboratory performs orbit determination, orbit prediction, scheduling of ground-station access times, ground tracking and other "events," attitude determination, and monitoring of the satellite's sensors.

"Taking over navigational and orbital control of the SAMPEX is exciting both because it is an important part of a unique new research program that our laboratory is developing and because our work with NASA on this project could be a prototype for the agency in turning over mission control responsibilities for other spacecraft in the future," said Schmidt, a professor of aerospace engineering in the university's highly regarded A. James Clark School of Engineering.

"The goal of our laboratory's new program is to develop advanced automation technologies for spacecraft navigation and mission control," Schmidt said. "Operating the SAMPEX spacecraft gives us an actual test bed that we can use to evaluate new algorithms, software tools and other technologies developed in the program."

At the same time, he said, the procedures, techniques, and software that the students are developing as part of the SAMPEX work could be used or adapted by other universities interested in providing mission control services to NASA.

According to NASA's Tom Stengle, head of the Flight Dynamics Analysis Branch at Goddard, there are a few other cases where the agency has turned flight operations for a spacecraft over to a university. "However, what's different in this case is that here it is entirely graduate and undergraduate students who are doing the [mission control] work," Stengle said. "What's especially neat about [the University of Maryland's work on SAMPEX] is that the students are learning about this area in class and then going over and putting that learning into practice."

Launched July 3, 1992, the SAMPEX is a sun-pointed satellite that currently is in an almost-circular low-Earth orbit. The SAMPEX mission will end when the spacecraft re-enters the atmosphere in 2002. To study radiation striking the Earth's atmosphere, SAMPEX investigates ions -- atoms stripped of one or more negative electrons -- of such chemical elements as oxygen and iron. These radiations come from different places in the solar system and the Galaxy, and they carry information about the site of their origination. Researchers want to know more about these radiation types since they can provide important information about the Sun and its interaction with the Earth, about the local interstellar medium, and about the violent explosions in the galaxy called supernovae. The scientific work of SAMPEX is directed by university physics professor Glenn Mason, who recently began serving a three-year term as a member of the National Academy of Sciences/National Research Council Committee on Solar and Space Physics.

The SAMPEX work of the Flight Dynamics and Control Laboratory is just one part of research that involves both theoretical and applied investigations in aeronautics and astronautics. Graduate and undergraduate students in engineering and computer science conduct research in areas that include atmospheric flight dynamics, astrodynamics, optimal flight guidance, and flight- control systems design and digital control systems. Lab research programs are conducted in collaboration with several NASA centers, the U.S. Navy, a variety of industry partners, and the University of Maryland. Programs range from orbit determination for the SAMPEX and other spacecraft to integrated flight and propulsion control for advanced aircraft and for air-breathing launch vehicles.

Editor's Note: The Web site address for the University of Maryland's Flight Dynamics and Control Laboratory is http://hubble.umd.edu/. For NASA's SAMPEX satellite home page, the URL is http://lepsam.gsfc.nasa.gov/www/sampex.html.