An artist's concept of Cassini during the flyby of Jupiter. Photo: NASA/JPL

A few of the 2,300 students from 13 states who have used a huge remote-control radio telescope to measure energy from Jupiter's radiation belts during the past six months will present their results May 4 to scientists at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The students' measurements span the period when NASA's Cassini spacecraft flew near Jupiter four months ago, so they are useful in the interpretation of radio measurements that Cassini made to map the invisible belts, said Dr. Michael Klein, a JPL radio astronomer and science adviser to the Cassini-Jupiter Microwave Observation Program.

Tracy Sibbaluca, a 14-year-old eighth grader from Detroit, looks forward to meeting the scientists, but even more to seeing the big radio-antenna dish in the Mojave Desert that she helped to run from a classroom computer at Detroit's University Public School.

"It gave me a lot of confidence because they trust kids like us with such a valuable telescope," said Arkira Jordan, 14, an eighth grader from Opelika, Ala. "I didn't like science so much before, but now I like it better."

Those two and 10 other students representing the larger group from 26 middle schools and high schools will tour the Goldstone Complex of JPL's Deep Space Network near Barstow while they are in California this week. The students used a dish antenna at Goldstone that is 34 meters (112 feet) in diameter. That dish, the Goldstone-Apple Valley Radio Telescope, served in Goldstone's main function of communicating with spacecraft for three decades, but was given a new role three years ago for student use coordinated by the Lewis Center for Educational Research, in Apple Valley, Calif.

One of Jordan's classmates at Opelika Middle School, 13- year-old Chase Cox, said, "When I think about what we're doing, it's amazing, because we were collecting data that scientists will be using years from now."

Opelika science teacher Farrell Seymore said the project has helped his students understand that science is a process of learning, not a set of facts to memorize. "When you are studying something real and it's not simulated, things don't always go the way you expect," he said. "That encourages the kids to use critical thinking skills and try to figure out what the problem is. It's a great experience for them." The Jupiter studies also played into lessons in mathematics, language skills and history, Seymore said.

Matthew Dillard, 14, a Detroit eighth-grader, said that the chance to be personally involved in research related to Cassini raised his interest in what the spacecraft discovers in coming years. Cassini will begin orbiting Saturn in 2004. The spacecraft will also release the Huygens probe to drop through the thick atmosphere of Saturn's largest moon, Titan. Cassini flew past Jupiter on Dec. 30, 2000, to gain a gravitational boost toward Saturn, and used that opportunity to take pictures and measurements of Jupiter and its surroundings.

Cassini's radar instrument, which shares the main antenna used for communications and is one of 18 science instruments on the orbiter and probe, was used in listen-only mode to measure radio emissions from high-energy electrons in radiation belts out past Jupiter's atmosphere. Those measurements allow mapping of the radiation sources in greater detail than possible from Earth-based observations. The belts are known to vary over time. Using the Goldstone-Apple Valley Radio Telescope, the students monitored the radiation belts from November to March to determine whether the belts were at a normal or unusual state of activity when Cassini mapped them. The results indicate the belts' activity was at a normal level when Cassini passed, but that some changes could be measured shortly afterwards, said JPL physicist Dr. Scott Bolton. "These measurements will be useful to help scientists learn more about Jupiter's radiation belts," he said.

The students will present their findings to Dr. Charles Elachi, team leader for the Cassini radar instrument, along with Klein, Bolton, Dr. Steve Levin, Dr. Michael Janssen and other JPL scientists. As of May 1, Elachi also will be JPL's new director. The students' visit is sponsored by the Lewis Center for Educational Research. "These students represent thousands who have collected valuable scientific information while gaining an exciting educational experience," said Jim Roller, the center's vice president for science and technology.

Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages Cassini for NASA's Office of Space Science, Washington, D.C.