HOUSTON -- The former director of the Jet Propulsion Laboratory identified Saturns largest moon Titan as a compelling target for future robotic exploration.

Humanitys first taste of Titans tantalizing organic chemistry is still several years away. NASAs Saturn-bound Cassini spacecraft is slated to fire the European Space Agencys tiny Huygens probe toward Titan in January 2005. The instrumented probe is expected to return valuable information about the organic chemical processes churning up Titans dark and hazy atmosphere. Scientists believe that Titans chemical composition makes the moon an enticing parallel to prebiotic Earth.

Speaking at a World Space Congress panel on the next 25 years of space science, Edward Stone, the former JPL center director, said that the first 40 years of space science has been marked by a broad survey of the solar systems stunning diversity of planets and processes. The next 25 years, he said, will be all about understanding the processes that lead to such great diversity.

"One vision for the next 25 years is to return to Titan after weve had this first look in January 2005," said Stone, who now teaches at the California Institute of Technology, also in Pasadena.

Stone said future missions to Titan might include the use of an instrumented balloon craft to further explore the moons surface and atmospheric chemistry.

"Ive got to believe that Titan will remain a focus of exploration for decades to come because of what it has to teach us about the organic chemistry of the early solar system," Stone said.

Other important exploration objectives for the next quarter century, according to Stone, include collecting surface samples from asteroids, comets, and Mars, finding a way to penetrate below the icy surface of the Jovian moon Europa, visiting Pluto and its Kuiper Belt neighbors, building observatories to find Earth-like planets around nearby stars and building a high-powered probe that travel beyond the solar system.