Contact: Jane Platt

March 26, 1999

NASA'S Galileo Spacecraft Finds "Bottle Blonde" Chemical on Europa

The Galileo spacecraft is operating normally as it continues transmitting to Earth pictures and other science information gathered during its January 31 flyby of Jupiter's icy moon Europa. Transmission of the data, which was stored on Galileo's onboard tape recorder, will be completed on April 30.

During the next month, data transmission will be interrupted at times because the Sun's position roughly between Earth and Jupiter interferes with radio communications with the spacecraft. Galileo radio scientists are taking advantage of this opportunity to study Galileo's radio signal as it becomes distorted by the effects of the solar wind. This helps scientists learn more about the solar wind, a powerful flow of electrified particles emitted by the Sun.

Before and after the communications blackout, Galileo is transmitting data from various science observations. One of them is a 50-minute-long study by the instruments that gather nformation about magnetic fields. Scientists hope to learn more about how Europa interacts with Jupiter's vast magnetic field.

Other observations will tell scientists more about the surface texture and composition of Jupiter's largest moon, Ganymede, and help them tell the difference between various possible forms of water ice on Europa. The shape of ice crystals is dictated by the temperature at which the ice formed. Scientists believe Jupiter's icy moons, including Europa, would mostly have either cube-shaped ice crystals or non-crystalline, glassy ice because of the extremely low temperatures on those moons. If ordinary, six-pointed ice -- the type found in snow and the freezer section of a refrigerator -- is discovered, it could indicate that the ice was formed by the freezing of liquid water spewed out from a geyser. This is an intriguing prospect, because it might be yet another sign of a possible ocean beneath Europa's icy crust.

Galileo has gathered a wealth of information about Jupiter, its moons and its magnetic environment during the past three years. The spacecraft is currently halfway through a two-year extended Galileo Europa Mission, a follow-on to the primary mission that ended in December 1997.