VOYAGER MISSION HIGHLIGHTS

In 1977, two unmanned Voyager spacecraft, designed and built by the Jet Propulsion Laboratory, were launched on reconnaissance missions to the outer planets. In 1979, Voyagers 1 and 2 sent back spectacular images of the Jovian system and made startling discoveries. Giant volcanoes spew molten sulfur hundreds of kilometers above the surface of lo, one of Jupiter's four largest moons, while Europa, Ganymede, and Callisto each have diverse surfaces. Three tiny moons were found near a thin ring of dust particles encircling the planet, and cloud-top lightning bolts and polar auroras light up the Jovian night skies.

The Voyagers traveled on to Saturn encounters in 1980 and 1981, respectively. The rings were more complex than scientists could have imagined. Although Saturn's colors are more muted than Jupiter's, storms are still visible in the cloud tops. A thick atmosphere of nitrogen and methane surrounds Titan, Saturn's largest moon, and photochemical hazes hide its surface. After its close swing past Titan, Saturn's gravity forced Voyager 1 up and out of the ecliptic plane, and the spacecraft is now on its way out of our solar system.

Mission planners took advantage of the opportunity to send Voyager 2 on to Uranus. Arriving at Uranus in 1986, Voyager 2 found a cold planet with a remarkably featureless atmosphere. The spacecraft discovered ten small moons and two new rings at Uranus. Miranda, one of the five larger moons, has one of the most complex surfaces yet seen in the solar system. Voyager 2's final planetary encounter took place on August 25, 1989, when the spacecraft sailed within 3000 miles of the cloud tops of Neptune's north pole. Five hours later, Voyager 2 swept past Triton, a cold, bright moon where volcanoes may spew ice particles into the thin nitrogen atmosphere. The spacecraft discovered six new moons and a number of rings at Neptune. Now Voyager 2 is also heading out of the solar system, diving below the ecliptic plane.

Data from both Voyagers may be received well into the next century as they search for interstellar space. The Voyager Project is managed for NASA by the Jet Propulsion Laboratory.