Galileo spacecraft camera will take its last pictures
Wednesday, January 16, 2002
LOS ANGELES -- Since 1989, the camera on NASA's Galileo spacecraft has captured a comet slamming into Jupiter, volcanoes erupting on one of its moons and the first known moon orbiting an asteroid.
On Thursday, the camera will snap its last pictures. Galileo will make its final flyby of one of Jupiter's major moons when it sweeps within 62 miles of Io.
The mission budget does not cover any further pictures.
Galileo will continue making other scientific observations until September 2003, when the $1.4 billion spacecraft is expected to slam into Jupiter in a spectacular finale. But the 70 photographs to be transmitted to Earth over the next three months will be the last.
They will be a bittersweet reminder of a mission that was supposed to provide scientists -- and the world -- with motion picture-like images of Jupiter's vibrant atmosphere. Because of computer glitches and other problems, Galileo never did produce the movie-quality images, but it still provided stunning and scientifically valuable pictures.
During 32 orbits of Jupiter, Galileo studied the planet-size moons Ganymede, Callisto, Europa and Io.
Among its discoveries was evidence of liquid oceans beneath the surfaces of Europa and Callisto that could harbor life. The spacecraft also kept tabs on some of the dozens of hot, active volcanoes on Io.
In all, Galileo has returned about 14,000 images to Earth.
"It will be sad when we get to the end, but at the same time, looking back at its history, you can be quite proud of the mission," Eilene Theilig, Galileo project manager at NASA's Jet Propulsion Laboratory.
The spacecraft was launched in 1989 from the space shuttle Atlantis and arrived in orbit around Jupiter six years later.
Originally, Galileo was to have used its high-gain antenna to zip data back to Earth at 134 kilobits per second -- more than twice the rate of a typical home dial-up modem. Scientists hoped to capture hundreds of thousands of images of Jupiter's atmosphere, stitching them together to create elaborate movies.
Instead, the antenna jammed during its deployment in 1991, forcing scientists to rely on the probe's low-gain antenna and its pokey rate of 160 bits per second.
The glitch was compounded by radiation damage to the camera and other spacecraft components.
Still, the camera piled up the images.
In 1993, Galileo captured the asteroid Ida at close range, allowing scientists to discover that the space rock had a tiny moon of its own, which they named Dactyl. A year later, Galileo watched as fragments of the comet Shoemaker-Levy 9 slammed into Jupiter and exploded in its atmosphere.
During Thursday's flyby, Galileo will make its closest pass yet to any of Jupiter's moons. Its camera should be able to capture features on Io's surface as small as 33 feet across. It will also snatch the first peek at the moon's Jupiter-facing hemisphere since the Voyager mission in 1979.