The far side of the moon, last photographed by Apollo astronauts two decades ago, was captured on film again by the Galileo spacecraft when it zoomed past the Earth on its long voyage to Jupiter.
"It's staggering to realize we've been neglecting our own satellite," said Torrence Johnson, Galileo's chief scientist at NASA's Jet Propulsion Laboratory.Astronauts with the 1969-1972 Apollo lunar missions photographed the back side of the moon, but Johnson said Thursday the last good pictures before Galileo were made by unmanned lunar orbiters during the 1960s.
Galileo passed the moon after it swooped 597 miles above the southwest Atlantic Ocean on Saturday. It used Earth's gravity as a slingshot to help expand the spacecraft's orbit around the sun so it can reach Jupiter in 1995. It used Venus for the same purpose last February and will fly past Earth again in December 1992.
The planetary encounters are meant solely to help propel Galileo on its $1.4 billion mission to Jupiter. But scientists took the opportunity to use the spacecraft to study Venus and Earth in dress rehearsals for exploring Jupiter.
Three of Galileo's new photographs of the moon and Earth were released Thursday by the National Aeronautics and Space Administration as Galileo zoomed away from Earth, snapping more pictures of its home planet from a distance of 2.33 million miles.
One photo shows the crescent moon, while another shows Mare Orientale, a 550-mile-wide meteorite impact crater on the far side of the moon, which is always pointed away from Earth. Because of the way the moon orbits, only five-eighths of its surface can be seen from Earth.