PASADENA, Calif. (AP) – In a dramatic finale to its 14-year journey, NASA’s stalwart Galileo spacecraft headed for the conclusion of its $1.5 billion exploration of Jupiter on Sunday in a fiery plunge into the stormy atmosphere of the solar system’s largest planet.
The National Aeronautics and Space Administration said the aging craft would pass into the shadow of Jupiter at 3:42 p.m. EDT and enter its atmosphere seven minutes later.
Streaking downward at nearly 108,000 mph, the 3,000-pound spacecraft was expected to be destroyed by the tremendous heat and friction of its passage through the atmosphere.
The suicide dive concludes one of NASA’s most troubled yet ultimately successful planetary missions.
Galileo completed 35 orbits of Jupiter, allowing it to study the gas giant and its moons more intensely than had any other spacecraft.
The 14,000 photos and countless measurements it sent to Earth provided tantalizing clues suggesting three of those moons – Callisto, Europa and Ganymede – have liquid oceans. That’s charged the imagination of scientists who speculate the salty water could harbor extraterrestrial life.
The probe’s cameras also caught Io, the most volcanically active body in the solar system, as it belched lava and plumes of dust and gas.
Galileo is the first planetary spacecraft NASA has crashed on purpose since it steered the Lunar Prospector into the Earth’s moon in 1999.
It is not the first, however, to dive into Jupiter: A probe released by Galileo did so in 1995, collecting data about the planet’s chemical composition, winds, clouds and radiation for nearly an hour before it was destroyed.
NASA opted to destroy Galileo to keep it from slamming into Europa and contaminating it with any terrestrial microbes the spacecraft might have carried since launch. The vehicle was nearly out of steering propellant that would have allowed scientists to guide it away from the moon.
Were Earth bacteria to gain a toehold on Europa, they could compromise attempts to probe the moon for indigenous life, scientists fear.
The mission was plagued with glitches but still met 70 percent of its science objectives.
The biggest challenge was the failure of the spacecraft’s umbrella-like main antenna, which failed to unfurl two years after launch. That forced NASA to rely on a smaller antenna, which squeezed the amount of data Galileo could return to Earth.
The intense radiation found close to Jupiter also took a toll on the electronics of the spacecraft, itself powered by radioactive plutonium.
Adversity had been a part of the mission from the start.
Congress approved the project in 1977, but it took another dozen years to launch it. The 1986 space shuttle Challenger disaster, which grounded NASA’s shuttle fleet, was partly to blame.
Galileo finally left Earth in 1989, catching a ride to orbit aboard the shuttle Atlantis.
After Atlantis released Galileo, the spacecraft traveled more than 2.8 billion miles.
En route to Jupiter, Galileo was the first spacecraft to fly past an asteroid, and two years later it was the first space probe to spy a tiny moon in orbit around another space rock.
NASA intends to return to Jupiter in a decade with another unmanned spacecraft called the Jupiter Icy Moons Orbiter.
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On the Net:
Galileo Project: http://www.jpl.nasa.gov/galileo/
AP-ES-09-21-03 1537EDT
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