Galileo's Scientific Traction

Article excerpt

Byline: Charles Rousseaux, THE WASHINGTON TIMES

The Galileo spacecraft wasn't carrying a yellow "Bacteria on Board" sign on it when it crashed into the planet Jupiter on Sunday following an extraordinary odyssey, but it could have been. After all, Galileo was built and launched in the 1980s, and the possibility it bears Earth-born bacteria that were borne on the long trip - including 14 years in space and exposure to Jupiter's intense radiation belts - is the reason scientists decided to crash the probe instead of leaving it in an orbit that would eventually decay.

Scientists were most concerned that Galileo's passengers could contaminate the life that could live in the briny oceans under the icy surface of Jupiter's moon Europa. Convincing evidence of those oceans - which could contain enough water to fill Earth's ocean basins twice - was one of Galileo's most significant finds on its voyage. Over the last few decades, scientists have realized that where there is liquid water, there could be life, no matter how inhospitable conditions otherwise.

Not long ago, respectable scientists would have waste-receptacled proposals suggesting bacteria could survive in chilly sunless seas; much less long voyages through the abhorrent vacuum of space. However, that former biological cornerstone has been shattered as scientists have found life not merely surviving, but actually enjoying extreme conditions that would make an Eco-challenger wince, whether high on frozen mountains or deep in the ocean. The New York Times science section recently ran a feature on heat-loving microbes living around hot water vents on the Earth's ocean floor, where temperatures are way above boiling.

The same drive to survive - and thrive - was shown by Galileo's operators, since the mission suffered several near mission-ending catastrophes. It was supposed to have been launched from a liquid-fuel powered rocket carried aboard the space shuttle. However, that rocket was thought to be an unacceptable risk after the Challenger disaster, and no other propulsion system packed sufficient push to put Galileo to the planet.

NASA engineer Roger Diehl eventually determined the probe would gain enough power if it was sent through an unorthodox series of gravity assist maneuvers, slingshotting around Venus once and the Earth twice before heading to Jupiter. Then another disaster unfolded, or more precisely, failed to unfold. Galileo's high-gain antenna failed to open, which meant information acquired by the craft could only be sent at a plodding rate - amounting to only a single picture a month. …