- The Washington Times - Tuesday, September 23, 2003

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. However, NASA engineers fixed that problem by increasing the sensitivity of the Deep Space Network so signals from Galileo’s low-gain antennas could be received. They also fully rewrote Galileo’s software — from 400 million miles away — which allowed it to compress and then slowly send the information it collected. The solutions NASA engineers found for those and several other problems allowed Galileo to explore Jupiter’s miniature solar system for eight years, far longer than anyone anticipated.

As a consequence, Galileo became one of NASA’s most successful missions. En route to Jupiter, it became the first spacecraft to fly near an asteroid (Gaspra in 1991) and the first to discover an asteroid (Ida) with its own moon. It also gave scientists a direct view of comet Shoemaker-Levy’s impact into Jupiter in 1994.

While those were eye-openers, Galileo was just getting started. It dropped an probe into Jupiter’s atmosphere that sampled the planet’s gases for almost an hour during its 124-mile trip downward, discovering the planet is hotter and dryer than anyone anticipated. It made multiple passes by each of the four large moons — Europa, Io, Callisto and Ganymede — discovered by Galileo’s namesake in the 1600s. It found evidence of liquid water on Callisto and Ganymede; found the hottest volcanoes in the solar system on Io; and discovered Ganymede has a magnetic field, the first moon of a planet known to do so. Galileo also found 21 additional small moons orbiting Jupiter.

With Galileo gone, scientists expect to examine the surface of Mars through the electric eyes of the Mars Exploration Rovers when they land next January. They then hope to start uncovering some of the secrets of the planet Saturn and its murky moon Titan through the sensors of the Cassini-Huygens spacecraft when it arrives next July.

Galileo’s success shows life can be extremely successful under extremely stressful conditions. (Newspaper deadlines are usually met with less desirable results.) The same could be happening with NASA’s manned program, if its political leaders would give it a direction and a mission. Should that happen, flesh and blood might be traveling to Mars and beyond, instead of blind bacteria. By that time, given the fickleness of fashion, the spacecraft will probably be outfitted with the again trendy “Baby on Board” signs.

Charles Rousseaux is an editorial writer for The Washington Times.

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