galileo_jupiter_000507 PASADENA, Calif. NASA may squeeze more science out of its
aging Galileo spacecraft before sending the $1.4 billion probe crashing into Jupiter to avoid contaminating the planets moons.A recent report by the National Research Councils Space Studies Board seconds NASAs preliminary plans
to re-route the spacecraft so it impacts Jupiter, possibly as early as December 2002. 
Watch the video animation of Galileo spacecraft approaching Io.
However, the boards
Committee on Planetary and Lunar Exploration (COMPLEX) supports a NASA proposal to first send Galileo flying by two of Jupiters moons, Io and Amalthea, which could delay the spacecrafts destruction to 2003 or even 2004.Regardless of when, it is almost certain Galileo will end its days with a suicide dive through Jupiters atmosphere. There, both it and any terrestrial organisms that may have stowed away on the robotic probe would be destroyed.
NASA has received at least one suggestion that it leave Galileo in orbit around Jupiter for the delight of future space archeologists. However, the American space agency does not want to risk the spacecraft hitting any of one of three of the planets moons that could harbor extraterrestrial life.
NASA's Galileo spacecraft Credit: NASA/JPL/Caltech
"It would be nice to leave it orbit around Jupiter, but you cant guarantee itll stay there forever," said David Smith, the COMPLEX study director.
Chief among the targets to be avoided is Europa, where scientists believe a global ocean sloshes below the ice cap that paves the moons surface. Conceivably, any microbial organisms stowed away aboard Galileo since its launch in 1989 could contaminate that ocean.
"The bottom line is, there are not orbits that guarantee you wouldnt hit Europa at some future date," said John Rummel, NASAs planetary protection officer. "So put it somewhere where you dont have to worry about it."
~
How soon NASA will do that is still open for debate. Of the four scenarios on the table, the most conservative would dispatch Galileo toward
Jupiter this December, impacting the planet exactly two years later.But that would curtail the probes chance at gathering more science data, leading the board to recommend NASA delay setting Galileo on any collision course for a full year, until late 2001.
Galileo captured images of Jupiter's volcanic moon Io.
The delay would allow Galileo to fly by the moon Amalthea once, giving scientists a shot at estimating its mass and density, and Io three times, allowing them to probe the nature of its magnetic field. NASA had hoped to make the latter observations during an earlier Io flyby, but the spacecraft went into so-called "safe mode" prior to the encounter, scrubbing the shot at gathering data.
The delay could mean a 20-percent increase in the amount of radiation Galileo would have to absorb a number that could spell trouble for its instruments. Were the spacecraft to cease functioning, NASA would lose the ability to steer it away from
Europa and other Jovian satellites."Its an extra year in which something could go wrong," Smith said of the spacecraft, which has already taken on three times as much radiation as its design specified. "Its slightly worrisome, but Galileo has done very well. Its performance is excellent."
A decision on which course to take could come as early as next month.
In the meanwhile, scientists are gearing up for a series of joint observations of Jupiter that Galileo will make with
Cassini when the latter spacecraft swings by the planet in December in a slingshot maneuver that will speed it on its way to Saturn.
advertisement
