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Galileo wakes from radiation-induced coma
By Richard Stenger
(CNN) -- An aging Jupiter probe that shut down during its final and most daring scientific mission has resumed normal operations, according to NASA. The Galileo spacecraft, which went silent November 5 after making its closest approach to Jupiter, is now in good working order, except for its tape recorder, mission scientists said this week. The instrument stored data recorded during the flyby, which brought Galileo within 44,500 miles (71,500 kilometers) of Jupiter's visible clouds. "It appears that the tape recorder has taken a hit from the intense radiation Galileo passed through. Our efforts to restore the tape recorder may continue for a few weeks," said Eilene Theilig, lead Galileo scientist at NASA's Jet Propulsion Laboratory in Pasadena, California. The descent, the most dangerous since Galileo arrived in the giant planet system seven years ago, took the ship deep into the dangerous radiation belts enveloping Jupiter. Galileo, which has endured four times as much radiation as it was designed to withstand, shuts down automatically when faced with high radiation levels, a reflexive response called "safe mode" intended to protect its sensitive electronics. The $1.4 billion craft has survived other deep forays into the radiation belts, but the one in November subjected it to twice as much radiation as any previous encounter. The repeated energy bathes have taken a toll in recent years. Galileo's camera is now shuttered and its tape player has become stuck several times. NASA engineers have always managed to unblock the tape player, but diagnostic tests suggest that the current problem is different.
They hope to fix the recording device to download data from the November 5 dive, which took Galileo within 100 miles (160 kilometers) of the tiny inner moon Amalthea and inside Jupiter's little studied "gossamer" ring, an extremely faint and diffuse debris band outside the planet's main ring. The observations include information about dust levels, charged particles and possibly the composition and density of Amalthea, an oddly shaped satellite about 155 miles (250 kilometers) wide. Whether the data is recovered or not, Galileo, nearly spent of fuel, remains on a collision course with Jupiter in September 2003. The fatal plunge is to ensure that the bus-sized robot ship does not strike and contaminate the large moon Europa, thought to possess a vast subsurface ocean that could harbor microbial life.
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