Jupiter poses radiation problem

Scientists in the US say radiation on Jupiter is far more severe than previously estimated.

Their findings raise concerns about how well future space probes could survive close to the giant planet.

NASA's Cassini spacecraft used its antenna to measure natural radio emissions coming from Jupiter's radiation belts when it flew past the planet in December.

The data, not measurable from Earth, nor by any previous spacecraft to visit Jupiter, showed lower levels of the highest-energy electrons, but forced scientists to increase their estimates of the amounts of electrons with slightly lower energy levels.

While not as deadly, the slightly less energetic electrons still pose a formidable threat to the electronics aboard any spacecraft that ventures within 200,000 miles of Jupiter.

Scott Bolton, a physicist at NASA's Jet Propulsion Laboratory, commented: "This has implications not only for understanding the physical processes in the radiation belts, but also for designing any spacecraft for future exploration close to Jupiter."

NASA has no firm plans to send a spacecraft close in to Jupiter, although scientists have proposed a mission called INSIDE Jupiter that would launch in 2003 and reach the planet in 2011. During its 15-month mission, the probe would travel within 2,500 miles of the planet.

Scientists have long known about Jupiter's harsh radiation environment. NASA's Galileo spacecraft has endured more than three times the radiation exposure it was designed to withstand since arriving in orbit around Jupiter in 1995.