NASA $1.1 billion probe set to launch for Jupiter

The robotic probe called Juno is scheduled to spend one year cycling inside Jupiter's deadly radiation belts, far closer than any previous orbiting spacecraft, to learn how muchwater the giant planet holds, what triggers its vast magnetic fields and whether a solid core lies beneath its dense, hot atmosphere.

"The main goals of Juno are to study the origin of Jupiter, and it represents giant planets as we know around our stars and other stars, it holds a lot of key secrets" said Scott Bolton, the mission's principal investigator from the Southwest Research Institute in San Antonio.

Scientists believe Jupiter was the first planet to form after the birth of the sun, though exactly how that happened is unknown. One key piece of missing data is how much water is inside the giant planet, which circles the sun five times farther away than Earth.

Juno's journey to Jupiter will take five years. Upon arrival in July 2016, Juno will thread itself into a narrow region between the planet and the inner edge of its radiation belt. The solar-powered probe will then spend a year orbiting over Jupiter's poles, coming as close as 3,100 miles (5,000 km) above its cloud tops.

Only an atmospheric probe released by Galileo, NASA's last Jupiter spacecraft, has come closer, though that spacecraft was able to relay data for only 58 seconds before succumbing to the planet's crushing pressure and intense heat.

Juno's electronic heart is protected in a vault of titanium, but it too will fall to the harsh Jovian radiation environment after about a year. Juno's last move will be to dive into the planet's atmosphere to avoid any chance of contaminating Jupiter's potentially life-bearing moons.

Juno's launch is scheduled for Aug. 5. The spacecraft was built by Lockheed Martin Astronautics of Denver, Colorado. The mission, the second in NASA's lower-cost, quick-turnaround New Frontiers planetary expeditions, will cost $1.1 billion.