Pluto-Bound Space Probe Eyes Jupiter

Jan. 12, 2007 — Less than a year after leaving Earth, a spacecraft bound for Pluto is approaching Jupiter for a six-month series of observations.

New Horizons lifted off from Cape Canaveral Air Force Station in Florida on Jan. 19 for a nine-year voyage to Pluto. This week, mission scientists began a mini-campaign to study Jupiter.

The probe's closest approach will come on Feb. 28, but observations of Jupiter's icy moons, its turbulent atmosphere and powerful magnetic field will continue until June.

The first of about 700 images was an infrared shot of Callisto, the third largest moon in the solar system. NASA's Galileo mission to Jupiter, which ended in September 2003, showed evidence of an ocean beneath Callisto's ice-covered crust.

During the encounter, New Horizons also will be training its instruments on sister moons Io, Europa and Ganymede to flesh out maps produced by the Galileo satellite.

Galileo had a faulty main antenna, which limited the amount of data that could be relayed back to Earth. Scientists hope that New Horizon's high-speed communications system will help them learn more about the giant moons. Io, for example, has active volcanoes and Europa likely sports an underground — and perhaps life-bearing — sea.

The probe, which will use Jupiter's gravity field to slingshot itself onward to Pluto, also is scheduled to make a long trek down the length of Jupiter's magnetic tail, which extends for tens of millions of miles beyond the planet. The tail stems from Jupiter's vast and dynamic magnetic field, which is buffeted and shaped by the high-speed river of charged particles constantly flowing from the Sun.

"This is an unprecedented opportunity," New Horizons principal investigator Alan Stern, with the Southwest Research Institute in Boulder, Colo., said in an interview with Discovery News. "It's never been done on a giant planet before."

Other highlights of New Horizon's Jupiter tour include a first-time close-up look at a storm known as the Little Red Spot, which formed after Galileo's demise.

"There's a long list of things we'll be able to do that have never been done before," Stern said.

New Horizons, which is now about five times as far from the Sun as Earth, will come as close as 1.4 million miles, or 2.3 million km, to Jupiter. Once the studies of the giant planet are complete, New Horizons will be put into hibernation to save money and wear-and-tear on the systems.

NASA plans to unveil New Horizon's first images of Jupiter at a press conference next week.