The piano-sized New Horizons spacecraft trained seven cameras and sensor on the solar system's largest planet as it used Jupiter's gravitation field to help propel itself deeper into space and trim three years from its travel time to Pluto.

Getting closer to Jupiter than any previous probe -- 1.4 million miles (2.25 million kilometers) away on February 28 -- New Horizons produced beautiful clues to how the system of the largest planet functions.

It grabbed the clearest images ever of the Jovian ring system which showed a series of unexpected arcs and clumps of dust, with the tiny inner moons Metis and Adrastea appearing to shepherd the materials around the rings.

"We're starting to see that rings can evolve rapidly, with changes detectable during weeks and months," said Jeff Moore, New Horizons Jupiter Encounter science team leader.

"We've seen similar phenomena in the rings of Saturn."

It also got the closest look at the Little Red Spot, Jupiter's second largest storm which is about 70 percent of the Earth's diameter. The Little Red Spot formed when three smaller storms merged during the past decade and began turning red about a year ago.

"This is our best look ever of a storm like this in its infancy," said Hal Weaver, from the Johns Hopkins University Applied Physics Laboratory, which built and operates the New Horizons spacecraft.

"Combined with data from telescopes on and around Earth taken at the same time New Horizons sped past Jupiter, we're getting an incredible look at the dynamics of weather on giant planets."

New Horizons made nearly 700 observations over the course of several weeks and has already sent back about 70 percent of the 34 gigabits of data, radioed to NASA's largest antennas over more than 600 million miles (1,000 million kilometers). It was a successful "stress test" of the spacecraft and team, NASA said.

"We can run simulations and take test images of stars, and learn that things would probably work fine at Pluto," said John Spencer, deputy lead of the New Horizons Jupiter Encounter Science Team.

"But having a planet to look at and lots of data to dig into tells us that the spacecraft and team can do all these amazing things. We might not have explored the full capabilities of the spacecraft if we didn't have this real planetary flyby to push the system and get our imaginations going."

New Horizons is expected to reach Pluto in July 2015.

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