Artist's illustration of NASA's Juno spacecraft at Jupiter. The probe will enter orbit around the solar system's largest planet on July 4, 2016.

A NASA spacecraft now has Jupiter more squarely in its sights ahead of its July 4 arrival at the solar system's largest planet.

NASA's solar-powered Juno probe performed an engine burn Wednesday (Feb. 3), consuming 1.3 pounds (0.6 kilograms) of fuel to change its speed by about 0.7 mph (1.1 km/h). Juno was roughly 51 million miles (82 million kilometers) from Jupiter when it conducted the maneuver, agency officials said.

"This is the first of two trajectory adjustments that fine-tune Juno's orbit around the sun, perfecting our rendezvous with Jupiter on July 4 at 8:18 p.m. PDT [11:18 p.m. EDT; 0318 GMT on July 5]," Juno principal investigator Scott Bolton, of the Southwest Research Institute in San Antonio, said in a statement.

The second of these engine burns is scheduled to take place on May 31, NASA officials said.

The $1.1 billion Juno mission launched in August 2011. Its main goal involves mapping Jupiter's gravitational and magnetic fields in precise detail, to help scientists learn about the gas giant's structure, formation and evolution, mission team members have said.

Juno will perform its science work from orbit. The nominal mission plan calls for the 4-ton spacecraft to zip around Jupiter 33 times, coming within just 3,100 miles (5,000 km) of the planet's cloud tops once every 14 days, NASA officials said.

Juno carries three 30-foot-long (9 m) solar panels, which together hold a total of 18,698 individual solar cells. Such extensive light-collecting gear is necessary to power the spacecraft in the relatively dim environment around Jupiter, which orbits more than five times farther from the sun than Earth does.

Last month, Juno became the farthest-flung solared-powered probe in spaceflight history. The previous record was held by the European Space Agency's comet-chasing Rosetta spacecraft, which got a maximum of 492 million miles (792 million km) from Earth in October 2012.

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