NASA spacecraft barreling toward Jupiter for July 4 meetup

LOS ANGELES — A NASA spacecraft is on track to rendezvous with Jupiter after a nearly five-year journey.

The space agency said Thursday the encounter will occur on July 4. That’s when Juno will fire its main engine to slow down and slip into orbit around the biggest planet in the solar system.

Once in place, Juno will spend almost a year circling Jupiter’s poles and peering through clouds to study how the planet formed and evolved. Unlike Earth, which is a rocky planet, Jupiter is a gas giant made up mostly of hydrogen and helium.

Previous missions to Jupiter have relied on nuclear power sources this far out from the sun. Juno is unique because it has solar panels that are designed to face the sun during most of the mission.