The US space agency has successfully put a new probe in orbit around Jupiter - having left earth five years ago.
The Juno satellite will be used to learn more about the planet which is more than 1.5 billion miles away.
Scientists think the structure and the chemistry of its insides hold clues to how the planet formed four-and-a-half-billion years ago.
Rob Selby, site manager at Moog-Isp in Buckinghamshire, which built the engines for Juno, said: “This mission is about understanding the origins of the solar system.
“We have sent probes to Jupiter previously, but we didn’t get to look at the surface because of a cloud of gas and it couldn’t penetrate very well.
“Juno ducked beneath the clouds and will scan the surface of the planet.
“Because Jupiter is believed to be one of the first planets we will learn more about how the solar system began.”
No previous spacecraft has ever passed so close to Jupiter because of the intense radiation which could destroy a craft’s hardware.
But with a titanium shielding, Juno appeared unharmed and the mission will now begin, and will include repeat passes over the Jupiter’s clouds.