Juno probe enters into orbit around Jupiter
The US space agency has successfully put a new probe in orbit around Jupiter.
The Juno satellite, which left Earth five years ago, had to fire a rocket engine to slow its approach to the planet and get caught by its gravity.
A sequence of tones transmitted from the spacecraft confirmed the braking manoeuvre had gone as planned.
Receipt of the radio messages prompted wild cheering at Nasa's Jet Propulsion Laboratory in Pasadena, California.
"All stations on Juno co-ord, we have the tone for burn cut-off on Delta B," Juno Mission Control had announced. "Roger Juno, welcome to Jupiter."
Scientists plan to use the spacecraft to sense the planet's deep interior. They think the structure and the chemistry of its insides hold clues to how this giant world formed some four-and-a-half-billion years ago.
Engineers had warned in advance that the engine firing was fraught with danger.
No previous spacecraft has dared pass so close to Jupiter; its intense radiation belts can destroy unprotected electronics.
One calculation even suggested the orbit insertion would have subjected Juno to a dose equivalent to a million dental X-rays.
But the probe is built like a tank with titanium shielding, and the 35-minute rocket burn appeared to go off without a hitch.
"Nasa did it again," said an elated Scott Bolton, Juno's principal investigator. "That says it all to me. And I'm so happy to be part of the team that did that. I mean this team has worked so hard and we have such great people. And it's almost like a dream coming true right here."