NASA'S Juno spacecraft capped a five-year journey to Jupiter on Monday with a do-or-die engine burn that looped it into orbit to probe the origins of the biggest planet in the solar system and how it impacted the rise of life on Earth, the U.S. space agency said.
Juno fired its main engine beginning at 11:18 p.m. EDT/0318 Tuesday GMT, slowing the spacecraft so it could be captured by the planet's gravity.
Launched from Florida nearly five years ago, Juno needed to be precisely positioned, ignite its main engine at exactly the right time and keep it firing for 35 minutes to become only the second spacecraft to orbit Jupiter.
If anything went even slightly awry, Juno would have sailed helplessly past Jupiter, unable to complete a $1 billion mission.
Once in position to begin its 20-month science mission, Juno will fly in egg-shaped orbits, each one lasting 14 days, to peer through the planet's thick clouds, map its gargantuan magnetic field and probe through the crushing atmosphere for evidence of a dense inner core.
The probe also will hunt for water in Jupiter's thick atmosphere, a key yardstick for figuring out how far away from the sun the gas giant formed.