‘Burn complete, orbit obtained’: Juno mission ready to unlock Jupiter’s secrets

© NASA Jet Propulsion Laboratory
After an almost five year journey, the US space agency’s solar-powered Juno spacecraft has arrived on Jupiter's doorstep and is "ready to unlock" all Jupiter's secrets.

Jubilant scientists in NASA control room rose to standing ovation when Juno was confirmed to have entered Jupiter's orbit after the burning of the engine.

Now the spacecraft is expected to have slowed down to 1,212 miles per hour (542 meters per second), positioning itself safely in the orbit and re-orienting toward the sun to recharge its batteries.

Ahead of the final descent into Jupiter's orbit, scientists were on the edge of their seat hoping for Juno to complete the maneuver before it ran out of power. Once in orbit, Juno is to circle the planet 37 times over the next 20 months, flying some 3,100 miles (5,000 kilometers) from Jupiter’s surface.

"I'm really just nervous that the whole orbit insertion rocket burn is going to work enough to get us into orbit and then allow us to turn back to the sun before we run out of battery power," Scott Bolton, the principal investigator for Juno with the Southwest Research Institute in San Antonio said at a news conference ahead of the historic moment.

NASA expects to receive first images via JunoCam from Jupiter in a few days, as the spacecraft awaits “downlink” windows a “handful of times” as it orbits the distant planet.

Juno was forced to shut down its cam five days prior to the arrival, but now scientists eagerly await the images, including the one of the "Great Red Spot" – a raging storm three and a half times the size of Earth located in Jupiter's southern hemisphere.

“What Juno's about is looking beneath that surface,” Bolton said. “We've got to go down and look at what's inside, see how it's built, how deep these features go, learn about its real secrets.”

According to Bolton, the team of scientists “just did the hardest thing NASA's ever done.”

Juno was launched from Cape Canaveral Air Force Station on August 5, 2011. The mission of the spacecraft is to study the origin and evolution of Jupiter. Scientist hope to shed light on how much water there is in Jupiter's atmosphere. Juno will also be instrumental in measuring the composition, temperature, cloud motions and other properties of the planet.

READ MORE: Juno entering Jupiter's orbit: 5 things you need to know

In addition to mapping out Jupiter's gravity fields, Juno will help study Jupiter's magnetosphere near the planet's poles, with a special focus on the auroras – northern and southern lights.

Juno is the second spacecraft to orbit Jupiter, following the Galileo probe which orbited the planet in 1995-2003.

The day on Jupiter is about 10 earth hours and its year is about 12 Earth years. Its effective temperature is some 112 C and surface gravity - approximately 2.5 times Earth's. Its mass is some 318 times that of Earth’s.