Juno (spacecraft) - Launch Timeline

Launch Timeline

The Atlas V (AV-029) Russian-designed RD-180 main engine, powered by kerosene and liquid oxygen, was started and underwent checkout 3.8 seconds prior to the ignition of five strap-on solid rocket boosters (SRBs). Following SRB burnout, approximately 1 minute 33 seconds into the flight, two of the spent boosters fell away from the vehicle followed 1.5 seconds later by the remaining three. When heating levels had dropped below predetermined limits, the payload fairing that protected Juno during transit through the thickest part of the atmosphere separated, about 3 minutes 24 seconds into the flight. The Atlas V main engine cut off 4 minutes 26 seconds after liftoff. 16 seconds later, the Centaur second stage ignited and burned for approximately 6 minutes, putting the satellite into an initial parking orbit.

The vehicle coasted for approximately 30 minutes, and then the Centaur was re-ignited for a second firing of 9 minutes, putting the spacecraft on an Earth escape trajectory.

Prior to separation the Centaur stage used onboard reaction engines to spin Juno up to 1.4 RPM. About 54 minutes after launch, the spacecraft separated from the Centaur and began to extend its solar panels. Following the full deployment and locking of the solar panels, Juno's batteries began to recharge. Successful deployment of the solar panels reduced Juno's spin rate by two-thirds. The probe is spun to ensure stability during the voyage and so that all instruments on the probe are able to observe Jupiter.

The voyage to Jupiter will take five years, which will include an Earth flyby in October 2013.