Preplanned events leading up to the orbital insertion engine burn included changing the spacecraft’s attitude to point the main engine in the desired direction and then increasing the spacecraft’s rotation rate from 2 to 5 revolutions per minute (RPM) to help stabilize it.
The burn of Juno’s 645-Newton Leros-1b main engine began on time at 8:18 p.m. PDT (11:18 p.m. EDT), decreasing the spacecraft’s velocity by 1,212 miles per hour (542 meters per second) and allowing Juno to be captured in orbit around Jupiter. Soon after the burn was completed, Juno turned so that the sun’s rays could once again reach the 18,698 individual solar cells that give Juno its energy.
Over the next few months, Juno’s mission and science teams will perform final testing on the spacecraft’s subsystems, final calibration of science instruments and some science collection.
NASA has published a time-lapse video of the Galilean moons orbiting around Jupiter.
The movements of Jupiter’s four largest moons—Io, Europa, Ganymede and Callisto were captured from June 12 to 29 as Juno traveled closer and closer toward Jupiter, starting when the spacecraft was 10 million miles away until it was 3 million miles away.
The video also shows that Callisto, the outermost of the moons, is dimmer than the others, Bolton said. Scientists did not previously know this was the case and don’t know why—another question they’ll have to try to answer as Juno continues its exploration of Jupiter.