Akatsuki (spacecraft) significant event orbit insertion
Orbit insertion
After performing the last of a series of four trajectory correction maneuvers between 17 July and 11 September 2015, the probe was established on a trajectory to fly past Venus on 7 December 2015, when Akatsuki would make a maneuver to enter Venus orbit after a 20-minute burn with four thrusters that were not rated for such a hefty propulsive maneuver.  Instead of taking about 30 hours to complete an orbit around Venus—as was originally planned—the new orbit targeted would place Akatsuki in a nine-day orbit after an adjustment in March 2016.After JAXA engineers measured and calculated its orbit following the 7 December orbital insertion, JAXA announced on 9 December that Akatsuki had successfully entered the intended elliptical orbit, as far as 440,000 km (270,000 mi) from Venus, and as close as 400 km (250 mi) from Venus's surface with an orbital period of 13 days and 14 hours.A follow-up thruster burn on 26 March 2016 lowered Akatsuki's apoapsis to about 370,000 km (230,000 mi), periapsis altitude periodically changing from 1,000 to 10,000 kilometres (620 to 6,210 mi), and shortened its orbital period from 13 to about 10 days.