August 22, 2019

Timeline of Juno’s historic arrival at Jupiter


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NASA’s Juno spacecraft must complete a carefully-planned sequence of events as it closes in on Jupiter for a make-or-break orbit insertion burn July 4.

The timeline posted below shows the schedule of major events in the weeks ahead of Juno’s arrival at Jupiter, plus the minute-by-minute sequence of steps planned for July 4.

Times below are listed in “Earth Receive Time” and Eastern Daylight Time (GMT-4) as confirmation of the Jupiter Orbit Insertion (JOI) events arrives on Earth. The one-way light travel time from Jupiter to Earth is approximately 48 minutes.



June 20................Juno's main engine cover opened
June 27................Warm-up of Juno's helium pressurant tank
June 28................Pressurization of Juno's propulsion system
June 29 at 8:47 p.m....Juno's science instruments switched off
June 30................Final command sequence uplinked to Juno
July 4 at 9:13 p.m.....Status tones start
July 4 at 9:16 p.m.....Start initial precession to JOI attitude
July 4 at 9:37 p.m.....End initial precession to JOI attitude
July 4 at 10:28 p.m....Start fast precession to JOI attitude
July 4 at 10:41 p.m....Switch to toroidal low-gain antenna
July 4 at 10:45 p.m....Begin nutation damping
July 4 at 10:50 p.m....Start final transition to JOI attitude
July 4 at 10:53 p.m....Juno in JOI attitude
July 4 at 10:56 p.m....Spin up from 2 to 5 rpm
July 4 at 11:01 p.m....Juno spinning at 5 rpm
July 4 at 11:18 p.m....Start JOI burn
July 4 at 11:53 p.m....End JOI burn
July 4 at 11:55 p.m....Begin spinning down from 5 to 2 rpm
July 5 at 12:00 a.m....Juno spinning at 2 rpm
July 5 at 12:07 a.m....Start precession from JOI to solar-pointing attitude
July 5 at 12:11 a.m....Switch to medium-gain antenna; end status tones
July 5 at 12:16 a.m....End precession to solar-pointing attitude
July 5 at 12:36 a.m....Ground begins receiving detailed telemetry from Juno
July 5.................Replay of high data-rate telemetry
July 6.................Begin switch-on of Juno science payloads
July 13................Post-JOI trajectory course correction (if necessary)
Aug. 27................First perijove (with science instruments activated)
Oct. 19................Period reduction maneuver (from 53.5-day to 14-day orbit)
Feb. 20, 2018..........Nominal end of mission

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Follow Stephen Clark on Twitter: @StephenClark1.


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