API VERSION: 1.2
API SOURCE: NASA/JPL Horizons API

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 Revised: Sep 01, 2026          Juno Spacecraft  / (Sun, Jupiter)           -61 
                     http://www.nasa.gov/mission_pages/juno/main/index.html
                             http://missionjuno.swri.edu/#/mission
 
 NOTE: Post-launch trajectory begins at Centaur separation.

 2016-Oct-24: A slow-responding helium check-valve issue is being analyzed, 
  resulting in delay of the main-engine burn to reduce orbit period from 53.4 
  to 14 days. The next opportunity for the burn is December 11, 2016.

 BACKGROUND:
 The Juno spacecraft (New Frontiers mission-class) will investigate Jupiter's 
 origins, interior structure, deep atmosphere and magnetosphere, from a highly 
 elliptical polar orbit with a close perijove (PJ=1.06 Jupiter-radii, AJ= 39 
 Jupiter-radii), using a suite of seven science instruments.

 The Juno spacecraft launched aboard an Atlas V-551 rocket from Cape Canaveral, 
 Fla., on Aug. 2011 at 16:25 UTC. It reached Jupiter in July 2016.  
 
 The spacecraft will orbit Jupiter 76 times during its mission (now extended
 into 2025 from its original pre-launch 19-month, 34-orbit plan), coming within
 3,100 miles (5,000 kilometers) of the planet's cloud tops.

 MAJOR EVENTS 
  Launch        : Aug 5,  2011 16:25 UTC 
  Separation    : Aug 5,  2011 17:24:56.12  UTC
  DSM-1         : Aug 30, 2012 22:29        UTC (344.95 m/s)
  DSM-2         : Sep 3,  2012 22:29        UTC (387.77 m/s)
  Shadow entry  : Oct 9,  2013 19:19:36     UTC (alt.= 7069 km, umbral)
  Earth Flyby   : Oct 9,  2013 19:21:25     UTC (alt.= 558.848) 
                   (lat=-34.170 deg,E.long= 34.008 deg
  Shadow exit   : Oct 9,  2013 19:39:01     UTC (alt.= 14896 km, umbral)
  Arrive Jupiter: Jul 5,  2016 02:30 UTC    (JOI to 53.5-day capture orbit, 
                                             delta-v= 541.7 m/s)
  Period Reduction Maneuver:
                  Oct 19, 2016 (CANCELLED)  (Target 14-day orbit period,
                                             delta-v= 395.2 m/s)
  Ganymede flyby: Jun 07, 2021 (PJ34)       (1038 km from surface, per. 53->43 d) 
  Europa flyby  : Sep 29, 2022 (PJ45)       Period from 43->38 days
  Io flybys     : Dec 30, 2023 (PJ57)
                  Feb  3, 2024 (PJ58)       Period reduced to 33 days
  End of mission: Sep   , 2025 (PJ76)       Jupiter impact, 700 km below
                                             1-bar atmospheric pressure level)

 SPACECRAFT PHYSICAL  CHARACTERISTICS:
  * Solar-powered, spin-stablized spacecraft 
  * 1 rpm in interplanetary cruise, 2 rpm in Jupiter orbit
  * Three 2x9 m solar panels equally spaced around hexagonal bus (20 m span)
  * High-gain antenna

 INSTRUMENTS: Juno's scientific payload includes:
  * A gravity/radio science system
  * A six-wavelength microwave radiometer for atmospheric sounding 
     and composition
  * A vector magnetometer
  * Plasma and energetic particle detectors
  * A radio/plasma wave experiment
  * An ultraviolet imager/spectrometer
  * An infrared imager/spectrometer

 PROPULSION:
  * Bipropellant engine: Leros 1B, thrust= 635 N,  Isp= 316.2 s min.
  * RCS thrusters
  * Orbit trim maneuvers (OTMs) occur on each orbit at perijove +4 hrs, 
     beginning at PJ3. Target desired longitude at descending node after 
     perijove.
  * Total delta-V budget: 2107 m/s (~1852 m/s on bi-prop; remainder on RCS)

 SPACECRAFT TRAJECTORY (from JPL navigation team)
   The trajectory after 2026-Aug-26 is a planning prediction.

   Trajectory name                         Start (TDB)         Stop (TDB)
   ------------------------------        -----------------   -----------------
   spk_rec_110805_*_260824               2011-Aug-05 17:19   2026-Aug-24 23:03 
   juno_pred_orbit                       2026-Aug-24 23:03   2026-Nov-16 14:51
   spk_ref_251119_281001_260129          2026-Nov-16 14:51   2028-Sep-30 23:55
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