# How to know when JPL Horizons is updated with new Juno spacecraft trajectory?

I "watched" Juno's flyby of Jupiter using the simulation in the NASA's Eyes app on my laptop, and later saw the good news in this tweet. Now I want to do a "flyby in Python".

Using the setup (shown below) in the Horizons web interface, I can easily download the state vectors of the Juno Spacecraft and Jupiter itself and subtract. This is predicted data of course, not real-time telemetry.

The header in the data file for the Juno spacecraft seems to suggest that the flyby is covered by the most recent calculation, the last entry in the list entitled ref_160226_180221_160226_V0.1. Everything after April 18, 2016 is predicted.

If I would like to see an updated trajectory - which includes measurements taken after this flyby, should I just keep checking back here, or is there somewhere else I can look to see at least notification that a new calculation has been done that is based on more recent data?

 SPACECRAFT TRAJECTORY:
From JPL navigation team. Predicts after 2016-Apr-18.0.

Trajectory name                    Start (CT)          Stop (CT)
------------------------------   -----------------   -----------------
rec_110805_111026_120302         2011-Aug-05 17:19   2011 OCT 26 00:00
rec_111026_120308_120726         2011 OCT 26 00:00   2012 MAR 08 12:00
rec_120308_120825_121109         2012 MAR 08 12:00   2012 AUG 25 00:00
rec_120825_130515_130708         2012 AUG 25 00:00   2013 MAY 15 00:00
rec_130515_131005_131031         2013 MAY 15 00:00   2013 OCT 05 12:00
rec_131005_131014_131101_reco    2013 OCT 05 12:00   2013 OCT 14 00:01
rec_131014_131114_140222         2013 OCT 14 00:01   2013 NOV 14 06:00
ref_131114_171017_140311_V0.2    2013 NOV 14 06:00   2015 MAR 26 00:00
ref_150326_180221_150326_V0.1    2015 MAR 26 00:00   2016 FEB 26 00:01
ref_160226_180221_160226_V0.1    2016 FEB 26 00:00   2018 FEB 21 11:40


• If you can figure out who runs that data, you can probably shoot them an email. The people who run the Eyes app are pretty good about replying. – Phiteros Aug 29 '16 at 20:53

Well one way is to just keep checking manually, until you find that something has changed. If there is a better way please post an answer!

On August 31st, a few days after the flyby, a new solution was generated. If you look for the <- HERE! markers you can see where older and newer calculations are spliced together.

The flyby in the new solution is the same distance from Jupiter as the old one, and only about 30 seconds earlier:

above: Plot of the distance from the Juno spacecraft to the center of Jupiter minus an equatorial radius of 71492 km. Solid line is the newer solution, dashed line is the older solution.

## OLD:

 SPACECRAFT TRAJECTORY:
From JPL navigation team. Predicts after 2016-Apr-18.0.   <- HERE!

Trajectory name                    Start (CT)          Stop (CT)
------------------------------   -----------------   -----------------
rec_110805_111026_120302         2011-Aug-05 17:19   2011 OCT 26 00:00
rec_111026_120308_120726         2011 OCT 26 00:00   2012 MAR 08 12:00
rec_120308_120825_121109         2012 MAR 08 12:00   2012 AUG 25 00:00
rec_120825_130515_130708         2012 AUG 25 00:00   2013 MAY 15 00:00
rec_130515_131005_131031         2013 MAY 15 00:00   2013 OCT 05 12:00
rec_131005_131014_131101_reco    2013 OCT 05 12:00   2013 OCT 14 00:01
rec_131014_131114_140222         2013 OCT 14 00:01   2013 NOV 14 06:00
ref_131114_171017_140311_V0.2    2013 NOV 14 06:00   2015 MAR 26 00:00
ref_150326_180221_150326_V0.1    2015 MAR 26 00:00   2016 FEB 26 00:01

ref_160226_180221_160226_V0.1    2016 FEB 26 00:00   2018 FEB 21 11:40   <- HERE!


SPACECRAFT TRAJECTORY:
From JPL navigation team. Predicts after 2016-Aug-22.   <- HERE!

Trajectory name                       Start (TDB)         Stop (TDB)
------------------------------     -----------------   -----------------
rec_110805_111026_120302           2011-Aug-05 17:19   2011 OCT 26 00:00
rec_111026_120308_120726           2011 OCT 26 00:00   2012 MAR 08 12:00
rec_120308_120825_121109           2012 MAR 08 12:00   2012 AUG 25 00:00
rec_120825_130515_130708           2012 AUG 25 00:00   2013 MAY 15 00:00
rec_130515_131005_131031           2013 MAY 15 00:00   2013 OCT 05 12:00
rec_131005_131014_131101_reco      2013 OCT 05 12:00   2013 OCT 14 00:01
rec_131014_131114_140222           2013 OCT 14 00:01   2013 NOV 14 06:00
ref_131114_171017_140311_V0.2      2013 NOV 14 06:00   2015 MAR 26 00:00
ref_150326_180221_150326_V0.1      2015 MAR 26 00:00   2016 FEB 26 00:01

ref_160226_180221_160226_V0.1      2016 FEB 26 00:00   2016 APR 13 18:00   <- HERE!
pre_160413_161016_160818_pj01_V0.1 2016 APR 13 18:00   2016 OCT 16 23:00
ref_160226_180221_160226_V0.5      2016 OCT 16 23:00   2018 FEB 21 11:40