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

*******************************************************************************
 Revised: Aug 19, 2022   Voyager 2 Spacecraft (interplanetary) / (Sun)     -32
                        http://www.jpl.nasa.gov/missions/voyager-2/

 BACKGROUND
   See the web-page above for information on the Voyager Mission

 TIMELINE
   1977-Aug-20  Launch from Kennedy Space Center @ 14:29 UTC
   1978-Jun     Primary receiver failed, rest of mission on backup
   1979-Jul-09  Jupiter closest-approach
   1981-Aug-25  Saturn encounter
   1986-Jan-24  First Uranus encounter
   1987         Observes Supernova 1987A
   1989-Aug-25  First Neptune encounter; begins trip outside solar system
                 below ecliptic plane
   1992-Jul-17  Last transponder tracking data
   2007-Sep-05  Crosses solar system "bow shock" boundary
   2012-Aug-13  Becomes longest operating spacecraft
   2018-Nov-15  Crossed heliopause, entered interstellar space

 SPACECRAFT TRAJECTORY:
   This trajectory is composed of two merged sections:

     #1) 1977-Aug-20 to 1989-Aug-29:
          A patched conic mission-design type trajectory in which the conics 
          were constructed to approximately match specific events (such 
          satellite encounters), providing a rough accuracy. 

     #2) 1989-Aug-29 to 2100-Jan-1 
          Refit of tracking data spanning 1989-1992 (from Neptune encounter to 
          the end of two-way coherent transponder data). Produced in 2022 by 
          R. Jacobson (former Voyager navigation) using DE440 to generate a new
          solution and long-term prediction. 

   The reconstruction done in 2022 estimated:
      - Epoch state vector
      - Constant and stochastic non-gravitational accelerations 
         (to account for the activity of three-axis attitude control system)
      - Thermal radiation from RTG power sources
      - Mismodelling of solar pressure  
      - 24 impulsive maneuvers

   Note there has been no new tracking data possible since 1992. This is a
   different issue from on-board telemetry, which continued beyond that date. 
   DSS-43 (Canberra) is the only DSN site still equipped to communicate with
   Voyager 2.

   The 2022 update refit the existing old tracking data using modern approaches
   and standards to allow consistent extrapolation to 2100.

   Formal predicted geocentric pointing uncertainty on 2030-Jan-1:
     RA +/- 4.718 arcseconds, DEC +/- 3.715 arcseconds

   This uncertainty is consistent with the new solution's difference with 
   the M05016 prediction made in 1990. 
 
   Tracking data used in 2022 solution:
     Points Type       First point            Last point       residual rms
        170   F2   31-Aug-1989 12:57:30  17-Jul-1992 20:17:00  0.137 mm/s
       1098   F3   30-Aug-1989 01:13:30  30-Oct-1992 18:05:00  0.120 mm/s
         67  SRA   31-Aug-1989 12:50:01  21-Jul-1991 19:38:58  229 m
*******************************************************************************