# Mathematical description of the flight trajectory parameters of voyager 1

I would like to run in some simulation software an end-to-end simulation replicating the flight of voyager 1. I am somewhat conversant with GMAT that I think would have this capability or perhaps there is something better. I would need the initial velocities and orientation and all of the thrust maneuvers (propagators) along the way as to magnitude and direction. I would like my "voyageur" to proceed based upon solution of gravitational force equations rather than just proceed along a prescribed path.

I would like to run it at 50x time so that entire journey would take 6 months or so but I could look and see where it was every few days or so. I am not sure that GMAT has all the gravitational sources (bodies) needed so I would likely need to add to the GMAT library of bodies.

I am unaware of any such detailed log of firings and orientation vectoring and hope this exists.

Just a fun project. Anyone with any approaches?

tom kosvic

• does it have to be an actual home-grown simulation? This will be incredibly difficult because of he nature of the trajectory having many close planetary flybys where tiny errors will be dramatically amplified by subsequent flybys, and because there were many propulsive trajectory correction maneuvers that would have to be correctly included as well. The positions of all the planets, especially during the flybys would also have to be included.
– uhoh
Sep 22, 2022 at 19:26
• The reason I ask is that all of this has already been done with great effort and can be accessed via JPL's Horizons You can download the entire trajectory as well as the positions of the planets for the entire mission timeline then "play it back" at 50x.
– uhoh
Sep 22, 2022 at 19:26
• I suppose you could get thrust data from JPL, but you need more than that. The Voyager 1 (and 2) trajectories on Horizons were updated a few weeks ago, with various improvements to account for things like "Mismodelling of solar pressure" & "Thermal radiation from RTG power sources". See ssd.jpl.nasa.gov/api/… Sep 23, 2022 at 0:11
• @uhoh, thanks for ref. Had never spent any time with Horizons but easily generated a "coordinates" file for 1977 onward. Now need to find a means of viewing the file; likely a top-down orbital (orrery) view would be good. Was hoping to actually compute this info but I will look at a display of the data for a while. Perhaps computing this from 1st principles is a bit too ambitious. As you indicated, I'd have to incorporate items like solar pressure which would be quite ambitious. thanks, tom kosvic Sep 24, 2022 at 16:01
• @tckosvic there are several questions and answers here about extracting data from Horizons to Python directly. Have a look around and if you don't find enough, you can always post a follow-up question as well.
– uhoh
Sep 25, 2022 at 0:04