Celestia Forums

Hey All

My first "addon" for some time, this is more of an experiment really, that could even have a place in the Physics & Astronomy forum...

I recently investigated Horizons' "user-specified small bodies" option (press ; at the telnet prompt) and found it to be much more straightforward than i thought it would be! Just as a test, I took the very last coords for Ulysses (Dec. 31st 2005, at 21:00) and used them as a base for the -future- ulysses trajectory.

(I used MA, A instead of TP, QR also because the latter seemed to produce very strange results the first time...)

So heres what the trajectory looks like between 2003-jan-1st and 2199 dec-31st (looking from below the sun):


Yup, you guessed it... Another -predicted- close flyby of Jupiter in 2094 sends it on a much less eccentric orbit, slightly larger than jupiter's own, and inclined about 110 degrees from the ecliptic!

This is something like how a satellite gets put into a geostationary orbit too, except that in that case a rocket motor fires at apogee, instead of a handy gravity boost from Jupiter...

You can download this xyz from here http://homepage.eircom.net/~jackcelesti ... future.zip
(Haven't got the time to change my site at the mo...)

Hope you found this interesting!!!

Hm... 42 views so far & no replies yet... I thought that people would be very interested in Horizons' ability to predict the trajectories of user-inputted bodies...!

Anyone have any comments, or tried this this themselves in Horizons?!!

PS. Its in 2098 that the big gravity boost happens not 2094...

At 2199 we could well be offering tourist travels to see 'Old Relics from the Ancient Space Times' the same way we visit cavern paintings...


Good work!

That's very cool Jack . . . I didn't know Horizons would handle custom objects. Do you know what solar system bodies are accounted for when the trajectory is integrated over time?

--Chris

JackHiggins wrote:Hm... 42 views so far & no replies yet... I thought that people would be very interested in Horizons' ability to predict the trajectories of user-inputted bodies...! :?

Anyone have any comments, or tried this this themselves in Horizons?!!

PS. Its in 2098 that the big gravity boost happens not 2094...

Very interesting. I'll try myself. Thanks

chris wrote:That's very cool Jack . . . I didn't know Horizons would handle custom objects. Do you know what solar system bodies are accounted for when the trajectory is integrated over time?

As far as I can tell, all "major bodies" gravitational effects are taken into account, so that means all the planets & moons, ceres, pallas & vesta. (those 3 asteroids are labelled as "minor perturbers" though)
The full horizons documentation is here:
http://ssd.jpl.nasa.gov/horizons_doc.html

I remember some people wanted to try this out themselves before but weren't sure what to do- the Horizons system was updated recently so maybe they changed the way you input your own elements....