# Orbit ephemeris or visualization for the BepiColombo mission?

Where is it possible to see the progress of the BepiColombo mission in terms of ephemeris and or graphical visualisation?

I should add, I've checked JPL Horizons, though its not clear how to specify a newly launched satellite.

• Most NASA and ESA missions with NASA involvement can be found in NASA. Even simulated trajectories for not-yet-launched spacecraft can be found there for planning purposes. I was sad to see that BepiColombo & MIO aren't there though. Here are plots for the future JWST 1, 2 and yet only words for BepiColombo 3, 4 If you like Scott Manley there's this youtu.be/1Sj9cjwFhQY – uhoh Oct 25 '18 at 11:57
• There's also a qualitative infographic here: planetary.org/multimedia/space-images/charts/… – uhoh Oct 25 '18 at 13:07
• Thanks for the links, I've looked through them all. When you say "found in NASA" do you mean the JPL Horizons, i.e. that is the end of the road for the moment? The ESA link, Getting to Mercury is really helpful, so it looks like the Electric Propulsion system gets used for the first proper thrust arc quite soon, or at least within six months. – Puffin Oct 27 '18 at 10:48
• ya I'd meant to type "Horizons" not "NASA". But that doesn't mean they can't be found other places, so to the "i.e." I think "not necessarily". I don't know much about the trajectory or planned propulsive maneuvers really. – uhoh Oct 27 '18 at 10:59

I had written in comments, in regard to finding out when the electric propulsion would be started, that this could be determined from Horizons (temporarily forgetting that it's not there):

A quick way to check would be to get the position and velocity from Horizons relative to the Sun rather than the solar system barycenter, then calculate the specific energy $$\frac{1}{2}v^2 - \mu/r$$ and see if it's dropping. That will show what they modeled for the electric propulsion in the simulation.

Which made me wonder further why it's not there. Then an answer "dawned" on me. (pardon the pun) Because it's not a NASA mission, NASA would not have first-hand access to the propulsion envelope modeled or implemented, so it can not reliably second-guess the trajectory, nor would it want to have to update it each time ESA made a change in timing.

You wouldn't want to have a random trajectory floating around, appearing official and precise, but outdated.

• Why couldn't NASA simply ask the ESA for that information? – Sean Oct 27 '18 at 20:06
• Yes, good idea, I had been wondering what my next steps would be should I actually get some trajectory information. I have looked around ESA links, the one you mentioned earlier was the best yet, though its still surprisingly vague as to the details. Its as if they really don't think people are interested, which is odd given who's paying for it all! – Puffin Oct 27 '18 at 22:17
• @Sean 1) that would work if the information were something simple and standard, but a space mission trajectory is complex, and ESA may not even be using the same JPL ephemerides for the solar system bodies. Horizons is not a place to just "post" orbits (thought that may happen sometimes), it's an integrated system. 2) keeping up with trajectory changes in the ESA mission is hard to do internally within a space agency, but between space agencies would be a full time job and everybody is already busy 3) it's never good to have multiple, independent sources of the same information. – uhoh Oct 28 '18 at 0:16
• @Puffin NASA takes their responsibility to the lay public as well as the science public extremely seriously. Want the position and speed of a spacecraft or rover on your birthday, you can get it online! An image that a certain spacecraft or rover took on a certain day, download now! Use it (non-commercially) too! NASA's public outreach is not "normal" in the world, nor "normal" within the US government. It's just one of those positive things in the world makes the negative stuff more bearable. I'm not at all associated with NASA or the industry, just a big fan for the last half century. – uhoh Oct 28 '18 at 0:25
• As for BepiColombo's orbit, with a published series flyby dates and times, and the JPL ephemerides, it should be possible to back-calculate and reconstruct a reasonable model of the whole trajectory, making some assumptions of the ion engine usage. Still it seems it would be easy for them to release at least something. – uhoh Oct 28 '18 at 0:28