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I've just noticed this post. A couple of factoids that might be relevant. Orbiter uses the VSOP87 ephemeris for planetary positions, not a DEXXX ephemeris from JPL. The VSOP87 ephemeris uses the time coordinate known as TT (Terrestrial Time), which is a modern continuation of the former...

Just to add a little to the above discussion: Orbiter 2016 uses the VSOP87 ephemeris, which is a planetary theory developed by the Bureau des Longitudes in Paris. It was used for computing the positions of the planets (Mercury through Neptune) with high accuracy. As you might guess, it was...

In this post, I'll revisit an old topic: finding the points of intersection of two co-planar orbits. This question was asked in a much earlier post [Calculating intersection of two Orbits]. However, the solution provided in that post, although functional, was not aesthetically appealing and...

No problem. If I had had to guess from your original post, I would have been inclined to think that nuances of inverse trig functions and using Kepler's equation to solve for the time-of-flight would have been the culprits - they certainly have caused me a lot of angst over the years. In...

OK, see if the attached file is any use. I haven't rigorously checked for errors, but I've done a couple of spot checks and it seems to work.

Ok, not entirely clear on what you want - but it seems to be the following: let's suppose that you start in a circular (outer) orbit and at some point execute a retrograde burn (tangent to your orbit) at some arbitrary point on that orbit and assuming that the transfer orbit intersects with...

Hi, ajubb - think I re-posted the missing file in post #13 above. If this doesn't work, let me know.

Hi, Biagio - wrt to the missing Excel file, I've attached two Excel files as .zip files. These are variations of the optimisation scheme intended for an 'outer' and 'inner' transfer (if I recall correctly). Both should work - but you will have to experiment to see which of the two meets your...

Here are a couple of useful equations: \begin{aligned} v_a &= \sqrt{\frac{r_p}{r_a}\,\frac{2\,\mu}{r_a + r_p}} \\ v_p &= \sqrt{\frac{r_a}{r_p}\,\frac{2\,\mu}{r_a + r_p}} \\ \end{aligned} Now, let’s suppose that one executes a prograde burn at apoapsis of magnitude \delta V; and let’s suppose...

Yes, that’s about the size of it.

Sigh Enough of this, methinks. Over the years, I’ve read too many differing views of what Einstein actually thought, what Minkowski actually proved, and assorted claims of resolution of the Twin Paradox. You clearly have your views of the universal validity of the Clock Hypothesis. I have my...

Sure - enjoy.

The use of special relativity to address question relating to accelerating reference frames relies on the Clock Hypothesis - namely that “when a clock is accelerated the effects of the motion on the rate of the clock is no more that associated with its instantaneous velocity - the acceleration...

My suggestion remains to treat this subject with a degree of caution. In the realm of special relativity, one needs to consider the problematic issue of clock synchronisation. In the specific theory, Einstein proposed an explicit synchronisation procedure for clocks in different inertial...

I would be a little careful when combining accelerations with special relativity. Special relativity is built around the notion of inertial (i.e., non-accelerating) reference frames and it is an ongoing topic of debate as to whether (or how) accelerations should be accommodated within the...

Hi, Rock_Doc I think the attached is the missing file. Let me know if you have any issues. Regards Mont B

What sort of transfer orbits do you want to calculate?

Pantanplan: OK, I’ve located the deleted dropbox file. I’ll send to you via PM. P.S. If in the future any one else needs this file, let me know and I will send to you.

Pantanplan: sorry for the slow response - but, of late, I only check in here at O-F once a month or so. I will have a search through my files and see if I can resurrect the spreadsheet.

The short answer is: yes. However, a bunch of more practical issues (associated with macro-economic concerns and, of course, COVID-19) have stolen much of my attention for the last year or so. At some point, I'm sure, I'll find the time to focus on all things Lissajous once again. Regards