Here is a screen shot from NY2O of the ground track from GSAT-6A (43241, 2018-027A). What kind of orbit can make this wave shaped ground track?

enter image description here

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    $\begingroup$ Quite similar to Mars's retrograde motion. $\endgroup$ – ugoren May 14 '18 at 12:27
  • $\begingroup$ I want to ask the question "is it possible to get a 'straight line' orbit from this elliptical orbit" but have no idea how to begin phrasing it. $\endgroup$ – Magic Octopus Urn Jun 21 '18 at 16:28
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    $\begingroup$ @MagicOctopusUrn if the orbital plane is also the Earth's equatorial plane, I think pretty-much yes. If it's not, I think pretty-much no, but why not ask? And in addition to a 'straight line' you could ask about any great circle orbit or an orbit parallel to lines of longitude or lines of latitude. Ask about all of them, it should be answerable in one post. $\endgroup$ – uhoh Jun 21 '18 at 16:53
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    $\begingroup$ @uhoh that would've been my guess; I think I'll keep my vague question answered by a vague comment :P. Thanks again good sir! $\endgroup$ – Magic Octopus Urn Jun 21 '18 at 17:59

An elliptical one. The Wikipedia page you link gives a signfiicantly different apogee and perigee and a period of 20.8 hours. So, on average, it moves West to East a bit faster than the Earth does, but at apogee it's moving more slowly and the Earth overtakes it a bit (which are the "S-bends" in the track). It swings a little North of the equatorial plane while approaching the Earth, and a bit South while receding. At the moment of the above screenshot it is close to perigee.

Each full cycle of the wave pattern is an orbit, so after roughly six orbits (120 hours) when the Earth has turned five times beneath it, it will get back to the same longitude. This fits with the apparent size of the wave pattern on the map, which is credibly about 4 time zones.

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    $\begingroup$ Wikipedia says 3.29 degrees. $\endgroup$ – Steve Linton May 13 '18 at 9:20
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    $\begingroup$ The Earth turns west to east! So that's the descending node you've found. $\endgroup$ – Steve Linton May 13 '18 at 10:24
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    $\begingroup$ Ha! Indeed it does. I think that it used to turn the other way, but I guess they changed it in the early 1960's to make launching from Florida easier. ;-) $\endgroup$ – uhoh May 13 '18 at 10:26
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    $\begingroup$ Terrific, concise answer. If I could, I'd give, 2, possibly 2.7 upvotes. $\endgroup$ – Russell Borogove May 13 '18 at 15:18
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    $\begingroup$ @ChrisR See the wikipedia page linked in the question -- they lost contact before the final orbit-lifting burn. $\endgroup$ – Steve Linton May 14 '18 at 7:37

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