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I have seen nearly all orbital 2D projections done like a sine wave. However, when I watch a launch from say, Cape Canaveral, it always "appears" that they are launching due east rather than such a steep inclination as what a sine wave projection would imply. So, if they are/were launching due east with relation to the equatorial plane, my question then is; "Wouldn't the orbital flight path then always be a linear path rather than a sine wave?" I cannot understand how nearly everything launched would have a sinusoidal projection.

Skittles
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  • Also relevant: https://space.stackexchange.com/questions/40842/why-does-launching-east-result-in-an-orbital-inclination-equal-to-the-latitude-o – Organic Marble Feb 06 '24 at 02:46
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    Launching "due east" from Canaveral puts a satellite into an orbit inclined about 28º as described in this QA, but the ISS and everything that launches to rendezvous with it are inclined even further, to about 51º. – Russell Borogove Feb 06 '24 at 06:48
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    @uhoh "Due east" launches weren't unknown for shuttle pre-ISS; they still result in a sinusoidal ground track because the center of the Earth must lie in the orbital plane; the vehicle can't circle the Earth along the 28th parallel. No idea how common such launches are now. – Organic Marble Feb 06 '24 at 13:27
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    @OrganicMarble oh, duh, my bad. It's those darned cosmic rays again. – uhoh Feb 06 '24 at 15:10
  • Thanks folks. Always wondered about this, because I always figured they would prefer a due east, 0 deg inclination. Not sure why they don't, but makes sense. – Skittles Feb 10 '24 at 02:32
  • @Skittles In general they would prefer a due east 0 degree inclination orbit but to get that the launch site would have to be on the equator; Canaveral is 28º north so an initial orbit will be a great circle inclined at 28º to the equator. To get to the ISS or into an equatorial orbit the spacecraft needs to change inclination by firing the engine. The ESA mostly launches from Kourou in French Guiana which is at 5º north and requires less of an inclination change to get into an equatorial orbit. – Dave Gremlin Feb 14 '24 at 18:56

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