# How to attain an equatorial orbital inclination from a non-equatorial launch site?

The orbital inclination of a satellite is limited to inclinations roughly equal or greater than the latitude of the launch site, unless additional energy is expended for an orbital plane change.

In practice, what strategies are used to place satellites in equatorial LEO from a non-equatorial launch site? Is this done during orbital insertion, or at the orbital node? Are orbits temporarily raised to a higher apogee to reduce delta-v?

In practice, what strategies are used to place a satellites in geostationary orbit from a non-equatorial launch site?

• I always do a burn for an inclination change at an ascending or descending node when orbiting Kerbin :) Commented Apr 6, 2022 at 9:58

Changing the orbital inclination of an orbit is very energy intensive. But the people making that stuff happen have a few tricks up their sleeve to reduce the amount of energy (Δv to be precise) needed. It's a tradeoff between time and energy.

So the most obvious one is: Choose a launch site at the equator (or as close as possible). That's one of the benefits of systems like Virgin Orbit or stratolaunch because the plane can basically fly everywhere in the atmosphere. So they can launch directly at the equator (at least theoretically).

Another way to save propellant is to use a highly eccentric orbit with the apoapsis over the equator and do your correction burns at the highest point in the orbit (where you move the slowest).

If there are "tricks" to use the gravity of the moon and the sun to change your orbit towards an equatorial orbit "for free" (basically like sun-synchronous orbits the 98° inclination) I don't know. Maybe people with more knowledge about orbital mechanics can chime in here.

For GEO, Satellites are normally launched into a parking orbit with an apogee up at (or near) GEO and a much lower perigee. Most of the corrections are done in this mode before perigee is increased to a circular orbit as well.

• Then there's the one which isn't practically used - because it's a bit more expensive than the rest, and less convenient - but not by a very big margin - to use Moon gravity assist directly (a really close fly-by of the Moon) to change the inclination and raise periapsis. Then at the new periapsis, GEO altitude, you drop the apoapsis from the Moon orbit altitude to circularize.
– SF.
Commented Apr 6, 2022 at 8:22