Launch Azimuth

Launch azimuth is the initial heading of ascent, measured clockwise from north, and it is where geography writes itself into orbital mechanics. A rocket departing due east (090°) enters an orbit whose inclination equals the launch site's latitude — the minimum reachable without manoeuvring — while collecting Earth's rotational velocity as a gift: about 465 m/s at the equator, ~410 m/s from the latitude of the Cape, shrinking toward the poles. Steeper azimuths raise inclination; a due-south or due-north departure yields a polar orbit with no rotational bonus at all, and retrograde headings actually fight the spin. Azimuth is also bounded by safety: ascent corridors must overfly ocean or empty land, so each site publishes allowed azimuth ranges — the Cape's eastern fan for low-to-medium inclinations, Vandenberg's southern corridor for polar and Sun-synchronous work — and missions needing headings outside the fan fly a dog-leg, steering mid-ascent at a performance price. The rule that a site cannot launch *below* its own latitude's inclination is why equatorial pads are prized for GEO and why plane targets shape the entire launch manifest.