* Astronomy

Flight is fine.

HO Ignition of the cryogenic main stage engine (EPC) ALT (km) V. rel. (m/s)
T + 7,0 s Ignition of solid boosters
T+ 7,3 s Lift-off
T+ 12,5 s End of vertical climb and beginning of pitch rotation
T+17 s Beginning of roll manoeuvre
T+ 2 minutes 18 s Jettisoning of solid boosters
T+ 3 minutes 08 s Jettisoning of fairing


About three and 8 seconds after lift-off from Europe's Spaceport in French Guiana, the Ariane 5 fairing protecting the satellites is ejected.
Five and a half minutes later, the main cryogenic stage (Etage à Propergol Cryogénique or EPC) separates, leaving the cargo module attached to the upper stage.
The upper stage carries the cargo module to a circular orbit, using two powered phases with its Aestus motor, separated by a 45-minute ballistic phase:
The cryogenic first stage will exhaust its propellant resources almost 10 minutes into the flight. After separation, the storable propellant upper stage will ignite to begin its lengthy 17-minute burn to finish the Ariane 5's ascent.
After EPC separation, the EPS upper stage motor, Aestus, is ignited for about eight minutes, over the Atlantic Ocean, before the ballistic trajectory, which describes half an orbit around the Earth.

Whilst passing over southeast Australia, the Ariane 5 re-ignites, a first time, for 40 seconds its EPS upper stage Aestus motor to circularize the orbit at an altitude of 565 km.

Syracuse 3A deployment is set for 29 minutes, 28 seconds after lift-off, followed about 10 minutes later by release of Galaxy 15.

Meanwhile, the EPS and the equipment bay of the Ariane 5 fulfil a last and important task. One orbit later, now over western Australia, Aestus re-ignites briefly, for a second time, causing the launcher to de-orbit safely and burn up during a precise re-entry over a predefined uninhabited South Pacific area.