* Astronomy

Blobrana · L

RE: Ariane 5 ECA launch

Blobrana · L

T + 2 m 19 s Jettisoning of solid boosters 64.5km 1968m/s

Blobrana · L

Lift off!

HO Ignition of the cryogenic main stage engine (EPC) ALT (km) V. rel. (m/s)
T + 7,0 s Ignition of solid boosters, The twin boosters will burn for 2 minutes, 19 seconds
T + 7,3 s Lift-off
T + 13 s End of vertical climb and beginning of pitch rotation (10 seconds duration) 0.093km 37m/s
T + 17 s Beginning of roll manoeuvre 0.334km 74m/s

Blobrana · L

T - 05,5 s Command issued for opening of cryogenic arms
T – 04 s Onboard systems take over
T – 03 s Unlocking of guidance systems to flight mode

Blobrana · L

T minus 1 minutes

Switch to onboard power mode

Blobrana · L

T minus 4 minutes

Tanks pressurised for flight

Blobrana · L

T minus 6 minutes

All systems are go

Blobrana · L

The launcher’s attitude and trajectory are totally controlled by the two onboard computers, located in the Ariane 5 vehicle equipment bay (VEB).
7.05 seconds after ignition of the main stage cryogenic engine at T-0, the two solid-propellant boosters is ignited, enabling lift-off. The launcher first climbs vertically for 6 seconds, then rotates towards the East. It maintains an attitude that ensures the axis of the launcher remains parallel to its velocity vector, in order to minimize aerodynamic loads throughout the entire atmospheric phase, until the solid boosters are jettisoned.
Once this first part of the flight is completed, the onboard computers optimise the trajectory in real time, minimizing propellant consumption to bring the launcher first to the intermediate orbit targeted at the end of the main stage propulsion phase, and then the final orbit at the end of the flight of the upper cryogenic stage.
The main stage falls back off the coast of Africa in the Atlantic Ocean (in the Gulf of Guinea).
On orbital injection, the launcher will have attained a velocity of approximately 9,322 meters/second, and will be at an altitude of about 694 kilometres.
The fairing protecting the SPACEWAY 2/TELKOM-2 spacecraft is jettisoned shortly after the boosters are jettisoned at about T+194 seconds.

Blobrana · L

T minus 10 minutes

Blobrana · L

The countdown comprises all final preparation steps for the launcher, the satellites and the launch site. If it proceeds as planned, the countdown leads to the ignition of the main stage engine, then the two boosters, for a lift-off at the targeted time, as early as possible in the satellites launch window.
The countdown culminates in a synchronized sequence, which is managed by the control station and onboard computers starting at T-7 minutes.
If an interruption in the countdown means that T-0 falls outside the launch window, then the launch will be delayed by one, two or more days, depending on the problem involved, and the solution developed.