The countdown

The countdown is the final phase of the launch campaign, during which the management teams for each function come together in the Jupiter room to coordinate launch decisions. It starts 10 hours before lift-off and ends when the satellite is placed in orbit. Throughout the countdown, a series of intermediate processes ensure maximum security.

Before launch

An initial contingent of team members arrives in the Jupiter Room at T – 10 hours. The base’s resources are mobilised as of T – 6 hr but the first operations to be coordinated from Jupiter only begin at T – 4 hours 30 min.

All operational managers run through their flight procedures and check that all resources are available. They monitor the key stages for implementing these resources and send reports on the different stages to the Director of Operations. The Director follows-up the procedures and coordinates management of the launch base and the range safety mission. Several managers assist him with this, including assistants for instrument readings, logistics and quality, operations managers and meteorology and flight safety assistants.

The Mission Manager, for his part, keeps the Director of Operations informed of the state of the launch complex and the launch vehicle and satellite systems. The Director of Operations coordinatse operations with the various other managers via a complex intercom system.

All this information acquired in real time gives the Director of Operations a complete synoptical overview of the state of all the resources used for the launch (the base, launch vehicle and satellites). This process continues until T – 22 minutes when a check is made to ensure that all systems are 'go'.

At T – 20 minutes, the weather forecasting department issues its bulletin, including an analysis of wind speed and direction, the risk of lightning, etc.

Then at T – 16 minutes, if all systems are 'go', the liquid oxygen loading procedure can commence. From the start of this sequence until T – 4 minutes, the Director of Operations can still interrupt the countdown manually if any system indicator switches to red. At T - 4 minutes, the power to stop the countdown in the event of any fault passes from the Director of Operations to the computers.
From T – 7 seconds, it is no longer possible to stop the countdown as the launch vehicle is in autonomous mode.

After the launch

The phase between liftoff and satellite positioning is called the countup. The first eight minutes after liftoff are crucial. Scientists track the launch vehicle along its trajectory thanks to radar data and remote sensing devices. If the launcher leaves its nominal trajectory or cannot reach its planned orbit, the range safety officer can decide to activate the destruct system.

The remainder of the countup covers the satellite positioning operation. Finally, a positioning report is delivered to the customers to confirm that mission objectives have been accomplished.

At this point, you can see a great change in the atmosphere of the control centre. Smiles, congratulations and handshakes all round mark the end of the long hours of stressful concentration.