Resources employed

Although the missions of the Range Safety and Environment Department mostly involve people, the nature of its work also requires technical resources (software and equipment) and special arrangements for protecting life, property and the environment. Here are some of the resources available to it.

Special arrangements – Flight Safety during preparation campaigns

Risk control for launcher flight involves two distinct zones: ‘near field’ and ‘far field’ zones.

Near field :

This involves studying the trajectories when the launcher flies over coastal regions. For this zone, computer simulations are performed to determine minimum safety limits, using :

• software which calculates possible departures from the launcher's planned trajectory so as to determine minimum safety limits of safety intervention beyond which a launcher considered dangerous must be destroyed.
• an explosion simulator to determine the impact area of fragments and toxic elements of Ariane.

Far field :

This involves studying the trajectories after the launcher leaves French Guiana, to estimate the possible risks of injury or death in the event of unplanned engine shutdown. These risks must be less than 1 in 10 million (10-7). Since the launcher is not placed in orbit, there is a risk that it will fall back to Earth unexpectedly. For the far field zone the Flight Safety specialists calculate the probability of injury or death on the ground in the event of launch vehicle failure.

Flight Safety arrangements on Launch Day (D-0)

These include :

• A tracking and location system which displays the trajectory, with 3 radars giving the real-time position and speed of the launcher during flight. Trajectory predictions are calculated once for second of flight.
• A telemetry system receives, records and processes all information transmitted by the launcher (on its attitude, engines etc.).
• Weather forecasting : a radio sounding system analyses wind direction and strength. Flight Safety personnel use these data to calculate where debris might fall back to Earth after a possible explosion of the launch vehicle. The calculated fallback zones are among the factors the Director of CNES/CSG takes into consideration when decided whether or not to proceed with the launch. All through the final countdown the team provides wind forecasts for the Kourou region.
• A remote-controlled autodestruct system is available to neutralise the launcher at any time if it should deviate from its planned flight corridor.

 Computers calculate the fallback of the Main Cryogenic Stage (EPC) providing the Safety team with the position and speed of the EPC within five minutes of separation.

Technical resources at the Payload Preparation Complex (EPCU)

One console is reserved for satellite fuelling operations.

Technical resources at the Ariane Launch Complex (ELA)

All potentially dangerous circuits are directed through a console used to detect human errors. This relies on 2 principal monitoring systems :

• The Housekeeping Control and Command Centre (CCS) which oversees the detection of gas, fires or toxic gases as well as fire control, sirens and the evacuation of facilities.
• The Operational Control and Command Centre (CCO) which can control valves and circuits that could be at risk during operations (pyrotechnics, electrics, fluids, flooding and spraying).

Specialised equipment

The teams also have other specialised tools to help them take appropriate measures :

• Accident simulation software for defining and plotting danger zones for the consequences of any theoretical accident. The Range Safety Department uses these plotted perimeters to establish contingency scenarios.
• A system for measuring the rate at which toxic fallback can reach a given site from the atmosphere.
• The convoy network for keeping track of dangerous substances during transport.

All these resources enable real-time evaluation of launcher behaviour and the possibility of neutralising it should it become dangerous.

The Range Safety Coordination Office (BCS)

This office coordinates risk-related activities and ensures that legal and Range Safety requirements are observed for all inter-site activities, such as unloading dangerous substances at Pariacabo harbour and transporting them to the Centre. This requires familiarity with all the sites, facilities, operations and their related risks and a capability for swift response to deal with an accident. Before authorising any operation, the Range Safety Coordination Office uses accident simulation software to highlight the danger zones. During launch campaigns, the office sends out safety recommendations to the various units on the base right up until launch time so that they 'comb' their zones (to ensure removal of all personnel) and check safety and protection equipment, etc.