The Ariane-5 Launch Facilities

J. De Dalmau

ESA Office, Guiana Space Center, Kourou, French Guiana

P. Perez

Launchers Directorate, CNES, Evry, France

Evolution of the launch complex design

To date, two launch complexes for the Ariane family of vehicles have been built within the framework of the Ariane development programme, at ESA's Guiana Space Centre in Kourou, French Guiana. The first one was used to launch Ariane-1,-2 and -3 between 1979 and 1989. The second one has been used to launch Ariane-3 and -4 since 1986 and is still being used. A third launch complex, dedicated to the launching of the new Ariane-5, is currently under construction.

The design concept behind the launch facilities has been evolving since the design of the first launch complex, based on experience gained and to improve the product's quality, availability and operational flexibility and thus reduce launch costs. The main criteria for the evolution have been:

• to increase the launch rate
• to reduce vulnerability to a launcher accident on the launch pad or at lift-off
• to optimise the operational activities
• to adapt the facilities to Ariane launch vehicle changes
• to exploit the experience acquired during previous developments.

The launch complexes, which are financed and owned by ESA, have been designed and built by the French Space Agency, CNES, on ESA's behalf. During the commercial utilisation phase, Arianespace, the European launch services operator, is responsible for the operation of the facilities that interface directly with the launcher, i.e. the launch complexes or ELAs (Ensembles de Lancement Ariane), and with the payloads, i.e. the EPCU complex (Ensemble de Preparation des Charges Utiles).

The Ariane launcher family is continuously being modified to meet commercial needs in order to stay competitive. In addition, the launch facilities have to be upgraded through new and optimised investments which represent between 10 and 15% of the development costs of the respective launch vehicles. An Ariane launch campaign in Guiana includes all operations from he arrival of elements (stages, vehicle equipment bay, fairing, spacecraft, etc.) until the launch vehicle is ready for lift-off, and ends with the actual launch and the orbiting of the spacecraft.

Launch complex No. 1 - ELA1

The design of the first launch complex, ELA1, began in 1973, soon after the Ariane programme was approved at the European Space Conference in Brussels. The main design criteria were:

• a capacity of four launches a year, which was at that time the maximum foreseeable rate
• the existing facilities in Guiana which one of ESA's fore runners, the European Launcher Development Organisation (ELDO), had built for the Europa 2 vehicle, had to be used. Those facilities in fact had only been used once, for a launch in November 1971.

That launch site was thoroughly modified and adapted to Ariane. Since all campaign operations had to be performed sequentially on the launch site itself, the number of possible launches was limited to one every two months, which was thought to be more than enough at the time.

The first Ariane launch took place from ELA1 on 24 December 1979, and the complex then remained operational until the launch of the last Ariane-3 vehicle in mid-1989. The servicing tower was dismanted in 1991.

During its life time, ELA1 provided very acceptable and competitive conditions for 25 launches, but some improvements were required:

• the launch rate was limited
• hazardous and sensitive facilities were located too close to the launch pad
• there were two main disadvantages to re-using the Europa 2 facilities: it was difficult to integrate equipment inside the umbilical mast (which holds and protects the electrical and fluid links between the launcher and the ground facilities) making maintenance more complex, and the orientation of the launcher and the mast relative to the dominant winds was not optimal, limiting the acceptable wind speed at lift-off to 9 m/s.

Launch complex No. 2 - ELA2

The design, construction and validation of the second launch complex, ELA2, were carried out between 1981 and 1985. The design was based on the following requirements:

• compatibility with the Ariane-3 and Ariane-4 family of vehicles
• a doubling of the ELA1 launch rate, narrowing the interval between launches to one month and allowing 10 launches per year
• greater operational flexibility, maximum accessibility, reduction of constraints and a general optimisation of the operations.

The required improvement in the launch rate was achieved by separating geographically the preparation area from the launch area, enabling two launch campaigns to be undertaken at the sametime. When the stages of the first ehicle have been erected, assembled and checked in the preparation area (in the first weeks of the campaign), the vehicle is rolled out on its mobile launch platform to the launch area for the remaining part of the campaign. While it is undergoing mating and check out of the payload, count down and finally, the launch, the stages of the second vehicle can be assembled in the preparation area. After the launch of the first vehicle, the launch pad is then refurbished in preparation for the second vehicle.

With this separation, the launch rate increased to one per month, thus doubling the capacity of the ELA1 at a cost that is only 30% higher. Arianespace has in fact recently shortened the minimum period between Ariane-4 launches to 18 working days (i.e. three to three and a half weeks), to cope with increasing commercial demand.

Experience gained with ELA1 was fully used in the design of ELA2:

• The launch pad was better oriented relative to the dominant winds, and the acceptable wind speed at lift-off has consequently increased to 14 m/s.
• Accessibility of equipment inside the umbilical tower was maximised.
• All servicing and control equipment that was not absolutely necessary in the launch area was moved to a safe distance, thus allowing access to the equipment until just a few minutes before lift-off, and also reducing vulnerability in the event of an accident during the launch.

ELA2 has been operational since March 1986. The pad has been adapted to the Ariane-4 launcher, which made its maiden flight in June 1988. Arianespace will continue to use the facility until about 1999, by which time it will have launched about 100 vehicles at a rate of 8 to 10 per year.

Some small disadvantages, however, still remain:

• Despite a clear improvement over ELA1, vulnerability to an accident at lift-off is still relatively high.
• Although it offers great advantages, separation into two areas has the disadvantage that the umbilicals have to be disconnected from the upper stages in the preparation area and reconnected in the launch area. The newlinks then have to be checked again, and the total time lost is about 36 hours.
• The computerised control system for monitoring and controlling launcher propellants, fluids and electrical systems during check out and count down operations is still too centralised. In particular, non-separation of servicing from launch vehicle parameters leads to some operational constraints.

ELA2 is nevertheless a high-performance launch facility which is well suited to the most complex version of the Ariane-4 vehicle, he 44L, with seven liquid-fuelled stages.

Design and operations philosophy of the Ariane-5 ground facilities

The design of the Ariane-5 ground facilities began in 1987, upon ESA's approval of the Ariane-5 development programme. There were five major requirements:

• custom designed and built for the Ariane-5, a heavy-lift vehicle which is based on a different concept than its predecessors (One main, 155-tonne cryogenic stage, flanked by two solid propellant boosters weighing 230 tonnes each. On top of the main stage are the conventionally liquid-fuelled upper stage, the vehicle equipment bay, the payloads and fairings.)
• a capacity of eight launches a year with a one-month interval between launches
• a low vulnerability, particularly in the eventof a launcher explosion during the count down or lift-off phase (In the case of an accident, the maximum amount of time foreseen to return the site to operational status is six months.)
• good availability, safety, reliability and maintenance, the first two criteria having priority
• optimisation of the cost of launch operations
• local manufacture of most of the propellants, in order to avoid transporting large, hazardous items across Europe and the Atlantic Ocean.

The philosophy behind the Ariane-5 ground operations is closely linked to the design of the launch site, and is based on the following principles:

• Full mechanical integration is performed at the Launcher Integration Building, without any intermediate functional checks so that the functional check scan be carried out in parallel on all the sub-assemblies.
• Electrical checkout equipment and procedures used at ELA3 for the launcher stages are identical to those used by the manufacturing contractors in Europe, thus allowing comparisons and the optimisation of procedures.
• Operations and checkouts are highly automated to improve reproducibility and safety.
• The launcher is fully checked out at the Launcher Integration Building prior to payload integration.
• The roll-out to the launch area takes place just before the final countdown for main-stage fuelling, thus limiting the time that the launcher is exposed to the outside environment. In addition, the vehicle can remain in the launch area if the launch is delayed, provided that no work on the launcher or its payloads is needed.

The Ariane-5 dedicated grounds cover about 2100 hectares and include the following units (Fig.1):

• the booster area, comprising the Solid Propellant Plant, the Booster Integration Building, the test stand, and booster recovery and expertise facilities (see ESA Bulletin No. 75, The Ariane-5 Booster Facilities)
• the Ariane launch complex No. 3 (ELA3) (Fig.2), which includes four main installations (the Launch Control Centre, the Launcher Integration Building, the Final Assembly Building, and the launch pad No. 3) and will be equipped with two mobile launch platforms or launch tables.
• Other systems, like fluids production and processing, remote checkouts and rail tracks.

Construction work on ELA3 began in mid-1988. Some of the facilities are already being used for the development and qualification of the Ariane-5 launcher elements and stages:

• boosters are being tested at the booster test stand, where seven to eight tests are being carried out between 1993 and 1995
• cryogenic main stage 'hot tests' are being performed using the launch pad as the test stand. This eliminates the need for a stage test stand in Europe, and at the same time allows the qualification of the ground facilities, procedures and operating teams. Development and qualification tests are scheduled in 1994 and 1995.

The first two Ariane-5 qualification flights are scheduled for late 1995 and early 1996. The operational lifetime of Ariane-5 is expected to last until at least 2015.

Figure 1. An aerial view of the launch facilities, seen from the north

Figure 2. Components of the Ariane launch area No. 3, ELA3

Fluids manufacturing and processing facilities

The Ariane-5 main stage will carry about 130 tonnes of liquid oxygen, 14 times the volume of the present Ariane-4 third stage. A production plant, which was already on the ELA2 site for Ariane-4, has been upgraded to Ariane-5 requirements. It liquefies air to produce liquid oxygen (LOX) and liquid nitrogen (LN2). It can produce 14 cubic metres of LOX and 60 cubic metres of LN2 per day. The liquid oxygen is stored in five mobile tanks with a capacity of 140 cubic metres each and a sixth tank with a capacity of 20 cubic metres. The nitrogen production capacity will soon be doubled to cope with increasing needs at the Guiana Space Centre's different sites. On the same site, air and helium are compressed and fed into special underground networks (Fig.3).

The Ariane-5 will also carry 13.5 times the volume of liquid hydrogen that the present Ariane-4 carries (27 tonnes on an Ariane-5 as opposed to 2 tonnes on an Ariane-4). The traditional procurement of imported hydrogen containers was not suited to Ariane-5 needs in terms of logistics, economy and safety and it was found that the best solution was to invest in a new, on-site, highly automated liquid hydrogen production plant (Fig.4). The new plant, which has been operational since 1992, produces liquid hydrogen by reforming methylalcohol. It can produce up to 33 cubic metres per day, to feed five 320 cubic metres mobile storage tanks. Before each launch, three of the tanks are transported by road to the launch area, a distance of about 2.5 km. Specially designed trailors equipped with a hydraulic hoisting system and rolling on eight axles(a total of 64 wheels), carry the tanks. After launch, these tanks are carried back to the production plant and reconnected to recover the 'boil-offs'. This recovery drastically reduces fluid loss during transport and transfer.

Launch complex No. 3 - ELA 3

The basic concept used in the design of ELA2 has also been used for ELA3: separate preparation and launch areas. This concept has been adapted to the Ariane-5 vehicle, which is larger but simpler in design than Ariane-4.

Experience gained from ELA2 has been fully exploited in the design of ELA3:

• Vulnerability to accidents has been significantly reduced by simplifying the launch area: ELA2's sensitive mobile servicing gantry, which provides access to the vehicle at different levels and protects it from the weather, has been replaced by a fixed Final Assembly Building (BAF), located beyond the safety distance from the launch pad. The launch vehicle is only rolled out from the BAF to the launch area on its mobile platform for the final count down (about eight hours before lift-off).
• The umbilical disconnection and reconnection process has been eliminated by using a simplified umbilical tower fixed on the mobile launch platform. The umbilicals follow the launcher from the beginning to the end of operations. This change was possible because the upper part of Ariane-5 is simpler than the Ariane-4's, and most of the umbilical connections can be made directly between the launch platform and the lower part of the vehicle.
• The computerised servicing check out systems (remote monitoring and command of ground energy supply, airconditioning, fire detection and other systems) are independent of the launch vehicle checkout (remote control of vehicle fuelling, pressurisation, on-board electrical sytems and count down procedures until lift-off).

Built near the ELA2 site, ELA3's two areas are:

• the launcher preparation area, which is composed of three operational buildings: the Launcher Integration Building (BIL), the Final Assembly Building (BAF), and the Launch Control Centre (CDL3)
• the launch area (ZL3).

The launch area is located about 1800 m to the north of the preparation area. The Launcher Integration Building is about 400 m from the Control Centre and 600 m from the Final Assembly Building. These distances are based on the results of safety studies performed during the early design phase and take into account pyrotechnics regulations.

The twin rail track connecting the Launcher Integration and Final Assembly Buildings follows a curved path and is 1200 m long. The same track continues beyond the Final Assembly Building to the launch area, a distance of 2700 m.

Launcher Integration Building (BIL)
The Launcher Integration Building (BIL) is a steel structure that is 127 m long, 31 m wide and 58 m high (Fig.5). It is divided into three parts: a storage hall, a main-stage erection hall, and an integration hall.

Figure 3. The underground helium storage network being built

Figure 4. The liquid hydrogen plant which produces liquid hydrogen for both the Ariane-4 and Ariane-5 programmes

Figure 5. The Launcher Integration Building (BIL) with the storage hallin the foreground. A mockup of the lower composite has been rolled out of the integration hall on a mobile launch platform. In the background, the Final Assembly Building is under construction (September 1993)

Storage hall
Upon their arrival from Europe after being transported by sea and road, the 30 m-long cryogenic main stage, the vehicle equipment bay and the upper stage, are stored in their shipping containers in the storage hall. The cover of the cryogenic main-stage containeris removed, and the main stage is lifted out of its container and onto the erection supports. This hallis covered but not air-conditioned.

Main-stage erection hall
UThe main-stage erection hall is located in the rear part of the storage hall. It is fitted with a gantry for the erection of the main stage from the horizontal transport position to the vertical assembly and flight position. This hall is also covered but not air-conditioned.

Integration hall
UThe integration hall is separated from the erection hallby a sealed sliding door. Another door allows the boosters to be rolled in from the Booster Integration Building, in the vertical position on their transport trolley. Integration takes place on the mobile launch platform , i.e. the launch table. This hall is air-conditioned.

A seven-tiered steel structure, built above the launch table, provides access to the different levels for assembly and checkout operations. Special holding arms keep the main stage in a precise position during integration, until the mechanical connections to the boosters are made.

A third sliding door allows the whole lower composite (the main stage plus the upper stage, the vehicle equipment bay and the boosters mated on the launch table) to be rolled out in the launch position.

Operations performed
The operations performed in the Launcher Integration Building take 13 days and include:

• mechanical integration of the main stage (Fig.6), upper stage, vehicle equipment bay and solid boosters on the launch table
• electrical and pneumatic connection of the umbilicals
• leak checks and functional check outs
• installation of pyrotechnic and additional equipment, dynamic flight control and overall electrical checkout, and preparation for transfer to the Final Assembly Building.

Roll-out is carried out in a no-voltage configuration, with automated monitoring of pressure inside the main stage, to preserve the integrity of the common bulk head between the oxygen and hydrogen tanks.

Figure 6. The 'battle ship' version of the cryogenic main stage being assembled in the Launcher Integration Building. This reinforced stage will be rolled out to the launch pad for static hot firing tests ('battleship testcam paign')

Final Assembly Building (BAF)

The Final Assembly Building (BAF) is a steel structure that is 85 m long, 52 m wide and 83 m high, and is fully air-conditioned.

It is divided into four main parts:

• The payload encapsulation hall, which is air-conditioned in the Category 100 000 with respect to cleanliness.
• The integration hall (Fig.7) which has a lower part that allows access to the lower composite, in the same way as in the BIL, and an upper part, also Category 100000, that allows access to the vehicle equipment bay, the payloads and the fairing. For the most common type of launch, one with a double payload, the lower payload is lifted through a clean chimney and mated directly onto the vehicle equipment bay. The upper composite is then mated on top.
• Other facilities are the clean storage area; the main airlock for receiving payloads and small launcher items; and the main vertically-sliding door which is 24 m wide and 62 m high to allow the vehicle to be rolled in and out.

Figure 7. An artist's impression of the integration hall in the Final Assembly Building, with a launcher mounted on the mobile launch table, and staff on mobile accessplatform working at different levels

Operations performed
The operations performed in the Final Assembly Building take eight days and include:

• roll-in from the Launcher Integration Building into the integration hall; mating of the upper payload onto the 'Speltra', a flight structure for multiple payloads. in the encapsulation hall
• main-stage purging; assembly of the two fairing half-shells onto the Speltra, thus making up the upper composite; and transfer of the lower payload to the main airlock
• upper and lower payload checks; hoisting of the lower payload and mating on the launcher
• hoisting and mating of the upper composite; and preparation of the upper stage, solid boosters and main stage
• fitting off light batteries on the stages and the vehicle equipment bay; payload checks; and final inspections
• loading of the upper stage with mono-methyl hydrazine (MMH) (automated and remotely controlled from the Control Centre) and the attitude control system with hydrazine (manually); and a dry run of the general launch count down to check range safety interfaces and tracking and telemetry stations
• automated and remote loading of the upper stage with N2O4; payload arming; and upper part inspection
• launcher arming; remotely controlled pressurisation of the main stage and booster high pressure vessels; and remotely controlled loading of the main-stage liquid heliumsphere
• roll-out to the launch area.

Many of these operations form part of a typical launch count down sequence, which is usually carried out on the pad. However, in order to reduce launcher vulnerability and keep the launch pad as simple as possible, the operations are carried out in the BAF ata safe distance from the pad.

Construction of the BAF started in mid-1993 and should be completed during the first quarter of 1995.

Launch Control Centre and check out systems

The Launch Control Centre (CDL3) (Fig.8) is made up of two main areas:

• an office and computer area
• an area housing two fully independent vehicle checkout control rooms (allowing the monitoring of two launchers simultaneously), and three payload control rooms. That area is reinforced to protect personnel and equipment during a launch.

The checkout systems are used for remote control and command of electric and fluid processes, both for the ground facilities and on the launcher itself. Four main sub-assemblies have been developed:

• the utilities checkout system
• the operational checkout systems
• the upper section checkout system
• the payload checkout systems.

Figure 8. Launch Control Centre No.3, which includes two identical control rooms and three payload control rooms

Utilities checkout system
The utilities checkout system(CCS) (Fig.9) is used to monitor and control remotely the site's power, air conditioning, fire and gas detection systems. These controls are needed on a permanent basis, and have no direct link to the launch vehicle. The fully backed-up system includes several consoles in the Control Centre connected to front-end processors located in each ELA3 building and inside the launch table, and a 'supervisor' that automatically detects malfunctions and switches to the back-up system. In case of a technical alarm during non-working hours, the system uses the paging network to notify the appropriate on-call technicians.

Figure 9. Technicians use the utilities checkout system to monitor all sytems that do not directly interface with the vehicle, such as power, air conditioning and fire detection systems

Operational checkout systems
The operational control and checkout systems (CCO) (Fig.10) are two independent command and control chains for the management of the launch vehicle's fluid and electrical systems until lift-off, and the corresponding ground interfaces. Each system has a dedicated control room in the Control Centre, and can be connected to either launch table, thus allowing the monitoring of two launch campaigns simultaneously (with one vehicle in the Launcher Integration Building, and the other in the Final Assembly Building orin the launch area). The system architecture includes front-end processors located inside the launch table and in the launch area terminal building, processing units located in the Control Centre, and networks and dialogue peripherals to complement the control room consoles.

Each of the two operational control systems is fully backed up, and includes an independent safety chain that allows a return to a safe configuration, independently of the hardware and software status of the functional systems. On yet another level, a fully independent manual system can override the automated systems to restore a safe environment in case of failure, in particular through cryogenic main-stage draining.

A new philosophy has been adopted for the Ariane-5 checkout systems, representing an innovation in the Ariane programmes. A whole 'family' of checkout systems is being developed using the same specifications for the 'stage' checkouts in Europe and in Guiana, as for the CCO in Guiana. This approach has two main objectives:

• to minimise development costs
• to ensure that controls among the different checkout systems are standardised, so that the same stage-level tests performed at the production sites in Europe can be repeated during the launch campaign in Guiana and can be compared in a coherent way.

Figure 10. One of the two dedicated control rooms with the operational control and command system consoles

Upper section checkout system
This system is used for the functional checkout of the upper composite wiring before and after the integration of each unit, i.e. the Speltra, fairing, and payload adaptors.

Payload checkout systems
The payload checkout systems allow permanent control and command of the spacecraft during assembly and roll-out operations. They are provided by the spacecraft manufacturers.

The main checkout system is located in the S1, a payload processing facility 20 km from ELA3. The checkout terminal equipment(COTE) is located closer to the spacecraft: in the S3 payload fuelling facilities during fuelling or apogee motor integration, and in the Final Assembly Building and inside the launch table during payload encapsulation, roll-out and count down. The COTE is monitored through remote consoles located in S3 or in the Control Centre. During roll-out operations, the remote consoles are linked to the COTE by radio frequency links.

Launch tables and launch zone

The ground facilities include two identical launch tables, allowing a minimum interval of one month between two consecutive launches. Each table is a mobile launch platform serving as a support for the vehicle from the beginning of integration until lift-off, and accommodating fluids, checkout, power supply and air-conditioning systems. Each table is a steel structure which is 25 m long and 21 m wide, and weighs about 1000 tonnes without the launcher. It travels along a twin railtrack on 16 two-axled bogies at a maximum speed of 4 km/h, and is pulled by two special tractors. The tables also incorporate the umbilical mast and all the ground-to-on board electrical and fluid connections.

The launch area (ZL3) (Fig.11) is of a very simple and flat design, and is used only for the final countdown. It comprises:

• a concrete launch pad foundation to anchor the launch table. The foundation has a central flame trench with a water-cooled steel deflector for the cryogenic main stage engine. This trench is flanked by two covered, curved trenches for the two solid-propellant boosters. The outlets of the trenches are flooded with water to reduce noise. Test campaigns have been carried out in Europe with small-scale models of the Ariane-5 vehicle and the launch area in order to simulate and optimise the noise reduction systems
• a low terminal building adjoining the pad, housing the electrical, command and fluid equipment, and the ground-to-table interfaces (Fig.12)
• mobile tanks for storing liquid oxygen, hydrogen and nitrogen, located about 200 m from the pad
• a pool for burning the vented gaseous hydrogen, a water tower feeding the various deluge operations, and four lightning protection towers.

Operations at the launch area include, after roll-out and reconnection of the table:

• remote controlled countdown operations: six hours for purging, loading, topping up and pressurising the main stage with liquid oxygen and hydrogen; and activating and checking the on-board electrical circuits
• final synchronised sequence: a six-minute, fully automated, sequence of controls and commands carried out by the operational checkout system and synchronised with the overall range countdown.

Figure 11. A lower composite mockup being rolled away from Launch Pad No.3. Between the lightning protection towers (on left, with red tops) is the low terminal building which houses the electrical command and fluid equipment, and the ground-to-table interfaces. One of the two deflectors for solid booster exhaust can be seen on the left (below the lightning tower), and the water tower is in the centre of the photo. The Atlantic Ocean is only a few kilometres to the north.

Figure 12. Inside the low terminal building, with the cryogenic feeding lines and all electrical and control systems for an automated, remote countdown management from the Control Centre (Photo: Bernard Paris)

Range modernisation

In addition to the investments in the dedicated Ariane-5 facilities, the CNES support systems at the Guiana Space Centre are being upgraded or replaced by systems that are more modern and reliable and which are compatible with Ariane-5. ESA is financing the majority of the project while CNES is performing the engineering, procurement and implementation.

A modernisation programme, called CSG 2000, began in 1991. It includes:

• Tracking and flight path quick-look display: upgrading of radars, and renewal of data processing systems in order to ensure a lifetime until the year 2010 or 2015, to improve flight safety performance and to reduce running costs.
• Ground communications system: renewal of the operational and business communications systems, based on a fibre optic network with central configuration management, which will include new telephones, faxes, intercoms, and data and video terminals.
• Telemetry and flight termination systems: adaptation of the processing system to the Ariane-5 telemetry format; upgrading of antennae; extension of data storage, data transmission and remote control of ground stations. For launches into Geostationary Transfer Orbit (GTO), ground stations are located in Kourou, Natal (Brazil), and Ascension Island. A fourth station will be located in either Eastor South Africa.
• Weather forecasting, safety and operations coordination: construction of a new mission control centre (called Jupiter 2) with more reliable, automated configuration and count down management systems; developmentof new planning software and general space-port-wide safety coordination; improvement of weather observation, statistics storage and forecast systems.
• Other new investments including photo and video systems (including infrared tracking cameras), construction of a large conference room, a newspace museum, new launch observation sites, and new back-up energy supply and air conditioning installations.

These projects are being implemented without hindering current Ariane-4 launch operations. Some of the projects are partially implemented and qualified, and are gradually providing support to Ariane-4 missions.

Testing and qualification of the ground facilities

The use of the launch pad as a test stand eliminates investment in a specialtest stand in Europe but, on the other hand, scheduling of ground and flight hardware qualifications is more inter dependent and has to be done more carefully. Each subsystem is tested at the supplier's premises in Europe before it is shipped to Kourou. Another test is performed at the subsystem level after installation in Kourou (called Phase 1), and is followed by a series of tests (Phases 2 to 5) in which more and more subsystems and more and more automated control and command systems are added, before the actual, global system test (such as a hot test of he cryogenic main stage on the launch pad) is performed.

In 1991, the utilities checkout system was installed and checked; it has been operational since that October. In 1992 and 1993, the first fuelling tests of a main-stage mockup (called the 'battleship' version) were performed on the launch pad. They validated the ground systems and manual procedures for handling liquid oxygen, liquid hydrogen, nitrogen, and helium. Related systems were also tested: venting and burning of the Vulcain engine cooling hydrogen, fire extinguishing, water deluge (Fig.13) and associated control and command systems.

In 1994, the first operational control and command system (CCO) is being installed and tested, to allow the first main stage hot tests ('battleship' campaign) in the same year. One maturation (M) and one qualification (Q) campaign are scheduled for late 1994 and early 1995 using flight-type main-stage reservoirs and the Vulcain engine. During these campaigns, nominal as well as some non-nominal situations such as an aborted launch are rehearsed, and the performance of the backup and the safety systems is verified.

A major mechanical validation campaign, called MDO1 was performed in September 1993 in the Launcher Integration Building (Fig.5), with the integration of two boosters and one main-stage mockup of the mobile launch platform. Three more major mechanical validation campaigns are scheduled before the launch campaign for the first flight (in 1995). They will involve, apart from the Launcher Integration Building, the Final Assembly Building and the launch pad.

Figure 13. Testing the water deluge system on the launch pad. A booster mockup (in beige) on its launch platform is on the far right. The three trenches for the exhaust from the main engine and the two solid boosters are at the bottom centre

Closing remarks

The Ariane-5 ground facilities and range modifications will be ready for the first Ariane-5 launch at the end of 1995. Before that time, the facilities will be used for static test firings of the solid boosters and the cryogenic main stage. They will also be used for Ariane-5's two qualification flights. The total investment is expected to be roughly one billion ECUs, which includes the cost of operations and testing until the first commercial flight in 1996. The facilities are then expected to be used commercially for at least 100 launches. The aimis to retain, with Ariane-5, the 50% share of the commercial launch market that Arianespace currently enjoys with Ariane-4.

The ground facilities will satisfy all of their design requirements. The objective of eight launches per year with the possibility of two successive launches one month apart, will be easily achieved because two launch campaigns can be conducted simultaneously with, for instance, one launcher in the preparation phase in the Launcher Integration Building while a second one is in the Final Assembly Building and launch area. This is possible because ELA3 has two operations rooms, two launch tables and two operational checkout systems.

A low vulnerability rate has also been achieved through the very simple design of the launch area, stripped of all but the most essential equipment, and through the use of mobile storage facilities and two launch tables. Good reliability, maintenance, availability and safety have been made possible by building redundancy into the fluids process and operations command and control systems, and by setting up safety systems that are completely independent of the operational systems. The very high degree of automation in operations also makes for considerable gains in availability during countdown and safety since the risk of human error has been drastically reduced.

During the Ariane-5 development phase (until and including the second qualification flight in 1996), CNES and its European subcontractors are operating the ELA3 facilities. The industrial structure for the subsequent, commercial phase, i.e. the companies or groups of companies that will be responsible for the maintenance and operations of the various systems, is now being established. Arianespace will manage the operation. The industrial organisation must take into account the resources and energy needed for the overlap phase between 1996 and 1999 during which the ELA2 and ELA3 complexes will operate simultaneously to ensure a smooth transfer from Ariane-4 to Ariane-5. Special production facilities, such as the booster area and the liquid hydrogen and oxygen plants, are operated under direct industrial responsibility.

The short duration of launch operations (22 working days) contributes to the objective of reducing launch costs by 10% compared to the cost of launching the most powerful version of Ariane-4 (the 44L version). This short launch campaign is possible because of the design of the facilities and the way operations and the principles that apply to them are organised: automation, checks done in parallel for all the stages and the fact that checks done in Europe can also be performed in Kourou.

With minor modifications, these facilities can also be compatible with Ariane-5 crewed and cargo missions - now under study - to future space stations.