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:
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.
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:
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 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:
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:
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:
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.
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:
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:
The Ariane-5 dedicated grounds cover about 2100 hectares and include the following units (Fig.1):
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:
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
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.
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:
Built near the ELA2 site, ELA3's two areas are:
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)
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.
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.
The operations performed in the Launcher Integration Building take 13 days and include:
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')
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:
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
The operations performed in the Final Assembly Building take eight days and include:
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.
The Launch Control Centre (CDL3) (Fig.8) is made up of two main areas:
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:
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:
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.
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:
Operations at the launch area include, after roll-out and reconnection of the table:
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)
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:
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.
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
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.