Ariane-5 - ESA

1 138 Ariane-5 Ariane-5 Achievements:first European heavy-lift satellite launcher; 9 launches by Mar2001; planned launches 5 in 2001, 6 in 2002, 6 in 2003, 8 in 2004 Launch dates:debut Ar-501 4 Jun 1996 (failed); first success Ar-502 30 Oct1997; first operational flight Ar-504 10 Dec 1999; debut Ar-5 ESV planned2002; debut Ar-5 ECA planned 2002; debut Ar-5 ECB planned 2005 Launch site:ELA-3 complex; Kourou, French GuianaLaunch mass:746 t (Ar-5G), 767 t (Ar-5 ESV), 777 t (Ar-5 ECA), 790 t (Ar-5 ECB)Length:depending on fairing configuration m (Ar-5G), m(Ar-5 ESV), m (Ar-5 ECA), (Ar-5 ECB)Performance:optimised for geostationary transfer orbit (GTO); see separate tablePrincipal contractor:EADS Launch Vehicles (industrial architect)The ESA Ministerial Council meetingin The Hague, The Netherlands inNovember 1987 approveddevelopment of the first Europeanheavy-lift launch vehicle.

2 AlthoughAriane-1 to -4 proved to beremarkably successful, it was clearthat a new, larger vehicle wasrequired to handle the ever-growingsizes of commercialtelecommunications satellites. Thegoal was to offer 60% additional GTOcapacity for only 90% the cost of anAriane-44L, equivalent to reducingthe cost/kg by 44%.At the time of approval, it wasintended that Ariane-5 would also betailored to carry the Hermes mannedspaceplane. Although Hermes waslater shelved, the design can still beman-rated if required. The standard lower composite of stage-1 plusboosters is aiming for a reliability of99%, an order of magnitude greaterthan for ariane -4. Ariane-5 s overallreliability target is LikeAriane-4, it is optimised for dual-satellite launches into is responsible (as designauthority) for ariane developmentwork, owning all the assets entrusts technical direction andfinancial management to CNES,which writes the programmespecifications and places theindustrial contracts on its Launch Vehicles (the formerAerospatiale) acts as industrialarchitect.

3 ESA/CNES were directlyresponsible for the first threelaunches, before Arianespaceassumed responsibility forcommercial operations. The newvehicle is expected to completelyreplace ariane -4 in s ELA-3 and associatedprocessing areas were constructed asdedicated Ariane-5 facilities to permitup to 10 launches annually (8 is thecurrent target). Unlike ariane -4, thepayload assembly is integrated withthe vehicle before they aretransported to the pad only 8 hbefore launch, in order to minimisepad operations. A launch campaigncovers 21 days; the payload is mated6days before launch. The simplifiedpad concept deletes the requirementfor large cryogenic arms on theumbilical tower by feeding thepropellants from below the mobilelaunch table. It also reducesvulnerability to launch are four principal buildings inthe preparation zone: B timent d Int gration Propulseur(BIP) integration hall for the solid-propellant boosters to beassembled and checked out; B timent d'Int gration Lanceur(BIL) launcher integration buildingwhere the core stage-1 is erectedon the mobile platform and theboosters added; was generally successful in October 1997.

4 Anunanticipated roll torque from the main engine causedpremature shutdown of the core stage and resulted in alowered transfer orbit. The phenomenon was allowed foron subsequent flights. (ESA/CNES/CSG) B timent d Assemblage Final (BAF)assembly building where thepayload composite is assembledand erected, the stage-2 tanksfilled and the final electricalcheckout conducted; Launch Centre (CDL-3) for launchoperations with two new 3000 m2S5 payloadprocessing facility came on line in2001, designed to handle four largepayloads simultaneously, includingthe Automated Transfer was the first satellite to useit. A second mobile launch table wasadded in is clear that the mass ofcommercial telecommunicationssatellites destined for geostationaryorbit ariane s principal market will continue to grow. Ariane-5 starget capacity of t into GTO willno longer be able to accommodatetwo satellites per launch essentialfor profitability.

5 The October 1995 ESA Ministerial Council in Toulousetherefore approved the ariane -5E(E=Evolution) programme to increasedual-payload GTO capacity to t,now expected to be available in of the improvement (800 kg)comes from uprating the main engineto the Vulcain-2 model: increasingthrust to 1350 kN by widening thethroat 10%, increasing chamberpressure 10%, extending the nozzleand changing the LOX/LH2mixtureratio. That last element requires thetank bulkhead to be lowered by65 cm, raising propellant mass to170 t. Welding the booster casingsinstead of bolting them together saves2t and allows 2430 kg morepropellant in the top segment,increasing GTO capacity by 300 kg. Anew composite structure for the VEBsaves 160 kg. Replacing the Speltracarrier by the lighter Sylda-5 adds380 kg capacity. Roll control duringburns will be provided by a thruster140141 Cutaway of the ariane -5G vehicle onthe ELA-3 launch pad.

6 (ESA/D. Ducros)Stage-2(L9; EPS: Etage Propergols Stockables)Principal contractor:Astrium GmbH (Bremen) m long; m diameter, t drymassPowered by:Astrium Aestus reignitablegimballed engine providing kN for 1100 s,drawing on up to t of NTO/MMHD esign:this orbit injection stage also ensurespayload orientation and separation. Requiredto nestle inside the VEB under the payloadfairing, it is designed for compactness: theengine is embedded within the four propellantspheres (each m-diameter, pressurised bar by helium). Main structural elementis frustum continuing VEB s frustum at3936 mm-diameter lower face and supportingpayload adapters on 1920 mm-diameterforward faceVehicle Equipment Bay(VEB)Principal contractor:Astrium SAPurpose:carries equipment for vehicleguidance, data processing, sequencing,telemetry and trackingSize:104 cm high; m diameter, 520 kgDesign:internal frustum of a CFRP sandwichsupports upper stage at its 3936 mm-diaforward end; external aluminium cylindersupports payload fairing/carrier; annularplatform carries the electronics.

7 Hydrazinethrusters provide roll control during stage-1/2burns, and 3-axis control after stage firingsPayload Fairing and CarriersPayloads are protected by a 2-piecealuminium fairing until it is jettisoned afterabout 285 s during the stage-2 burn. Primecontractor is Contraves. Three basic lengthsare available: , and 17 m; dia initial main payload carrier is the Spelda,which sits between the fairing andstage-2/VEB, housing one satellite internallyand a second on its top face, under thefairing. Two models: m & 7 m heights. Tobe replaced in 2002 by Sylda-5, sitting insidestandard fairings: 6 versions, mheights, m inner dia. Four extension ringsavailable for fairing, increase heights by m. Some missions can also carry up to six50 kg satellites as passengers on Equipment Bay(VEB) ariane -5G Principal CharacteristicsBoosters(P230; EAP: Etage d Acc l ration Poudre)Principal contractors:EADS Launch Vehicles(stage integrator), Europropulsion (motors) m long, m diameter, 40 tempty massPowered by:238 t of solid propellantgenerates 5250 kN each at launch; 132 sburn timeDesign:motor is assembled in Kourou fromthree sections, each of 8 mm-thick steel.

8 Thetwo lower sections each comprise m-long cylinders. HTPB solid propellantof 68% ammonium perchlorate, 18%aluminium and 14% liner produced and castin casings in Kourou; m-long forwardsection shipped already loaded by BPD fromItaly. Nozzle steering by two hydraulicactuators using flexbearing for 6 recovery for inspection of two boostersets annually using parachutes carried innosecone (GTO penalty 100 kg)Stage-1(H155; EPC: Etage Principal Cryotechnique)Principal contractors:EADS Launch Vehicles(stage integrator), Snecma Moteurs (mainengine), Cryospace (tanks) m long; m diameter, t drymassPowered by:one Snecma Moteurs Vulcaincryogenic engine providing 900 kN at launch,increasing to 1145 kN (vacuum thrust) for580 s, gimballed for attitude control, drawingon 156 t of liquid oxygen (LOX) and liquidhydrogen (LH2) Design:the aluminium tank is divided intotwo sections by a common bulkhead, creatinga 120 m3 LOX forward tank (pressurised bar by helium) and a 390 m3LH2aft tank(pressurised to bar by gaseous H2).

9 Thetank s external surface carries a 2 cm-thickinsulation layer to help maintain thecryogenic temperaturesStage-2(L9; EPS: Etage Propergols Stockable)Payload Fairing and Carriers142 Ariane-5 s VehicleEquipment Bay (VEB)carries the controlsystems. Stage-2 sits onthe inner to install the Vulcain main engine onAriane-5. (ESA/CNES/CSG) Ariane-5 s upper stage is designed forcompactness, nestling the engine amongclustered propellant tanks. (ESA/CNES/CSG)143 The baseline ESC-B cryogenic on the EPC core, simplifyingthe EPS control even these improvements are notenough to remain competitive, asmarket projections predict launchesof paired 6 t satellites will be requiredby 2006. ESA s Council in June 1998therefore approved the Ariane-5 Plusprogramme to meet this will be phased in: Ariane-5 ESV(V=Versatile) will allowmultiple EPS stage-2 reignitions toaccommodate a wider range ofmissions.

10 Stretched tanks add 250 kgof propellant. Coasting betweenburns requires a 6 h life, provided byimproving thermal protection andenhanced (C=Cryogenic) willprovide 10 t ( t for dual satellites)into GTO using the ESC-A cryogenicstage-2 powered by the kNHM7B engine from mass is t, m. Single ignition. Reuses theAr-4 LOX tank and thrust frame,plus the Ar-5 EPC tank is planned for mid-2002 as thefirst ariane -5E the approvalof the Ministerial Council meeting in2001. It offers 12 t GTO capacity in2006 using the ESC-B stage-2,derived from ESC-A. The new 155 kNSnecma Moteurs Vinci engine offersmultiple (1-5) ignitions, drawing on24 t of LOX/LH2. Vinci uses theexpander cycle, in which the turbinesare driven by hydrogen heatedthrough the walls of the combustionchamber before being injected. SI464 s, combustion pressure 280 bar,expansion ratio 280, mixture (LOX/LH2), flow kg/s (LOX/LH2), mass 480 kg,height m, exit diameter will undoubtedly continueto grow, so a 15 t GTO capacity maybe necessary by 2010.