VEGA

 
 

Avio (Advanced Vision Into Aerospace) * European Launch Vehicle (ELV S.p.A.)

The European Space Agency will definitely proceed with the development of the
VEGA (Vettore Europeo di Generazione Avanzata) launcher using Ariane booster technology. VEGA is a three-stage launch vehicle using solid motors. The first launch is planned for 2007. It is planned that Arianespace would operate and commercialise the  launch service from Kourou. Prime contractors will be FiatAvio and EADS. VEGA will consist of three solid propellant stages and a liquid propellant upper stage. The first stage P80 Advanced Solid Booster will also be used to increase the performance of the Ariane 5 in its twin-solid rocket booster system, with new features such as a new gimballing nozzle. The second stage will be Italy's Zefiro motor. The third stage be a modified Zefiro booster and the upper stage an Attitude and Vernier Upper Module with storable propellants. VEGA will be able to place about 1.5 tons into an SSO. The final decision on the development of the small launcher VEGA is expected to be taken in October 1999 by the ESA Council.
After about two years of defination and consolidation activities, the current VEGA configuration, including the new P80 FW first stage, two additional solid-propellant stages Zefiro (the Zefiro motor development was initiated by FiatAvio under company funding and contracted by the Italian Space Agency) as, respectively, second and third stages, and the AVUM upper modul, had been established and was ready for development as an ESA program. The specified mission for VEGA is: launch of a payload of up to 1500 kg into a circular 700 km-altitude polar orbit. VEGA will be able to launch satellites for a wide range of missions and applications, into orbits with a range of inclinations from 5.2 degrees to SSO, with altitudes between 300 and 1500 km, and with payload masses ranging between 300 and 2500 kg from Kourou. VEGA is designed as a single-body vehicle composed of three solid-propulsion stages, an additional liquid-propulsion upper module, and a fairing for payload protection. The three solid stages perform the injection of the upper composite into a low-altitude orbit. The upper module, called AVUM ( Attitude and Vernier Upper Module), is used to improve the accuracy of the primary injection, to circularize the orbit, and to perform the empty-stage to deorbiting manoeuvre.
 

First stage: The first stage is based on the adoption of the new P80 FW solid-rocket motor being developed through a parallel Program slice. P80 FW Technology Choises: CFRP monolithic carbon fibre case, HTPB 1912 propellant. The P 80 FW maximum vacuum thrust is 3015 kN. The nozzle has a throat diameter of 496 mm and an expansion ratio about 1: 16. The nominal firing time is about 110 seconds. In addition to the P80 motor, the first stage is composed of the structural elements needed to connect it to the second stage (interstage 1/2 aft part) and to the ground infrastructure (interstage 0/1), and to host the stage avionics. Those airframes are aluminium shells. The rear skirt (interstage 0/1) is a cylindrical structure, while the interstage 1/2 is a conical structure.

Second stage: The propulsion for the VEGA second stage is based on a stretched version of the Zefiro 16 solid-rocket motor, with the propellant mass increased to 24 tons. The new stretched SRM, known as Zefiro 23, employs: A lightweight carbon-epoxy case, HTPB 1912 composite propellant, a moving nozzle, based on flexible-joint technology. The Zefiro 23 maximum vacuum thrust is 1120 kN. The nominal firing time for the second stage is about 77 seconds. The nozzle has a throat diameter of 294 mm and an expansion ratio about 1: 25. In addition to the Zefiro motor, the second stage includes the structural elements needed to connect it to adjacent stages and to host the stage avionics. The interstage 2/3 is an aluminium cylindrical structure.


Third stage:
The VEGA third-stage propulsion is based on a solid-rocket motor with a propellant mass of 9.5 tons, known as Zefiro SRM and derived from Zefiro 16. Zefiro 9 employs a carbon-epoxy filament-wound case, HTPB 1912 composite propellant, and a moving nozzle based on flexible-joint technology. Its maximum vacuum thrust is 317 kN, respectively. The nozzle has a throat diameter of 164 mm and an expansion ratio of 1: 56. The nominal firing time is about 119 seconds. An interstage connects Zefiro 9 to the AVUM, and hosts the stage avionics and the main safeguard unit.

Upper stage: The AVUM (Attitude and Vernier Upper Module) upper stage is composed of two different sections, one hosting the propulsion elements (APM= AVUM Propulsion Module), and one dedicated to the vehicle equipment bay (AAM= AVUM Avionics Module). The APM provides attitude control and axial thrust during the final phases of flight. The total propellant loading will be between 250 and 500 kg, depending on the launcher configuration definition and the mission to be performed.

Upper composite:
The upper composite includes the payload adapter and the fairing. The upper-stage configuration imposes the use of a conical structure in order to provide the required payload standard interface of 937 mm diameter. The reuse of an existing Ariane adapter is foreseen. For the fairing, a two shell configuration has been selected, with a 2.6 m external-diameter cylindrical part and a total height of 7.9 m � including a 3.5 m cylindrical part. The structure is made of two composite shells, composed of aluminium honeycomb and carbon skins.