OrbitalHub

Credits: ESA – J. Huart

The small-payload market is rapidly expanding. Institutional programs (mostly Earth observation and scientific missions) drive this emerging market. In order to meet the demands of the small-payload market, ESA has transformed the small launcher program initiated by the Italian Space Agency (ASI) in the 1990s into Vega, a co-operative project with other Member States within the ESA framework.

The small-payload market consists of satellites up to 3,000 kg and it stands at around five missions per year. There are many classifications for the satellites in this market, so we will present just one classification for informational purposes. The satellites in this class are divided into three categories: micro-satellites (up to 300 kg), mini-satellites (from 300 kg to 1,000 kg), and small satellites (from 1,000 kg to 3,000 kg).

The orbits required for the deployment of these satellites are mainly Sun Synchronous Orbits (SSO) and Low Earth Orbits (LEO). Vega’s in-orbit launch capability benchmark is 1,500 kg into a 700 km altitude polar orbit. Being designed to cope with a wide range of missions, Vega will address the various market requirements for this class of satellites.

Credits: ESA

Vega is a single-body launcher composed of four stages. The first three stages are solid propellant stages, while the fourth stage has a liquid propellant engine. Vega is 30 meters high, has a maximum diameter of three meters and a total of 137 tons at lift-off.

There are three main sections: the Lower Composite, the Restartable Upper Module and the Payload Composite.

The Lower Composite section consists of the first three stages (the solid propellant stages). The first stage is equipped with a P80-FW motor containing 88 tons of propellant. The second stage contains a Zefiro 23 motor with 23 tons of propellant. The third stage consists of a Zefiro 9 motor with 10 tons of propellant and the stage-interfacing structures.

The technology for the three solid-propellant stages (P80, Z23, Z9) is derived from the Zefiro 16 rocket motor. These motors benefit from the experience acquired by Europe in the field of solid propulsion. Each motor is composed of a thermal-insulated carbon-epoxy monolithic case, the solid propellant HTPB 1912, a nozzle, a thrust vector control system driven by two electro-actuators that operate the movable nozzle, and a control unit that provides pitch and yaw control during the flight. Each stage also includes an ignition subsystem, a safety subsystem, and the interfaces to the other stages.

Credits: ESA/CNES-SOV

The P80 engine was designed for the Vega small launcher, and it helps validate technologies applicable to a new generation of solid boosters for the Ariane 5 launch vehicle. This new design was driven by the goal of minimizing recurring costs, a significant reduction being made with respect to the current metal case boosters.

The Restartable Upper Module is the fourth stage of the launcher. It is also known as the Altitude and Vernier Upper Module (AVUM). The AVUM consists of two modules: the AVUM Propulsion Module and the AVUM Avionics Module.

The propulsion system uses NTO (Nitrogen Tetroxide) and UDMH (Unsymmetrical dimethyl hydrazine) as propellants. The propellants are stored in two identical titanium tanks pressurized by helium. Depending on the mission, the propellant load can be between 250 kg and 500 kg.

The avionics system is largely adapted from existing hardware and/or components already under development (namely subsystems already in use by the Ariane 5 launch vehicle).

The Payload Composite section is composed of the fairing and the payload/launcher interface structure. The fairing is composed of two shells that are jettisoned during flight after the separation of the second stage. The payload/launcher interface is an Adaptor 937, which is a standard interface used on the European launchers. Additional payload adapters can be added for multi-payload missions.

Credits: ESA – J. Huart

The dedicated Ground Segment for the Vega launcher comprises of the Launch Zone (ZLV – Zone de Lancement Vega) and the Operational Control Center, all located at the European Spaceport at Kourou, in French Guiana. ESA also built a Payload Preparation Complex that will be used for satellite and equipment unpacking, mechanical inspections, the checkout of the payloads, and the final integration of the payload composite before mounting it on top of the launcher.

On October 24, 2008, the Zefiro 9 rocket engine passed the first qualification test. There is one additional firing test left for the engine. The Vega launcher’s qualification flight is scheduled to take place by the end of 2009.

Credits: Avio SpA (Italy)

ESA is responsible for the qualification of the launch service and also for sustaining the qualification status during the exploitation phase. Ariane Space will be responsible for Vega’s commercialization and launch operations. The expected launch rate for Vega will be up to four launches per year.

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