Measuring around 30 metres in length and three metres in diameter, VEGA is the smallest of ESA's three launch vehicles. Weighing around 139 tons in total, the system is capable of transporting payloads of up to 2.5 tons. VEGA was mainly designed to carry relatively small research and Earth-observation satellites into polar or near-Earth orbits. Compared to most other small rockets, however, VEGA enjoys a crucial advantage: on every flight, it can carry several satellites at a time into different orbits.
This is possible because the system consists of four stages, three driven by solid-fuel engines, and a re-ignitable upper stage powered by liquid fuel. Together with Ariane and Soyuz, VEGA makes up an entire family of launchers that is now at ESA’s disposal. This permits serving the entire demand for launching heavy (Ariane), medium (Soyuz), and light payloads (Vega) from the European spaceport at Kourou. So far, all launches have gone smoothly.
The nations participating in ESA's VEGA development programme include Italy, France, Spain, Belgium, the Netherlands, Switzerland, and Sweden. Of these, Italy (65 percent) and France (15 percent) together bear the biggest share. While Germany did not participate in the original development programme, it supplies important elements of the launcher including, for example, the attitude control system.
In 2012, Germany joined the programme to prepare a more powerful VEGA version, and since the end of 2014, it has been participating in the development of VEGA-C. VEGA-C is designed to carry payloads into orbit that are at least 300 kilograms heavier than those of the current version, without any increase in the cost of a launch. The first VEGA-C is scheduled to take off early in 2019.
Even in the early nineties, studies on the development of a launcher for smaller satellites were being carried out in several ESA member states. The reason for this was the growing number of Earth-observation and research satellite programmes and the demand for corresponding launch services. At first, however, it proved impossible to develop a light launcher in parallel to the already ongoing programme to develop the heavy-lift launcher Ariane 5, although demand analyses were positive. It was only in 1998 that ESA initiated a programme to develop a light launcher at the initiative of Italy. On February 13, 2012, VEGA performed its maiden flight from the space centre of Kourou in French Guiana. On that occasion, the light launcher took off from the 'Ensemble de Lancement Vega', the converted launch pad from which the first Ariane launch vehicle flew into space as early as 1979.
Source: Arianespace, Vega User's Manual, Issue 4 Revision 0, April 2014
EEO - elliptic earth orbit
SSO - sun synchronous orbit
LEO - low earth orbit
HTPB - hydroxyl-terminated polybutadiene
NTO - dinitrogen tetroxide
UDMH - unsymmetrical dimethylhydrazine