Development of Europe’s Italian-led Vega small-satellite launcher has remained within its allowed cost limits despite the vehicle’s slower-than-expected ground qualification and the delay, to 2011, of its inaugural flight, according to Arturo De Lillis, head of the launcher unit of the Italian Space Agency (ASI).

Italy is funding the majority of Vega’s development. ELV, a joint venture between Avio of Italy and ASI, is prime contractor for the vehicle, which is designed to place a 1,500-kilogram science or Earth observation satellite into a 700-kilometer polar low Earth orbit.

Early plans for Vega had set a first flight for 2006. That has moved back on multiple occasions and is now set for early 2011. But a final test firing of the redesigned Zefiro 9A third stage was scheduled for late May or early June, and a firm launch date will depend in part on the results.

The vehicle also is being fitted with new software for its flight control.

De Lillis said nonetheless that the program is within the margins set by the European Space Agency (ESA), which permit development budgets to exceed their initial ceilings by 20 percent before being brought back to the agency for a fresh vote on whether to continue.

“Vega is not costing a lot more than what was envisaged,” De Lillis said. “I would say it is comparable to the development of the ground infrastructure of the [Europeanized] Soyuz rocket. All major programs suffer some delays, but costs here are within the 120 percent allowed.”

Vega’s first flight is being handled by ESA. For the subsequent flights, the Arianespace launch consortium of Evry, France, will be taking over and performing a role similar to what it does with the heavy-lift Ariane 5 vehicle and the future European version of Russia’s Soyuz rocket.

Arianespace is in negotiations with the ELV company for five Vega rockets.

Pier Giuliano, head of the space propulsion division of Avio, said Vega’s first major modification after its qualification flight will be to replace its Ukrainian-built Avum upper stage and the Zefiro-9A third stage with a single, more-powerful liquid oxygen-methane engine, which should be in testing in 2012.