LE BOURGET - After years of trying to sell the space division of Italian aerospace propulsion specialist Avio SpA, private-equity investor Cinven Ltd. is preparing to unload a majority of its 81% stake in the company by the end of this year, according to Avio's chief executive.

“The process of due diligence is already started,” Pier Guliano Lasagni, CEO of Avio, told reporters on the sidelines of the Paris air show here. “I feel we are now much closer.”

Avio, which is majority owner of Vega rocket prime contractor ELV SpA, develops the solid rocket boosters that power Europe's Ariane 5 rocket. The company is also supporting Ariane prime contractor Airbus Safran Launchers in developing the new P-120 solid-fueled rocket stage that will serve as both the strap-on booster of the next-generation Ariane 6 and first stage of the enhanced Vega C.

“We have a real partnership with them in this company,” Lasagni said. “In the past we have worked with Safran on propulsion systems; now it's different in that we own ELV, the prime of Vega, and they bring Airbus, which is the prime contractor on Ariane, and I think we have to reach an equilibrium between the bigger and the smaller.”

European private-equity investment company Cinven purchased Avio in 2006 from Carlyle Group and Finmeccanica for €2.57 billion ($3.3 billion). The Italian aerospace conglomerate, which holds a 14% stake in Avio, is seen as the most likely buyer.

In the meantime, Lasagni said Avio is focused on developing the new P-120 that will power the next-generation Vega C, which he said is supposed to enter service in 2019.

The company also wants to develop the Vega-E, a rocket that would lift twice the payload of the current Vega, which delivers satellites weighing up to 1,500 kg to low Earth orbit. In addition, Avio is doing some work on a new LOX/Methane engine with Russia to replace the Vega's Ukrainian-built upper stage. However, Lasagni said he expects Germany to play a role in the development through its contribution to the European Space Agency (ESA) launch vehicle program.