New Delhi, Feb. 12 -- In a tightly controlled manufacturing hangar west of Paris, workers put the finishing touches on an enormous silver-colored engine. In just a few days, a similar machine will help propel the most powerful version of Europe's Ariane 6 rocket yet, flying for the first time with four boosters.

On Thursday, the Ariane 64 rocket - named after its four boosters - is scheduled to make its maiden launch from the European spaceport in Kourou, French Guiana, aiming to deploy 32 satellites for Amazon Leo's broadband constellation.

The flagship of Europe's rocket industry is racing in a highly competitive environment against heavy weight players across the world, including the global market leader, Elon Musk's SpaceX.

At Aria...