United Launch Alliance's dominance is fading as the company remains tied to expendable rocket technology, according to a deep dive by Stephen Clark. Meanwhile, Italian provider Avio is capitalizing on SpaceX's Falcon 9 capacity constraints. Avio CEO Giulio Ranzo stated during a September 10 earnings call that SpaceX has "gone captive," turning away new commercial orders and driving customers to Avio's Vega C rocket, which likely costs around $60 million per launch. Some rejected customers lobbied European institutions at the International Space Summit in Paris for subsidies to offset higher European launch costs.

On Tuesday, a Vega C rocket successfully launched from French Guiana, carrying the European Space Agency's FLEX Earth Explorer satellite and Copernicus Sentinel-3C into low-Earth orbit. The mission utilized a new Vespa launch adapter to stack both satellites. ESA's Simonetta Cheli praised the dual-satellite deployment achievement.

French startup Sirius Space Services successfully test-fired its STAR-1 rocket engine prototype at Airborne Engineering's facility in southern England. The liquid oxygen and methane-fueled engine, designed to produce 55 kN of thrust, completed multiple successful ignitions with all critical subsystems operating together.