AST SpaceMobile’s agreement with Firefly Aerospace gives the satellite operator two ways to obtain engines for its planned heavy-lift rocket. Firefly will supply the engines for the first three rockets. AST will also receive a license to manufacture the engines itself. Firefly retains ownership of the designs and can continue supplying other customers.
Announced November 6, 2026, the agreement covers three years and has a stated value of more than $1.3 billion. AST will pay with cash and shares of its Class A common stock. The shares carry restrictions on when Firefly can sell them. The price covers completed engines, manufacturing rights, and engineering support together. Dividing the contract value by the number of engines would combine the cost of all three purchases into a misleading unit price.
Two Engines for Different Parts of Flight
Firefly’s delivery commitment covers 27 Miranda engines and nine Vira engines. Vira is the version designed for operation in a vacuum. A rocket engine’s nozzle directs expanding exhaust to produce thrust. Atmospheric pressure outside the nozzle falls as the vehicle climbs, giving designers a reason to use different versions of a related engine for different stages of flight.
The engines draw on technology Firefly developed for its smaller Reaver and Lightning engines. Firefly reported more than 175 Miranda hot-fire tests totaling more than 4,200 seconds. In one ground test of the 230,000-pound-force engine, Firefly said Miranda ran at 110% of nominal performance and continued for 20 seconds beyond the nominal flight duration of 206 seconds.
The agreement also finances work at Firefly’s facilities. The company identified additional engine test bays in Briggs, Texas, purchases of materials with long delivery times, and expanded engineering and production staffing among its planned uses of the funds. For AST, the manufacturing license has a different purpose: after buying engines for the first three rockets, the operator has the right to produce engines of the same design without acquiring Firefly’s underlying intellectual property.
