AST SpaceMobile to build own rocket with $1.3bn Firefly engine deal

AST SpaceMobile will spend more than $1.3 billion in cash and shares on rocket engines from Firefly Aerospace, betting that vertical integration can protect its satellite deployment schedule from launch partners' failures.

The three-year agreement, disclosed by Firefly Aerospace, covers 36 engines: 27 Miranda units and nine vacuum-variant Vira models. AST SpaceMobile also gains a perpetual licence to Firefly's engine designs and plans to build a US production facility to manufacture them.

The move follows a concrete setback. A Blue Origin New Glenn rocket failed during a hot fire test, and the fallout appeared to scupper AST SpaceMobile's satellite deployment targets for the year, pushing them into 2027.

What is AST SpaceMobile actually building?

The new vehicle is called Blacklift. AST SpaceMobile hopes to fly it late in 2028. It plans a 20-tonne rocket capable of carrying up to five BlueBird satellites per launch.

The company does not intend Blacklift to become its only route to orbit. It will slot the vehicle into a wider range of launch options rather than rely on it solely. AST SpaceMobile still holds agreements with external launch companies covering more than 100 BlueBird satellites across 2027 and 2028.

Founder, chair and CEO Abel Avellan said Blacklift would deliver "regular unconstrained access to orbit" and contribute to some of the "most favourable owners' economics in the industry". The company described end-to-end vertical integration as a "long-held" goal.

That claim is vendor optimism, not delivered capability. The rocket does not exist yet, and its first flight is at best three years away. The engine statistics, by contrast, are measurable.

How proven are the engines?

Firefly Aerospace stated the Miranda engine has completed more than 175 hot fire tests spanning in excess of 4,200 seconds of cumulative firing. It has also completed a "flight-like test" at a 110% thrust level. The engine produces 230,000lb/ft of thrust.

For AST SpaceMobile, those numbers matter directly. Its 2026 deployment plans were disrupted by a launch partner's test failure, so engine maturity is the variable most likely to determine whether Blacklift holds its late-2028 target.

Firefly Aerospace CEO Jason Kim framed the stakes plainly. The engine is the "hardest, highest-stakes" element in any rocket build, he said.

What changes for operators and partners?

AST SpaceMobile's business depends on placing large numbers of BlueBird satellites into orbit quickly to serve its direct-to-device mobile partnerships. External launch capacity has proven to be the bottleneck: a single failed test at Blue Origin was enough to move deployment targets by roughly a year.

Owning an in-house launch capability, even a partial one, changes the risk calculation. It gives AST SpaceMobile a floor under its deployment schedule rather than a guarantee of faster rollout. The company retains more than 100 satellite launches under existing external agreements, so Blacklift functions as insurance and capacity top-up rather than a replacement strategy.

The $1.3 billion-plus engine commitment, spread over three years and paid partly in shares, also signals capital priorities. AST SpaceMobile is spending on launch assurance in parallel to its constellation build.

The first hard checkpoint arrives late in 2028, when Blacklift is slated to fly; until then, the company's deployment pace rests on its external launch partners and the more than 100 satellite launches already contracted for 2027 and 2028.