The vehicle is being built on a hybrid foundation that draws from Northrop Grummans Antares platform and Fireflys Alpha rocket technology.

Northrop Grumman Corporation has invested $50m into Firefly Aerospace to further advance production of their co-developed medium launch vehicle, now known as Eclipse. The companies continue to make progress in the development of Eclipse flight hardware, with qualification testing underway and more than 60 Miranda engine hot fire tests performed to date.
Jason Kim, CEO of Firefly Aerospace, said: “Firefly is incredibly grateful for Northrop Grummans investment that further solidifies our first-of-its-kind partnership to build the first stage of Antares 330 and jointly develop Eclipse. Eclipse represents two powerful forces coming together to transform the launch market with decades of flight heritage, a rapid, iterative approach, and bold innovation. With a 16 metric ton to orbit capability, Eclipse is a sweet spot for programs like NSSL Lane 1 and a natural fit to launch proliferated constellations in LEO, MEO, GEO and TLI.”
Built upon Northrop Grummans Antares and Fireflys Alpha rocket, Eclipse offers a significant leap in power, performance, production cadence and payload capacity. The launch vehicle retains the flight-proven avionics from the Antares programme with additional upgrades, including a larger 5.4 meter payload fairing. Eclipse also utilises the same first stage Firefly is developing for Antares 330 and retains scaled-up versions of Alphas propulsion systems and carbon composite structures, allowing the team to rapidly build and test Eclipse with significant production efficiencies and economies of scale.
Firefly utilised the same patented tap-off cycle architecture from Alphas Reaver and Lightning engines for Eclipses Miranda and Vira engines, and completed mission duty cycle with a 206 second Miranda hot fire, matching the longest time the engine will burn during a flight. Following several development test campaigns, flight hardware has been manufactured for the common dome propellant tanks, engine bay and interstage.
Wendy Williams, Vice President and General Manager, Launch and Missile Defense Systems, Northrop Grumman, added: “Eclipse gives customers the right balance between payload capacity and affordability. Our partnership with Firefly builds on our capacity to provide crucial spaced-based communication, observation, and exploration for civil and national security customers.”
Filling a void in an underserved market, Eclipse is equipped to deliver 16,300 kg of cargo to low Earth orbit or 3,200 kg of cargo to geosynchronous transfer orbit. Eclipse will first launch from Wallops Island, Virginia, as early as 2026 and is able to support space station resupply, commercial spacecraft, critical national security missions and scientific payloads for the domestic and international markets.