Cowboy designed Big Iron around the single purpose of putting data centers in space, which makes it simpler and more efficient to build and fly than a general-purpose vehicle. To further optimize the cost and production speed, many of the rocket’s features serve dual-purposes depending on whether it is on ascent or in orbit. For example, Big Iron’s skin becomes the data center’s radiator; the ammonia propellant becomes the coolant; and the nitrogen pressurizing the rocket’s second stage deploys the satellite’s solar wings.
The key to Cowboy’s design is that rather than deploying a small satellite and being discarded, the upper stage joins Cowboy’s constellation, so every launch grows its compute capacity at a cost competitive price. Once deployed at dawn-dusk orbit, the satellite is 132 meters by 73 meters and can carry five compute racks of NVIDIA Vera Rubin GPUs. The same upper stage will be designed to carry other companies’ payloads, configured to suit each mission.
The stainless steel vehicle with a reusable booster stands 86 meters tall and is designed to carry more than 15,000 kg to sun-synchronous orbit. It is sized to the limit of road transport, which speeds production and keeps capital costs down. The first stage is powered by nine liquid oxygen and methane “Clydesdale” engines, each of which provides 300,000 lbs of thrust. Cowboy selected methane to support reuse, and chose a gas generator engine cycle, a proven architecture, to shorten the path to first flight.
Cowboy has filed an application with the FCC for a 20,000-satellite constellation called Stampede. The company launched its first satellite, Reason-1, on October 1 to demonstrate laser power beaming from orbit to Earth. Reason-2, slated for 2027, will operate GPUs in orbit for commercial and government workloads, processing data where it’s collected and sending results to Earth. Cowboy is targeting its first flight of Big Iron in 2028 and intends to scale its Stampede constellation rapidly thereafter.
