Once dismissed as “too heavy, too complex, not worth it,” the monolithic aerospike rocket engine has had the last laugh. LEAP 71’s 5 kN 5 kN KeroLOX thruster — think of it as rocket science on autopilot: algorithms designed it, 3D printers built it — has survived even more hot-fire testing recently. The weight is on par with bell-nozzle engines, the complexity reduced to a single printed piece, and there's significant efficiency gains, LEAP 71 says. Manufactured at Aconity3D.