YJSP Calico

YJSP Calico is an ablatively cooled nitrous-oxide/isopropanol liquid rocket engine developed by the Yellow Jacket Space Program’s Darcy team. It combines a forged-carbon combustion chamber, machined silica nozzle, fibreglass insulating overwrap and carbon-fibre structural overwrap with a Half Cat-inspired scrintle injector. Calico I underwent an initial three-second hot-fire on 5 April 2025 and a 23-second static firing on 19 April before being sectioned for ablation inspection. The second built engine, Calico II, powered Felicette’s 15 May 2026 flight to a reported 47,366 feet AGL. The team reports approximately 1,800 lbf thrust and a 23–27-second burn from flight data.