Calico is the latest engine developed by YJSP's Darcy Program. By combining a forged carbon fiber combustion chamber, a machined silica nozzle, a fiberglass insulator overwrap, and a carbon fiber structural overwrap, Calico achieves excellent thermal performance in a lightweight package. These multi-color composite components also inspired the engine's name, which pays homage to the Darcy Program's cat-related heritage. Calico is fueled by nitrous oxide and isopropyl alcohol and uses a Half Cat inspired scrintle injector.
There have been two Calico engines, Calico I was made in early Spring 2025 and first hot-fired for 3s on April 5th, 2025. This short-duration hot fire validated the ignition sequence and structural integrity of the Calico design. On April 19, 2025, Felicette completed its full-duration static fire (SF2) with Calico I, a 23s hot fire. Following Static Fire 2, the team cut Calico I in half and analyzed its ablative regression rate and ablation profile. Calico I produced 1,800 lbf of thrust with a thrust-to-weight ratio of 106. Calico II was made in early Spring 2026 in preparation for the Felicette Launch. Calico II was our flight engine, with a burn time between 23-27s and 1,800 lbf of thrust based on flight data. On May 15, 2026, Calico II flew to 47,366 feet AGL.
