Engine Model: Rotary Rocket. Designer: XCOR. Developed in: 2000-2004. Application: First stages. Propellants: Lox/Kerosene. Thrust(vac): 22.250 kN (5,002 lbf). Chambers: 1. Country: USA. Status: Developed in 1990's. In April 2002, XCOR acquired selected intellectual property assets of the former Rotary Rocket Company. These assets included a 22,250-newton LOX/kerosene engine developed and tested by the company as well as hydrogen peroxide engine technology.