Status: Hardware. Date: 2000-2004. Thrust: 8.00 kN (1,798 lbf).
XCOR's largest engine in active development, designated XR4K5, was an 8,000-newton engine that was pump-fed, LOX/kerosene regeneratively cooled with fuel. This engine may be used to power the prototype Xerus vehicle for initial flight testing, but XCOR has not yet decided on this approach.
Propellant Formulation: Lox/RP-1.