Thrust chambers are an essential subassembly of liquid propellant rocket engines. This chapter describes chemical rocket thrust chambers and their components, including the topics of ignition and heat transfer. In the thrust chamber liquid propellants are metered, injected, atomized, vaporized, mixed, and burned to form hot reaction gaseous products, which are subsequently accelerated and ejected at supersonic velocities (see Refs. 6–1, 6–2, and 8–1). Chamber assemblies (e.g., Figs. 8–1 and 8–2) comprise one or more injectors, a combustion chamber, a supersonic nozzle, and various mounting provisions. All these parts have to withstand the extreme combustion environments and various forces, including those that transmit thrust to the vehicle. An ignition system must be also present when nonspontaneously ignitable propellants are utilized. Some thrust chamber assemblies also include integrally mounted propellant valves and occasionally thrust vector control devices, as described in Chapter 18. Table 8–1 presents data on five thrust chambers each having different kinds of propellants, cooling methods, injectors, feed systems, thrust levels, and/or nozzle expansions. Some engine parameters are also listed. Several terms used in this table are explained later in this chapter.