The document is a technical paper for Astronautics and Aerospace Engineering Magazine.The copy has handwritten notes that appear to be for revisions. The abstract states "In the early days of rocket propulsion, two primary methods were employed for cooling the walls of thrust chambers. These were uncooled metal chambers where the heat sink capacity of the chamber and nozzle wall materials limited the operating duration, and regeneratively cooled chambers where one of the propellants was circulated in a cooling jacket which constituted the chamber wall. Today, there are at least fourteen different methods with variations for cooling the combustion devices and nozzles of liquid propellant, solid propellant, and/or nuclear rocket propulsion engines. It is the intent of this paper to examine these methods, to describe for each the useful range of operating conditions, as well as present and likely future applications, to define their limitations and associated problems. Emphasis is primarily placed on liquid rocket engines."