Apollo command and service moduleThe Apollo command and service module (CSM) was one of two principal components of the United States Apollo spacecraft, used for the Apollo program, which landed astronauts on the Moon between 1969 and 1972. The CSM functioned as a mother ship, which carried a crew of three astronauts and the second Apollo spacecraft, the Apollo Lunar Module, to lunar orbit, and brought the astronauts back to Earth.
Rolling (metalworking)In metalworking, rolling is a metal forming process in which metal stock is passed through one or more pairs of rolls to reduce the thickness, to make the thickness uniform, and/or to impart a desired mechanical property. The concept is similar to the rolling of dough. Rolling is classified according to the temperature of the metal rolled. If the temperature of the metal is above its recrystallization temperature, then the process is known as hot rolling.
Bar stockBar stock, also (colloquially) known as blank, slug or billet, is a common form of raw purified metal, used by industry to manufacture metal parts and products. Bar stock is available in a variety of extrusion shapes and lengths. The most common shapes are round (circular cross-section), rectangular, square and hexagonal. A bar is characterised by an "enclosed invariant convex cross-section", meaning that pipes, angle stock and objects with varying diameter are not considered bar stock.
BellfoundingBellfounding is the casting and tuning of large bronze bells in a foundry for use such as in churches, clock towers and public buildings, either to signify the time or an event, or as a musical carillon or chime. Large bells are made by casting bell metal in moulds designed for their intended musical pitches. Further fine tuning is then performed using a lathe to shave metal from the bell to produce a distinctive bell tone by sounding the correct musical harmonics.
ForgingForging is a manufacturing process involving the shaping of metal using localized compressive forces. The blows are delivered with a hammer (often a power hammer) or a die. Forging is often classified according to the temperature at which it is performed: cold forging (a type of cold working), warm forging, or hot forging (a type of hot working). For the latter two, the metal is heated, usually in a forge. Forged parts can range in weight from less than a kilogram to hundreds of metric tons.
MetalA metal (from Ancient Greek μέταλλον métallon 'mine, quarry, metal') is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically ductile (can be drawn into wires) and malleable (they can be hammered into thin sheets). These properties are the result of the metallic bond between the atoms or molecules of the metal. A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polymeric sulfur nitride.
Yield (engineering)In materials science and engineering, the yield point is the point on a stress-strain curve that indicates the limit of elastic behavior and the beginning of plastic behavior. Below the yield point, a material will deform elastically and will return to its original shape when the applied stress is removed. Once the yield point is passed, some fraction of the deformation will be permanent and non-reversible and is known as plastic deformation.
Rocket propellantRocket propellant is the reaction mass of a rocket. This reaction mass is ejected at the highest achievable velocity from a rocket engine to produce thrust. The energy required can either come from the propellants themselves, as with a chemical rocket, or from an external source, as with ion engines. Rockets create thrust by expelling mass rear-ward, at high velocity. The thrust produced can be calculated by multiplying the mass flow rate of the propellants by their exhaust velocity relative to the rocket (specific impulse).
Amorphous solidIn condensed matter physics and materials science, an amorphous solid (or non-crystalline solid) is a solid that lacks the long-range order that is characteristic of a crystal. The terms "glass" and "glassy solid" are sometimes used synonymously with amorphous solid; however, these terms refer specifically to amorphous materials that undergo a glass transition. Examples of amorphous solids include glasses, metallic glasses, and certain types of plastics and polymers. The term comes from the Greek a ("without"), and morphé ("shape, form").
ExtrusionExtrusion is a process used to create objects of a fixed cross-sectional profile by pushing material through a die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex cross-sections; and to work materials that are brittle, because the material encounters only compressive and shear stresses. It also creates excellent surface finish and gives considerable freedom of form in the design process.
