A heat shield is a device that is designed to protect from direct exposure to heat. Heat shields have been used to protect aircraft, spacecraft, missiles, and other high-speed vehicles from severe temperature extremes. They are also used in construction of buildings and automobiles to protect those inside from heat of sun.

Heat shields work by reflecting majority of heat away from their protected object. This is done by absorbing some of heat and then radiating absorbed heat away in form of infrared radiation. The heat shield acts as a barrier between object and extreme temperatures. Without a heat shield, an object exposed to extreme heat or cold temperatures could be damaged or destroyed.

Heat shields typically consist of an internal layer of insulating material such as aluminum, ceramic, or foam. This layer provides primary protection from direct heat and cold. A reflective outer layer is then applied over insulating material. This outer layer can be made of metal, plastic, or a combination of both. The reflection characteristics of this outer layer further reduce temperature on protected object's surface.

Heat shields are often used in combination with other protective measures. For example, a shield may be used in conjunction with insulation to decrease overall temperature of an object. This is especially important in construction of buildings and in automotive industry, where extreme temperatures can cause a great deal of damage.

In space exploration, heat shields are also used to protect a spacecraft from extreme conditions. These shields usually consist of a ceramic or metallic insulation layer and a highly reflective outer layer. This combination helps to keep spacecraft from becoming overly hot or cold during its journey.

Heat shields are an invaluable tool in protecting objects from elements. They are used in a wide range of applications, from automotive industry to space exploration. By reflecting majority of heat away from its protected object, a heat shield helps to ensure that object remains intact.