The temperature requirements of instruments and onboard equipment are the main factor in the design of the thermal control system. The objective of TCS is to keep all working instruments within the allowable temperature range. Most of all on-board electronic instruments, such as cameras, data collection devices, batteries, etc. of the house, have a fixed operating temperature range. Maintaining these instruments in their operating temperature range is of vital importance for each mission. Some examples of temperature ranges include:.

Covering

Coating (in English, thermal coating or simply coating) is the simplest and cheapest TCS technique. Coating is the most sophisticated paint or chemical applied to spacecraft surfaces to lower or increase heat transfer. The characteristic of the type of coating depends on its absorption capacity, emissivity, transparency "Transparency (physical)") and reflectivity. The main disadvantage of the coating is that it degrades quickly due to the operating environment.

Multi-layer insulation (MLI)

Multi-layer insulation (MLI) is the most common passive thermal control element used in spacecraft. MLI prevents both heat losses from the environment and excessive heating of the environment. Spacecraft components, such as fuel tanks, propellant lines, batteries and solid rocket motors, are also covered with MLI blankets to maintain ideal operating temperatures. The MLI consists of an outer cover layer, an inner layer and an inner cover layer. The outer shell layer needs to be opaque to sunlight as it generates a small amount of particulate contaminants and is able to survive the environment and temperature to which the spacecraft is also exposed. Some common materials that the outer layer uses are fiberglass, cloth rag impregnated with PTFE Teflon, PVF reinforced with Nomex and bonded with polyester adhesive and FEP Teflon. The general requirement of the inner layer is that it needs to have low emissivity. The most common material this layer uses is aluminized Mylar, which is on one or both sides. The inner layers are usually thin compared to the outer layer to save weight and are also perforated to help vent trapped air during launch. The inner shell facing the spacecraft and hardware is used to protect the thin inner layers. The interior covers are usually not aluminized, in order to prevent electrical short circuits. Some of the materials used in internal surplus nets are Dacron nets and Normex nets. Mylar is not used due to flammability concerns. MLI blankets are an important element of the thermal control system.

Grilles

Louvers are active thermal control elements that are used in many different ways. Most commonly placed over external radiators, grilles can also be used to control heat transfer between the internal surfaces of the spacecraft, or placed in openings in the walls of the spacecraft. A grille in its fully open state can reject six times more heat than in its fully closed state, with no power needed to operate it. The most commonly used grille is the bimetallic, spring-loaded grille, that is, a rectangular leaf grille, also known as a blind Venetian grille. Louver radiator grille assemblies consist of five main elements: base plate, blades, actuators, sensing elements and structural elements.

Heaters

Heaters are used in thermal control design to protect components in cold ambient conditions or to compensate for heat that is not dissipated. Heaters are used with solid-state thermostats or controllers to provide exact temperature control of a particular component. Heaters are also used to warm components to minimum operating temperatures before the components are turned on.

The most common type of heater used on spacecraft is the patch heater, which consists of an electrical resistance element sandwiched between two sheets of flexible, electrically insulating material, such as Kapton. The patch heater may contain a single circuit or multiple circuits, depending on whether or not redundancy is required within it. Another type of heater, the cartridge heater, is often used in blocks of material or high temperature components to heat, such as propellants. This heater consists of a spiral resistor enclosed in a cylindrical metal case. Typically a hole is drilled in the component being heated and the cartridge is encapsulated in the hole. Cartridge heaters are generally a quarter inch or less in diameter and up to a few inches long.

Another type of heater used on spacecraft is radioisotope heating units, also known as RHUs. RHUs are used to travel to the outer plants of Jupiter, due to the low solar radiation, which means that energy is generated from very valuable solar panels. These heaters do not require electrical power from the spacecraft and provide direct heat where you need it. At the center of each RHU is a radioactive material that decays to provide heat, the most commonly used material being plutonium dioxide. A single RHU weighs only 42 grams and can fit into a 26mm diameter and 32mm long cylindrical case. Each unit also generates 1 W of heat in the encapsulation, however the heat generation rate decreases over time. A total of 117 RHUs were used on the Cassini mission.

Radiators

Radiators are surfaces with high emissivity in the infrared spectrum to maximize heat rejection and low absorptivity in the visible spectrum to limit the retention of solar radiation. Most radiators dissipate between 100 and 350 W/m² of heat generated internally by electronic equipment. The weight of the radiators varies from zero, when an existing structural panel is used as a radiator, to 12 kg/m² for a heavy deployable radiator with supporting structure.

heat pipes

Heat pipes use a two-phase closed-flow liquid cycle with an evaporator and a condenser to transport relatively large amounts of heat from one location to another without requiring electrical power.

The most important event in the field of space thermal control is the International Conference on Environmental Systems", organized each year by the American Institute of Aeronautics and Astronautics.

The temperature requirements of instruments and onboard equipment are the main factor in the design of the thermal control system. The objective of TCS is to keep all working instruments within the allowable temperature range. Most of all on-board electronic instruments, such as cameras, data collection devices, batteries, etc. of the house, have a fixed operating temperature range. Maintaining these instruments in their operating temperature range is of vital importance for each mission. Some examples of temperature ranges include:.

Covering

Coating (in English, thermal coating or simply coating) is the simplest and cheapest TCS technique. Coating is the most sophisticated paint or chemical applied to spacecraft surfaces to lower or increase heat transfer. The characteristic of the type of coating depends on its absorption capacity, emissivity, transparency "Transparency (physical)") and reflectivity. The main disadvantage of the coating is that it degrades quickly due to the operating environment.

Multi-layer insulation (MLI)

Multi-layer insulation (MLI) is the most common passive thermal control element used in spacecraft. MLI prevents both heat losses from the environment and excessive heating of the environment. Spacecraft components, such as fuel tanks, propellant lines, batteries and solid rocket motors, are also covered with MLI blankets to maintain ideal operating temperatures. The MLI consists of an outer cover layer, an inner layer and an inner cover layer. The outer shell layer needs to be opaque to sunlight as it generates a small amount of particulate contaminants and is able to survive the environment and temperature to which the spacecraft is also exposed. Some common materials that the outer layer uses are fiberglass, cloth rag impregnated with PTFE Teflon, PVF reinforced with Nomex and bonded with polyester adhesive and FEP Teflon. The general requirement of the inner layer is that it needs to have low emissivity. The most common material this layer uses is aluminized Mylar, which is on one or both sides. The inner layers are usually thin compared to the outer layer to save weight and are also perforated to help vent trapped air during launch. The inner shell facing the spacecraft and hardware is used to protect the thin inner layers. The interior covers are usually not aluminized, in order to prevent electrical short circuits. Some of the materials used in internal surplus nets are Dacron nets and Normex nets. Mylar is not used due to flammability concerns. MLI blankets are an important element of the thermal control system.

Grilles

Louvers are active thermal control elements that are used in many different ways. Most commonly placed over external radiators, grilles can also be used to control heat transfer between the internal surfaces of the spacecraft, or placed in openings in the walls of the spacecraft. A grille in its fully open state can reject six times more heat than in its fully closed state, with no power needed to operate it. The most commonly used grille is the bimetallic, spring-loaded grille, that is, a rectangular leaf grille, also known as a blind Venetian grille. Louver radiator grille assemblies consist of five main elements: base plate, blades, actuators, sensing elements and structural elements.

Heaters

Heaters are used in thermal control design to protect components in cold ambient conditions or to compensate for heat that is not dissipated. Heaters are used with solid-state thermostats or controllers to provide exact temperature control of a particular component. Heaters are also used to warm components to minimum operating temperatures before the components are turned on.

The most common type of heater used on spacecraft is the patch heater, which consists of an electrical resistance element sandwiched between two sheets of flexible, electrically insulating material, such as Kapton. The patch heater may contain a single circuit or multiple circuits, depending on whether or not redundancy is required within it. Another type of heater, the cartridge heater, is often used in blocks of material or high temperature components to heat, such as propellants. This heater consists of a spiral resistor enclosed in a cylindrical metal case. Typically a hole is drilled in the component being heated and the cartridge is encapsulated in the hole. Cartridge heaters are generally a quarter inch or less in diameter and up to a few inches long.

Another type of heater used on spacecraft is radioisotope heating units, also known as RHUs. RHUs are used to travel to the outer plants of Jupiter, due to the low solar radiation, which means that energy is generated from very valuable solar panels. These heaters do not require electrical power from the spacecraft and provide direct heat where you need it. At the center of each RHU is a radioactive material that decays to provide heat, the most commonly used material being plutonium dioxide. A single RHU weighs only 42 grams and can fit into a 26mm diameter and 32mm long cylindrical case. Each unit also generates 1 W of heat in the encapsulation, however the heat generation rate decreases over time. A total of 117 RHUs were used on the Cassini mission.

Radiators

Radiators are surfaces with high emissivity in the infrared spectrum to maximize heat rejection and low absorptivity in the visible spectrum to limit the retention of solar radiation. Most radiators dissipate between 100 and 350 W/m² of heat generated internally by electronic equipment. The weight of the radiators varies from zero, when an existing structural panel is used as a radiator, to 12 kg/m² for a heavy deployable radiator with supporting structure.

heat pipes

Heat pipes use a two-phase closed-flow liquid cycle with an evaporator and a condenser to transport relatively large amounts of heat from one location to another without requiring electrical power.

The most important event in the field of space thermal control is the International Conference on Environmental Systems", organized each year by the American Institute of Aeronautics and Astronautics.