Heatshield

A heatshield , in the field of the Astronautics, is a device intended to protect part of a Space engine against the kinetic heating.

The term corresponding in English is heat shield .

Presentation

The heatshield is used in particular to protect the objects sent in space (Sonde S, rocket S, space shuttles) from the rise of temperature at the time of the entry of these objects in the atmosphere. Indeed, because of frictions, the temperature can reach thousands of degrees Celsius. However the probes (for example) cannot tolerate these temperatures, and for this reason it is thus necessary to use these shields.
Les heatshields must protect the objects from the high temperatures time that the object is surrounded by plasma.

Composition

An heatshield is consisted a material Isolant, an ablative material or the combination of both.

Fixed and removable shield

According to the applications, the heatshields can be fixed or removable.

For example, the American Space shuttle comprises fixed tiles in ceramic distributed on its lower face and the leading edge of its wings. They are possibly replaced if they are degraded too much at the time of a return on Ground. The accident of the shuttle Columbia came thus from the too important deterioration of part of the wing which could not support the heating of the return. Following this catastrophe a method was developed to repair them in space at the time of exits extravéhiculaires. The major difficulty comes owing to the fact that they are very of different sizes.

Certain planetary probes comprise a removable heatshield which is ejected right before the landing. This ejection makes it possible to reduce the mass which must strike the ground and facilitates braking by a parachute.

Inflatable shield

There exist also inflatable heatshields. They make it possible to gain weight enormously and thus thus to decrease the load with launching.

For the moment this type of shield did not pass the stage of the validation yet. A first test was to be carried out with the launching of the Martian probe March 96, but the latter was destroyed. In October 2005, another demonstrator (IRDT for Innovative Inflatable Re-entry and Descent Technology ), of the European space agency (ESA) was launched by an old Russian ballistic missile, but the demonstrator disappeared without leaving of trace (although it was confirmed that it had separated well from the missile).

Reference

Right French: decree of February 20th, 1995 relating to the terminology of sciences and space technology.

See too

List of the articles relating to astronautics

External bond

'' Successful launch of capsule IRDT '', on the site Flashespace.com
Heatshield of the space shuttle Bourane

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