Payload fairing

A payload fairing is a nose cone used to protect a spacecraft payload against the impact of dynamic pressure and aerodynamic heating during launch through an atmosphere. An additional function on some flights is to maintain the cleanroom environment for precision instruments.^[1] Once outside the atmosphere the fairing is jettisoned, exposing the payload to outer space.

The standard payload fairing is typically a cone-cylinder combination, due to aerodynamic considerations, although other specialized fairings are in use. The type of fairing which separates into two halves upon jettisoning is called a clamshell fairing by way of analogy to the bifurcating shell of a clam. In some cases the fairing may enclose both the payload and the upper stage of the rocket, such as on Atlas V^[2] and Proton M.^[3]

If the payload is attached both to the booster's core structures and to the fairing, the payload may still be affected by the fairing's bending loads, as well as inertia loads due to vibrations caused by gusts and buffeting.^[4]

In the aerospace industry, a frustum is the fairing between two stages of a multistage rocket (such as the Saturn V), which is shaped like a truncated cone (in geometry, a kind of frustum).