NASA
Payload fairing
The nose cone that protects the satellite through the atmosphere and is then discarded.
The fairing is the aerodynamic shell over the payload, and it comes off as soon as the air is thin enough for the spacecraft to survive unprotected — usually around three minutes in and 100 km up. Its diameter, not the rocket's thrust, is what limits many payloads: a telescope mirror has to fold to fit inside one, which is why Webb had eighteen hexagonal segments rather than a single disc. Fairing halves are large, expensive composite structures, and several operators now recover and reuse them from the sea.
Where it has come up lately
Related terms
Delta-v
The currency of spaceflight: how much you can change your velocity, in metres per second.
NET (no earlier than)
A launch date that is a lower bound, not a promise.
Max-Q
The moment of peak aerodynamic pressure on an ascending rocket.
Staging
Throwing away the empty part of the rocket so you stop accelerating it.
Questions
What is Payload fairing?
The nose cone that protects the satellite through the atmosphere and is then discarded.
Why does it matter?
Its diameter, not the rocket's thrust, is what limits many payloads: a telescope mirror has to fold to fit inside one, which is why Webb had eighteen hexagonal segments rather than a single disc. Fairing halves are large, expensive composite structures, and several operators now recover and reuse them from the sea.