Deep Field

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Deep Field
29 September 2026 2518 stories tracked

Glossary · Launch & Flight

Max-Q

The moment of peak aerodynamic pressure on an ascending rocket.

A rocket accelerates while the air thins, and the product of the two — dynamic pressure — peaks about a minute in, typically around 11–13 km. That is the point of greatest structural stress, and many vehicles throttle down to get through it, which is the "throttling up" call you hear afterwards. Above max-Q the air is thin enough that the vehicle can push as hard as it likes. It is one of the few named moments in an ascent that corresponds to a genuine physical hazard rather than a programme milestone, which is why launch commentary always calls it out.

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. Staging Throwing away the empty part of the rocket so you stop accelerating it. Thrust-to-weight ratio Whether the rocket can lift itself, expressed as a number that must exceed one.

Questions

What is Max-Q?

The moment of peak aerodynamic pressure on an ascending rocket.

Why does it matter?

Above max-Q the air is thin enough that the vehicle can push as hard as it likes. It is one of the few named moments in an ascent that corresponds to a genuine physical hazard rather than a programme milestone, which is why launch commentary always calls it out.

Written and computed by . Corrections and errors to hello@cantinalabs.dev.