Module class 

Impulse classes: the letter in a motor’s designation that bands its total impulse.

Each class tops out at twice the one before it. The National Association of Rocketry’s Standard Motor Codes table gives the upper limits, from 1/8A (0.3125 N·s) through O (40 960 N·s), and its text states the bands as, for example, “5.01 to 10.0 N-sec” for C: a class’s upper limit belongs to it, and the lower limit belongs to the class below.

upper(k) = 1.25 · 2^k N·s,   k = −2 for 1/8A, −1 for 1/4A, 0 for 1/2A, 1 for A, …, 15 for O

1/8A starts at zero. Letters past O (P, Q, …) continue the doubling, as research and amateur rocketry use them; COTS motors stop at O. See docs/physics/motor.md.

Structs

ImpulseClass

A motor’s impulse class, such as 1/4A, C or M.