RocketPropulsion

A working understanding of chemical propulsion: mass ratio, specific impulse, chamber and nozzle behaviour, staging, and the reasons launch vehicles look the way they do.

The chapter and lesson structure below is real and final. Lesson content is still being written, so nothing here opens yet — and there is no sign-in, no progress and no completion tracking, because none of that is built.

• Comfortable with logarithms

1. 01

   The rocket equation

   Mass ratio, exhaust velocity, and the tyranny of both.

   1. ReadWhere it comes fromConservation of momentum, one integral, and a result that governs everything after it.11m
   2. VisualiseWhy rockets stageCompare single and multi-stage vehicles at the same payload.10m
2. 02

   Chambers and nozzles

   Expansion ratio, over- and under-expansion, sea level versus vacuum.

   1. ReadExpansion ratioWhy a vacuum engine has an enormous bell and a first stage does not.9m
   2. ExploreKeeping it from meltingRegenerative, film and ablative cooling on real engines.8m