In this lesson from Yale's Rocket Science for Everyone, astronomer Marla Geha explains multistage rocket design as an engineering solution to the limits imposed by the rocket equation covered in the prior lesson. The lecture describes how shedding spent stages during flight allows a rocket to reach higher speeds than a single stage vehicle of the same total fuel mass could achieve. The lesson connects the mathematics of the rocket equation to real design decisions in launch vehicle engineering, completing the course's core propulsion sequence before the material moves toward specific satellite launch case studies.