In this lesson from Yale's Rocket Science for Everyone, astronomer Marla Geha examines the varied motivations behind satellite missions through three case studies: Sputnik, the first artificial satellite, and the more recent SWOT and UVEX missions. The lecture uses these examples to illustrate how satellite design and launch decisions follow from a mission's scientific or strategic goals. Drawing on the course's earlier lessons on orbital mechanics and rocket propulsion, this lesson applies those concepts to real historical and contemporary missions, showing students how the abstract physics covered earlier plays out in actual spaceflight programs.