International space agencies, such as NASA, ESA, and CNSA, continue to push the boundaries of deep space exploration, buoyed by public excitement, scientific ambition, and political motivation. However, the invasion of alien environments warrants an ethical consideration. What are the risks of forward contamination? What are the potential consequences of reverse contamination? How do we avoid a "space race" incentivized by imperialism? What happens next if we do discover life on another planetary body? This course equips students to grapple with such questions in light of the current state of planetary science, world affairs, and the near-term prospects for the commercialization of spaceflight.