A robust and growing commercial space sector is moving ahead at warp speed. While the industry today primarily offers satellite and launch services, tomorrow will bring manufacturing, research and development, resource extraction, and space tourism. What do these developments mean for the earth’s biosphere, as well as for the environments of other celestial bodies finally within humanity’s reach? This is the role of planetary protection, the principle of safeguarding both terrestrial and extraterrestrial environments from humanity’s propensity for introducing pollution into any habitat.