How To Terraform Venus, Asteroid Mining: Unlimited Resources from Space, How to Build A Dysonsphere, How To Build A Marsbase, How to Build A Moonbase, Stellar Engines - Kurzgesagt. Explainer videos on our long-term future in space.
ESA Space Technology Tree - J. Westman. Classifies the technological expertise available in ESA for space technology.
TechPort - NASA. Portfolio of active and completed technology projects.
Cosmic Vision - ESA. Europe’s Plan for Space Science 2015 - 2025.
Statites - Space.stackexchange. On the possibility of statites, satellites which are stationary above a planet without being in orbit.