Global Exploration Roadmap - NASA. A roadmap to expand human presence into the Solar System, with the surface of Mars as a common driving goal.
Life 3.0 - Max Tegmark. Especially relevant are the final chapters applying AI to long-term space exploration.
The Millennial Project: Colonizing the Galaxy in 8 Easy Steps - Marshall Savage. Dated inspirational manifesto for long-term space exploration.
Game Theory of Cooperating With Aliens | Anders Sandberg, Q&A on Cosmology, Inflation & Black Holes | Creon Levit, Adam Brown, Iterate the Game | Stuart Armstrong & Robin Hanson, Space Development: Legal Considerations, Far Future Tech Tree - Foresight Institute. Various seminars on the long-term potential of humanity in space in the light of alien encounters and limited energy.
List of Readings on Space Settlement - NSS. Link list to various near-term and long-term topics for space settlement.
The Meaning of Liberty Beyond Earth - Charles Cockell. Takes the discussion of liberty and democracy into the extraterrestrial environment.
Interplanetary Federalism: Maximising the Chances of Extraterrestrial Peace, Diversity and Liberty - Ian Crawford. On the principle of subsidiarity for space governance.
Elon Musk puts his case for a multi-planetary civilization - Aeon. Long-form article of Elon Musk’s case for space exploration.
A Cosmist Manifesto - Ben Goertzel. Philosophical manifesto on our potential long-term futures in space.
Floating Worlds - Robert McCall. Art focused on space exploration.
Earth Restored - Toby Ord. A selection of beautiful digitally restored photographs of earth.
Kerbal Space Program - Computer game. Create and manage your own space program.