Science Capsules

Mars colonization faces severe barriers, from radiation exposure in deep space and on the surface to the difficulty of extracting and using local resources at planetary scale. The Moon offers a nearer, more practical proving ground where shielding, resource use, habitation, and manufacturing can be developed under conditions that still demand real spacefaring capability. A moon-first strategy builds the infrastructure and operational experience needed to make later Mars missions safer, more sustainable, and more achievable.

The claim that the Great Wall is visible from orbit survives in textbooks and trivia nights despite astronauts saying otherwise. The arguments here approach the myth from different angles: the physics of human eyesight, firsthand astronaut testimony, the role of cameras and optical aids, and why comfortable falsehoods outlive clear corrections. It becomes a lesson in how to test what everyone knows.