Stasis for interstellar space travel. “Freezing” people into a low-activity biological state. IRL medical developments.
Space junk in near-earth orbit. That time a paint chipped cracked a window on the ISS (don’t worry, the ISS is fine). Comet tails and variously-sized chunks of ice as impactors.
Atmospheric density vs interstellar velocities. The benefits of landing on a planet with atmosphere vs a planet without. It’s hard without! Realizing having an atmosphere to slow down in can be a blessing if the ship can handle the temperatures due to atmospheric compression under/around the vessel.
Trinary systems and the chance for stable planetary orbits. Proxima Centauri. Globular star clusters as alternative for “all light all the time.”
Predators on the “cicada cycle.” How the ecology of this world appears or does not appear to support this cycle. Slowly-heating stars and the shifting “goldilocks” zone.
Eyeshine! Light amplification or translation from outside of our cone of EM reception. Night vision. Replacing eyeballs with robust cameras. Ghost in the Shell and X-ray vision.
Evolving bioluminescence as a food-collection mechanism vs keeping away the flying death-machines.