Science news this week: NASA announces nuclear rocket, space reproduction proves difficult, and why weed gives people the munchies - Live Science

1. Science news this week: NASA announces nuclear rocket, space reproduction proves difficult, and why weed gives people the munchies  Live Science
2. Simulated microgravity alters sperm navigation, fertilization and embryo development in mammals  Nature
3. Astronauts may struggle to reproduce in outer space, study suggests — what does that mean for the future of space colonization?  Live Science
4. Lost in space: Sperm struggles to navigate during weightless sex  Medical Xpress
5. Can humans have babies in space? It may be harder than expected  Space