Spacesuits are becoming decidedly less clunky, as illustrated by the futuristic-looking SpaceX suits sported by NASA astronauts Robert Behnken and Douglas Hurley. Way cool.
Check out this NatGeo article on what NASA considers to be "the right stuff" for today's astronauts.
Here are some free resources to learn about the different types of spacesuits and how they've evolved over the years.
Space Exploration Mini-Unit: Seven lessons, with articles and videos, beginning with how to become an astronaut, and culminating in the future of space exploration.
Free Reader:
Train Like an Astronaut: Combine learning about the requirements of space exploration with physical fitness. This site offers videos and free activity guides that explain how exercise and proper nutrition help astronauts maintain and improve important aspects of fitness such as physical strength, endurance, speed, flexibility, balance and coordination.