Question

why do astronauts build radio telescopes and x-ray telescopes, in addition to the optical telescopes with which most people are familiar?

Answer 1

This so that astronauts can study the chemical atmosphere of a planet better. We will know whether the atmosphere will be toxic to our lungs or not. Astronauts need to have a deeper understanding of a planet before going there. For example, before going to the Moon, humans relatively understood what the Moon had no atmosphere, so if you walked in there like you walk down here on Earth, you'd die to shortness of breath. We understood that before landing because these different telescopes help us put light rays not within the visible light spectrum into visible light in images. Hope this helps ;)