The first person to use radio waves in space was Karl Jansky, an American physicist and engineer. In the 1930s, Jansky was working for Bell Telephone Laboratories and investigating sources of radio interference. As part of his research, he built a large directional antenna system to detect and locate the sources of radio static.
In 1932, Jansky pointed his antenna at the sky and made a groundbreaking discovery. He detected an unexpected hissing or static-like signal coming from the Milky Way galaxy. Jansky realized that he was picking up radio waves originating from space, specifically from the center of the Milky Way.
Jansky's discovery marked the birth of radio astronomy, which is the study of celestial objects using radio waves. His work laid the foundation for further advancements in the field, and his findings opened up a new window to observe and understand the universe beyond what could be seen with traditional optical telescopes.