It's impossible to name just *one* important scientist in the discoveries of space, as countless individuals have contributed to our understanding of the universe! However, here are a few examples, each representing a different aspect of space exploration:

For the study of celestial bodies:

* Galileo Galilei: Used a telescope to observe the Moon, Jupiter's moons, and the phases of Venus, revolutionizing our understanding of the Solar System.

* Johannes Kepler: Developed the laws of planetary motion, describing how planets orbit the Sun.

* Isaac Newton: Laid the groundwork for our understanding of gravity, explaining the movement of planets and stars.

For space travel:

* Konstantin Tsiolkovsky: Pioneered rocket theory and was the first to envision space travel.

* Robert H. Goddard: Developed the first liquid-fueled rocket, considered the father of modern rocketry.

* Werner von Braun: Led the development of the V-2 rocket, which later laid the foundation for the US space program.

For space exploration:

* Edwin Hubble: Discovered the expansion of the universe and established the distance to other galaxies.

* Neil Armstrong: First human to walk on the Moon, a pivotal moment in human history.

* Sally Ride: First American woman in space, paving the way for future female astronauts.

This is just a small selection of the many brilliant minds who have contributed to our knowledge of space. Their discoveries have changed our understanding of the universe, and continue to inspire us to push the boundaries of human exploration.