Which project is known for discovering the Van Allen Radiation Belts?

The project known for discovering the Van Allen Radiation Belts is The Explorers. This series of missions, particularly the first one, Explorer 1, launched in 1958, was America's initial venture into space research following the Soviet Union's successful Sputnik missions. During its journey, Explorer 1 carried scientific instruments designed to measure cosmic rays and other forms of radiation. The data collected led to the groundbreaking discovery of the Van Allen Radiation Belts, regions of charged particles trapped by Earth's magnetic field, which have critical implications for space weather and satellite operations.

The other projects mentioned, while significant in their own right, did not play a role in the discovery of the Van Allen Radiation Belts. The Apollo Missions primarily focused on lunar exploration and manned spaceflight, the Mars Rover missions are centered around exploring the Martian surface and atmosphere, and the Voyager Probes were launched to study the outer planets and are now in interstellar space. Although all these missions contributed to our understanding of space and planetary science, they were not responsible for identifying the Van Allen Radiation Belts.