A Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind that is captured by and held around a planet by that planet’s magnetic field. The Earth has two such belts and sometimes others may be temporarily created. The discovery of the belts is credited to James Van Allen,
The Van Allen belts are a collection of charged particles, gathered in place by Earth’s magnetic field. They can wax and wane in response to incoming energy from the sun, sometimes swelling up enough to expose satellites in low-Earth orbit to damaging radiation.

-The inner Van Allen Belt extends typically from an altitude of 0.2 to 2 Earth radii (L values of 1 to 3) or 1,000 km (620 mi) to 6,000 km (3,700 mi) above the Earth.

-Earth’s two main belts extend from an altitude of about 500 to 58,000 kilometers above the surface in which region radiation levels vary

The only time humans have crossed through the Van Allen belts was during the Apollo missions to the moon. … NASA restricts the career exposure of a male astronaut the age of the Apollo astronauts to around 300 Rads (coincidentally, an exposure to 300 Rads within one hour is the standard for a lethal dose.)

Radiation, though, is trickier. The surface of the Moon is baldly exposed to cosmic rays and solar flares, and some of that radiation is very hard to stop with shielding. Furthermore, when cosmic rays hit the ground, they produce a dangerous spray of secondary particles right at your feet.

The inner Van Allen Belt extends typically from an altitude of 0.2 to 2 Earth radii (L values of 1 to 3) or 1,000 km (620 mi) to 6,000 km (3,700 mi) above the Earth

The outer Van Allen Belt extends typically from an altitude of three and extending to ten Earth radii (R_E) 13,000 to 60,000 kilometres (8,100 to 37,300 mi) above the Earth’s surface

The outer belt consists mainly of high energy (0.1–10 MeV) electrons trapped by the Earth’s magnetosphere