How Did Apollo 11 Astronauts Overcome Van Allen’s Radiation Belts During A Flight to the Moon?


The Van Allen belt is the area in which there are charged particles captured by the magnetic field of the planet. In a first approximation, the belt has the shape of a toroid and consists of two parts: the inner belt has a maximum density at an altitude of about 4000 km, and the outer one at an altitude of about 17000 km.

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The belt is inclined with respect to the axis of rotation of the Earth and has a very complex structure, at some point, it approaches the surface of the planet, and somewhere it moves away, its shape and density also depend on solar and even human activity. Between the inner and outer zones, there is a safe zone about 6,000 km wide.

Apollo 11 Astronauts Overcome Van Allen's Radiation Belts
Apollo 11 Astronauts Overcome Van Allen’s Radiation Belts

The radiation level in the Van Allen belt is really high, but not as much as the supporters of the lunar conspiracy draw. If you launch a person to fly directly in the belt, he will receive a dangerous dose of 1 sievert in a few days, and a lethal dose of 5 Sv for a couple of weeks of flight, the exact time depends on the particular orbit.

The flight paths of all Apollos, except for the 14th, circumvented the internal radiation belt and crossed only the external one in the thinnest areas and at the highest possible speeds. For astronauts flying to the moon, crossing the Van Allen belt took a matter of hours: about 3.5 hours when flying to the moon and about 2.5 hours on the way back, in addition, the Apollo had radiation protection, only 25 mm aluminum, and the module was additionally protected with steel, with a thickness of 18 to 69 mm.

Apollo 11 command module
Apollo 11 command module

Thus, it was possible to minimize the damage from radiation during the passage of the belt, the astronauts received the main dose during the flight outside the Earth’s magnetic field. Depending on the mission, the dose absorbed by the astronauts varied from 1.6 to 11.4 mSv, which is significantly less than the standard dose of 50 mSv per year established for people working with radiation and which is considered non-hazardous.

Astronauts, who gained 11.4 mSv during a flight to the Moon, after living for a year on Earth in ordinary conditions, would not even come close to 50 mSv. Therefore, overcoming the Van Allen belt is completely safe and even flying to the Moon and back does not cause much damage to the body in terms of radiation.



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