The Van Allen Belts | Its Effect On Astronauts

There is an invisible magnetic force field surrounding our planet, protecting us from harmful solar winds that could annihilate Earth. But, this protective blanket is also a swirling ring full of deadly radiation and to leave Earth’s atmosphere astronauts have to pass through it.

The Van Allen belts are rings of energetically charged particles that have been captured by Earth’s magnetic field. They got their name from the Physicist named James Van Allen. Back in the 1950s, Van Allen launched a rockoon, a rocket lifted by a balloon above the atmosphere and it detected the first hint of radiation at higher altitudes. Then Explorer 1, the first American satellite to orbit Earth, launched on January 13, 1958, confirmed that Earth’s magnetosphere was trapping the subatomic particles.

The Van Allen belts were the first major scientific discovery of early Space Age and they posed a serious challenge for space travel. High-speed subatomic particles can tear through DNA, increasing the risk of cancer and other desires. So sending astronauts through these particles is not ideal and even though they are flying in a shielded spacecraft, doses of radiation can still seep through. But there is no way around the Van Allen belts. In order to reach space, astronauts have to fly through them.

There are Two belts, First the inner belt which is comprised of protons and then the outer belt which has mostly high energy-electrons. One solution, proposed by Mr Van Allen himself, suggested detonating a nuclear boom in the inner belt to clear out some of the subatomic particles. Van Allen’s plan never executed, but in 1962, the United States did carry out a nuclear test in space, dubbed StarFish Prime. They wanted to see if detonating a 1.4 megaton boom in low-Earth orbit could augment and expand the Van Allen Belts, but the explosion actually ends up adding more radiation around our planet.

So, for the Apollo mission, NASA  had to create a radiation barrier within the spacecraft and figure out a trajectory that avoided the thickest, most radioactive parts of the belts while travelling as fast as possible. Scientists determined that if the speed of the Apollo spacecraft was about 25,000 kilometres per hour, it would take a spacecraft about 52.8 minutes to pass through the belts. Based on that information scientists found that the radiation doses received during that amount of time would be, at most, 11.4 rads and that’s without the protection of a spacecraft. Since a lethal radiation dosage for a human is 300 rads in one hour, so NASA deemed the missions a go. After all that, it turned out that during the Apollo missions the average radiation doses on the skin of the astronauts came out to be 0.38 rad which is about the same radiation you would receive by getting two CT scans of your head.

So while the Van Allen belts are lethal, they could really only kill an astronaut if they were to spend several days in their radioactive vicinity and despite the challenges the belts create when leaving Earth, we should actually be thanking them for protecting life on our planet from utter annihilation.

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