Space Radiation – Interplanetary Radiation Belts

Written by: Megan Wetegrove In this post, planetary radiation belts are introduced, with special emphasis on Earth’s planetary radiation belts – the Van Allen Belts. Requirements for Planetary Radiation Belts In order for a radiation belt to form around a planet, the planet must have a magnetic field. This magnetic field is able to deflect charged particles that are traveling in the planet’s direction. The area around the planet in which the magnetic field is able to control particles is called the magnetosphere. When a magnetosphere is present around a planet, most space radiation directed at the planet is deflected. Below is an image of Earth’s magnetic field deflecting charged particles from the Sun. Image Source: http://en.wikipedia.org/wiki/File:Magnetosphere_rendition.jpg A planet’s magnetic field is able to offer the planet a great amount of protection from charged particles. At the same time, the presence of a magnetic field gives rise to planetary radiation belts on account of the field trapping a number of charged particles along magnetic field lines. Consequently, these particles form donut-shaped ‘belts’ around the planet. Currently, Mercury, Earth, Jupiter, Saturn, Uranus, and Neptune are surrounded by trapped radiation. Venus and Mars do not have magnetic fields; thus, these planets are not able to trap charged particles. The Van Allen Belts The Van Allen belts are two planetary radiation belts surrounding Earth. The belts are donut-shaped crescents that do not extend as far as Earth’s poles. The inner belt, extending from approximately 400 km to 18,400 km (measured from the equator) consists mainly of electrons with maximum energy of 10 MeV. Electron fluxes with energies greater than 2 MeV peak...

Introduction to Space Radiation

Written by: Megan Wetegrove The existence of space radiation plays an important part in planning space missions within low Earth orbit (LEO) and beyond. Space radiation has the potential to negatively impact several aspects of space missions, whether manned or unmanned, within in LEO or farther into space. Radiation can be detrimental to the health of astronauts, increasing the risk of cancer and genetic mutations, and to electronic equipment functionality, decreasing the lifetime of important electronic equipment and/or resulting in total electronic failure. As a result, protection against space radiation is vital to the success of any space mission, especially missions outside of Earth’s magnetosphere. Beyond the magnetosphere, less protection from space radiation is afforded to astronauts and electronic equipment. In order to achieve mission success, become familiar with the three space radiation sources, and determine the extent that space radiation will affect the mission. The three types of space radiation include Trapped charged particles along the field lines of a planet’s magnetic field (radiation belts) Particles from the Sun’s heliosphere released during solar particle events (SPE) Galactic cosmic radiation (GCR) from outside of the solar system In this series of posts on natural space radiation, each type of space radiation will be examined. Once each type has been discussed, a series of articles on how to protect astronauts and electronic equipment from space radiation will follow. Megan WetegroveMore...