SPACE ENVIRONMENT: RADIATION AND CHARGED PARTICLES


Radiation and charged particles in space can be harmful to electronics, thus design mitigations should come into play. There are several sources of these elements in space, and we list out three of the most common sources.

Sun Activity 
Sun is basically a giant thermonuclear fusion reactor. Not only does it emit the Ultraviolet (UV) rays that you dread at noon, it also expels plasma at high velocity in  he name of solar wind. There are also these gigantic bursts erupting on the Sun's surface called solar flares.

Sunspots serve as indicator for significant disturbances on the Sun. You can visit this link of you wish to see long-term historical record of solar activity from 1700.

Galactic Cosmic Rays
This is similar to the Sun's solar wind and activities, but coming from distant stars. Cosmic Rays are composed of many different elements such as Hydrogen, Helium and Carbon, and cover a very wide range of energies. They have sufficient energy to penetrate very thick spacecraft shielding.

Van Allen Radiation Belt
As the solar wind bends around the Earth's magnetic field, it stretches out the field lines along with it. This interactions causes some energetic charged particles to get trapped and concentrated within the field lines. This concentration of charged particles is known as the Van Allen Radiation Belt

Now, how do these affect our satellite?

Radiation and charged particles create phenomenon that impact satellites. For now, I'll just enumerate or briefly discuss them here. Some items would require further discussion, especially the single-event phenomenon.
  • Spacecraft charging
    • Results when charges build up on different parts of the satellite
  • Interference and fading
    • This includes satellite communications and radar interference due to electromagnetic radiation
  • False sensor readings
    • These can be attributed to high energy particles causing satellite disorientation and record errors
  • Sputtering
    • This is a process wherein charged particles blasted-off or bombarded to the satellite at high speed
  • Single-event phenomenon
    •  This is due to charged particles that penetrate deep into the satellite and disrupt electronics
  • Surface heating 
    • Due to radiation and emission from the Sun
Ultimately, all those listed above can lead to degradation of and damage to the satellite.

Space Environment
References:
Understanding Space: An Introduction to Astronautics, 2nd edition, Jerry Jon Sellers, McGraw Hill, USA 2004
Spacecraft Systems Engineering, 3rd edition
 

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