Near-Earth Hazards
Definition
Near-Earth space is not completely empty, but filled with several classes of charged particles that get trapped by the Earth’s magnetic field. These particles form distinct fields in 3-dimensional space around the Earth (a.k.a. Van Allen radiation belts) that vary in location and density over time as the Earth’s magnetic field interacts with the Solar wind.
What happens?
When satellites pass through these fields of charged particles, their payloads are exposed to ionizing radiation that can cause temporary failure or permanent damage to sensitive electronic components.
Traditionally, a careful analysis of the radiation exposure profile of the satellite’s intended orbit(s) is carried out before launch and the satellite payload is build with sufficient radiation shielding (e.g., carbon fiber, aluminum) to reduce the probability of radiation-induced electronic component failures below a target threshold. Various techniques for more robust circuit design and software architectures have also been proposed.
Takeaways
The key takeaway for LSN research is to acknowledge that different orbits have different baseline cost profiles. Orbits that encounter more radiation over their lifetimes require more expensive satellite payloads with extra shielding. Orbits that encounter less radiation can get by with cheaper payloads with less shielding.