8.3 Relevant environments

a. Displacement damage effects shall be analysed for spacecraft and planetary mission systems to be operated within any of the following radiation environments:

1. Trapped proton belts

NOTE For example, terrestrial and other planetary belts, such as Jovian.

2. Solar protons

3. Secondary protons and neutrons

NOTE They can be generated in atmospheric showers in the planetary environment or within the spacecraft or planetary-lander structure.

4. In close proximity to radioactive or nuclear-energy sources

NOTE For example, RTGs generating thermal or fission-spectrum neutrons.

5. Trapped electrons (when considering solar cell degradations and opto-electronic devices).

b. Displacement damage from cosmic ray primary and secondary radiation shall be treated as agreed with the customer.

NOTE It is normally neglected for effects in microelectronics, but it can be important for special or novel scientific instruments and sensors. While NIEL increases with atomic number of the projectile, the reducing fluence of ions with Z means that cosmic-ray heavy ion contribution to TNID is not normally significant.