8.6 Prediction of component degradation

a. Prediction of component degradation as a function of NIEL shall be performed by one of the following approaches:

1. Calculate the degradation from the total TNID damage predicted considering both elastic and inelastic processes, or

2. By using experimental degradation data for high energy protons, accepted by the customer.

NOTE 1 It is important that the testing conditions are appropriate to the final operating conditions, for example:

• That the component test data used in conjunction with radiation damage parameters to predict degradation are based on tests performed with particle species and energy that are representative of the environment, taking account of the appropriate NIEL conversion data.

• That contamination of the TNID effects data by TID effects are be minimised and taken into account.

• That the particle energies for the tests are sufficient to allow particles to traverse the sensitive part of the device.

• For solar cells, that normal incidence data are converted to represent the expected in-flight distribution (normally assumed isotropic – see ECSS-E-ST-10-04) and cover glass shielding effects.

• That mono-energetic particle tests are permitted provided there is a consistent one-to-one correspondence between the device degradation and TNID, or if the particle energy chosen for testing leads to worst-case degradation of the device.

NOTE 2 For guidelines on predicting component degradation as a function of NIEL, see ECSS-E-HB-10-12 Section 7.3.