J.3.1 Impact risk analysis procedure

For a given surface area and exposure duration the total number of impacts N is obtained from the impact flux by multiplication with the total exposed surface area and exposure duration.

From the number of impacts, N, the probability of exactly n impacts occurring in the corresponding time interval is determined by Poisson statistics:

(J-1)

The probability for no impacts, P₀ is given by:

(J-2)

For values of N << 1, the probability Q for at least one impact (Q = 1 - P₀) is nearly equal to N:

(J-3)