a. Surface materials shall be conductive to reduce differential charging over the spacecraft surface to a value to be agreed with the customer.
NOTE This value is mission dependent, and normally about 10 V.
b. Secondary electron and photo-electron currents originating from surfaces shall be kept to a fraction of the expected natural electron flux at detector exposed surfaces, agreed with the customer.
NOTE This fraction is mission dependent and is normally 10 %.
c. The floating potential of the particle detector entrance and of neighbouring surfaces shall be analysed.
d. The effect of elevated voltage systems and of the spacecraft motion through the ambient magnetic field shall be analysed.
NOTE An example is for solar array.
e. To mitigate positive or negative potential, an ion or respectively electron emitter shall be used with particle energy emission higher than the maximum expected floating potential to be mitigated.
NOTE 1 Plasma contactors are generally avoided on scientific spacecraft because of the large scale disturbance they induce on scientific measurements.
NOTE 2 In practice the reduction of photo-electron and secondary electron emission is often achievable by active potential control techniques only.