BS ISO 11221:2011 pdf free download Space systems — Space solar panels — Spacecraft charging induced electrostatic discharge test methods
1 Scope
This International Standard specifies qualification and characterization test methods to simulate plasmainteractions and electrostatic discharges on solar array panels in space. This International Standard isapplicable to solar array panels made of crystalline silicon, gallium arsenide (GaAs) or multi-junction solarcells.This International Standard addresses only surface discharges on solar panels.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.2.1
active gap
gap between solar cells across which a potential difference is present when the solar array power is available
2.2
blow-off
emission of negative charges into space due to an electrostatic discharge
2.3
collisionless plasma
plasma in which the mean free paths of electron-neutral,ion-neutral and coulomb collisions are longer thanthe scale length of interest
NOTEChamber length is an example of a scale length of interest.
2.4
differential charging
spacecraft charging where any two points are charged to different potentials
2.5
differential capacitance
capacitance between any two points in a spacecraft,especially between the insulator surface and thespacecraft body
2.6
differential voltage
potential difference between any two points in a spacecraft during spacecraft charging, especially between theinsulator exterior surface potential and the spacecraft chassis potential
2.7
discharge inception voltage
lowest voltage at which discharges of specified magnitude will recur when a DC voltage is applied betweenany two points in a spacecraft, especially between the insulator surface and the spacecraft body
2.8
electrical breakdown
failure of the insulation properties of a dielectric, resulting in a sudden release of charge with possible damageto the dielectric concerned
2.9
electric propulsion
spacecraft propulsion system in which the thrust is generated by accelerating charged particles that areneutralized before they are ejected in order to produce a jet
2.10
electrostatic discharge
electrical breakdown of dielectric or gas or vacuum gaps, and also of surface interface of dissimilar materials,caused by differential charging of parts of dielectric materials and their interfaces
2.11
gap distance
distance between biased cells or conductors
2.12
glow discharge
gaseous discharge with a surface glow near the cathode surface
NOTE The origin of the ionized gas is mosty ambient neutral gas molecules rather than metal vapour from thecathode surface.
2.13
inverted potential gradientinverted voltage gradient
result of differential charging where the insulating surface or dielectric reaches a positive potential with respectto the neighbouring conducting surface or metal
NOTE
This phenomenon is also known as PDNM(positive dielectric negative metal).
2.14
non-sustained arc
passage of current from an external source through a conductive path that lasts only while the primarydischarge current flows
See Figure 1.
2.15
normal potential gradientnormal voltage gradient
result of differential charging where the insulating surface or dielectric reaches a negative potential withrespect to the neighbouring conducting surface or metal
NOTE This phenomenon is also known as NDPM(negative dielectric positive metal)
2.16
permanent sustained arc
passage of current from an external source through a conductive path that keeps flowing until the externalsource is intentionally shut down
See Figure 1.
NOTE Some permanent sustained arcs may leave a permanent conductive path even after the shut-down.