QB50 System Requirements Document

4.1.1 SWITCHED Power PinsThe +5, +3V3 and the GND connections are duplicated to provide redundancy in theharness. These have to be controlled by the CubeSat in order to control switching theSU power ON or OFF by SCRIPT command.The CubeSat electrical switch characteristics shall be that BOTH +5V and +3V3 railsshall be switched ON together. The switch ON timing specification is TBD.NOTE: The SU CANNOT switch itself ON or OFF. That can ONLY be done by theCubeSat OBC: either by running a SCRIPT command (to turn ON or OFF), or due to anERROR condition in which case the CubeSat OBC shall ONLY be able toautonomously turn OFF the SU.4.1.2 GroundingThe Science Unit electronics shall be electrically grounded to the SU structure via GND.As some CubeSat teams have suggested that their CubeSat structure may not bemetallic, and that a large area the Solar-panel is also not metallic, the SU to CubeSatGROUND connection shall be made through the SU Connector GND pin. The electricalresistance shall be