A state of readiness for immediate action: “Your proposal has been approved, so it's all systems go.” This phrase originated in the 1960s during the heyday of space flight and referred to the launching of missiles and other space vehicles.
all systems go
Everything is ready for proceeding, as in They've rented a hall and lined up the speakers, so it's all systems go for the rally. Originating in the late 1960s with reference to launching space missiles and vehicles, this expression has been transferred to general use.