Complete balancing of shaking forces and shaking moments in space mechanisms is the subject of this article. Using real vectors, it presents methods of balancing shaking forces completely in space mechanisms. Force balancing of a mechanism is achieved by attaining a stationary center of the total mass of the mechanism. Design equations for force balancing of the RSSR, RSSP slider-crank and RSRC, CSC, and RCRC screw generators are developed. These mechanisms, their pair inversion mechanisms are force balanced thus establishing general guidelines for force balancing of space mechanisms. It is shown that SC and SRC dyads in space mechanisms also introduce force transmission irregularity in addition to the CRC, CCC, CRP, PRP, PSP, PSC dyads that introduce force transmission irregularity. Space mechanisms with force transmission irregularities are balanced by attaching a force balancing RRR dyad or a linearly moving conterbalancer driven by gear-rack drive, a belt, chain, or rolomite mechanism.