A variety of research projects are being pursued involving the dynamics and control of large space platforms made up of lattice-type truss structures. A method involving finite element modeling of an equivalent continuum formulation based on matching the strain energy and kinetic energy is developed. The method is shown to give modal results consistent with those obtained using detailed finite element modeling of the space lattice structure, even for structures with fairly small numbers of repetitions of an identical unit cell. Feedback controllers designed using reduced system models derived from these modal results using modal cost analysis are shown to perform as well as controllers designed using the detailed analysis results.