arXiv:2605.23481v2 Announce Type: replace-cross Abstract: Distributed space antennas using electromagnetic formation flight (EMFF) are a promising architecture for large-aperture, long-life space communication systems. Their system design, however, is governed by coupled constraints on antenna performance, satellite mass, power generation, coil geometry, and formation-keeping power. This paper proposes a system-level design framework for EMFF-based distributed space antennas. It links phased-array requirements with satellite and formation-system sizing for a static grid under a fixed total system mass. Before system-level optimization, distributed-control simulations are used to derive a control index that quantifies the formation-maintenance requirement. This index is integrated into an optimization problem with a user-defined objective and sizing, power, coil, and sidelobe-envelope constraints. Parametric case studies examine the margin magnetic moment, prescribed transmit power, and large inter-satellite spacing. Results show that increasing system mass improves footprint reduction or effective isotropic radiated power only while satellite-level design headroom remains. In direct-to-device cases with 0.15-m spacing, generated power and coil-geometry constraints dominate the feasible aperture. In the 0.30-m large-spacing case, the required coil burden can exceed satellite-level mass, size, and power capacities, making the design infeasible despite favorable communication performance. Higher-fidelity simulations of representative designs evaluate formation maintenance under nonlinear $J_2$ dynamics and antenna gain with mutual coupling, further supporting the framework's usefulness for preliminary design. The proposed framework enables the design and evaluation of feasible static grid-based EMFF distributed antennas under coupled antenna, satellite, and control constraints.