Trim Condition

Definition

A Trim Condition refers to a flight state where all forces and moments are in balance without control surface deflection or with minimal control input. In spacecraft flight dynamics, the trim condition corresponds to the condition where the sum of external moments — including aerodynamic moments, thrust vector moments, and gravity gradient moments — equals zero. It serves as the foundation for attitude control system design and flight performance analysis. For re-entry vehicles and lifting bodies, the trim angle of attack is a critical design parameter.

Note: This entry is being developed.