An aerospace vehicle consists of one or many compartments enclosed by doors that need to be locked against interface seal loads and external loads and need to be opened when required, i.e. during deploying of missiles in case of a fighter aircraft or payload in case of a Reusable Launch Vehicle. The objective of this paper is to synthesize a latch mechanism that can capture doors within particular range and close them against seal loads with minimum input motor torque requirement and positively lock them. So, a mathematical model is developed in MATLAB that can evaluate input torque requirement at discrete angular positions of doors with respect to given geometrical parameters and seal properties. Optimization studies are carried out using the model and the combination of parameters that result in least peak input torque is obtained. Dynamic analysis of the optimal latch mechanism is carried out and results are found comparable. In the literature currently available on synthesis of four bar mechanisms, links are assumed as lines and their structural dimensions (except link lengths) are not considered. The novelty of this work is that a methodology is described for synthesis of straddle mounted pin joint four bar mechanism where structural dimensions of links like pin hub radius and link width are also considered so that interference doesn’t occur between moving links. Also, along with four bar optimization, hook profile optimization is described here.