AEROSPACE PLANE ASCENDING TRAJECTORIES WITH HEAT CONSIDERATION

This is a study of performance and control for transatmospheric (TAV) aerospace planes, that use air-breathing propulsion. The study is stru ctured in two parts and considers the heat load near the stagnation po int. The first part is analytical and consists of two cases, it seeks closed form solutions for the non-linear feedback controls (aerodynami c and thrust), which are necessary to transfer the (TAV) from one spec ified state to another specified state, while satisfying pairs of equa lity constraints (that is, Case I: constant acceleration with constant dynamic pressure and Case II: constant rate of climb with constant dy namic pressure). This leads to closed form solutions for the controls in feedback form and also for the heat rate and load. The analytical a pproach gives a reasonable approximation of the general ascent traject ory to orbit, where the two cases can be used in combination with diff erent constant values of the constraints in different levels of the hy personic trajectory. The analytical results were a useful guide in the numerical studies. The second part describes numerical simulation and optimization. The control laws, which minimize the heat load, are fou nd in feedback form. A numerical example is worked out for illustratio n. The trajectory corridor and, in general, all the constraints are sa tisfied for heat load less than or equal to 350 kJ/cm(2) using feasibl e controls.