Considerations of Applying Continuous Thrust During Synergetic Plane Changing

摘要

An investigation was made of the interactions of thrust and lift on equilibrium reentry trajectories to determine if the use of thrust during a turn will reduce the heat input to a winged spacecraft. In the maneuver considered in the study, propulsion is used shortly after the vehicle enters the atmosphere to cancel drag and provide additional lift, so that much of the heading change will occur during the cruise phase at constant vehicle velocity. Engine thrust is increased at the end of cruise to accelerate the vehicle into a new orbit, thus decreasing heating rates and vehicle temperatures. A variable-thrust engine is assumed. The study shows that by using propulsion during the turning phase of flight, the structural temperatures of lifting vehicles can be lowered by about 500 degrees F, compared with the temperatures encountered when the turn is made during a pure glide phase. If the turn is made at high velocity, fuel loss is minimized by using very large bank angles. No losses in vehicle performance were noted, and normal load factors were decreased. (Author)