Trajectory Analysis for Vertical Takeoff and Vertical Landing Reusable Launch Vehicle’s Upper Stage

Abstract

Reusable launch vehicles are a promising business for the future because of their flexibility, reliability, low cost, and good operability. There are two takeoff styles: the vertical takeoff and the horizontal takeoff. Compared to the horizontal takeoff vehicle, the vertical takeoff reusable launch vehicle has advantages, such as a shorter down-range landing, a quicker recovery system (wherein takeoff and landing happen in approximately the same location), and a lighter weight. A vertical profile is used for vertical takeoff and vertical landing (VTVL) vehicles to achieve a recovery at the launch site. However, the first stage of the vertical takeoff reusable launch vehicle (RLV) typically can provide a very small or even zero velocity to its second or upper stage, if the upper stage is released at the peak altitude. Therefore, primarily, this type of launch vehicle is used to achieve hundreds of seconds in a microgravity environment. The upper stage payload delivery capabilities of a vertical takeoff RLV and its potential applications are described from a trajectory point of view. A modified optimal control methodology and an intuitive method of the trajectory control, called energy for altitude and time, are used to determine the maximum throw distance, maximum flight time, and orbital insertion capabilities for certain payloads, separately. The results from this investigation show the possibilities of expanding the applications for the VTVL suborbital RLV.