Crew Exploration Vehicle Skip Entry Trajectory

This research effort develops a program using MATLAB to solve the equations of motion for the atmospheric reentry of the Crew Exploration Vehicle (CEV) which is assumed to be in the phase of a lunar return trajectory that could be initiated any time during the mission. The essential reason for this research is to find a solution for the problem of an unplanned lunar return in addition to the normal procedures. Unlike Apollo type missions, the CEV would still be able to land on any preplanned available landing sites without any additional delay. In Apollo type missions, the return phase had to be initiated in a restricted time window so that the crew module could enter the atmosphere at the preplanned time and be able to land at the planned landing site. Using skip entry procedures, landing location and time will be more accurate in addition to having the time flexibility for reentry. This MATLAB program is designed to find the reentry parameters for given landing location according to the current alignment of the moon using a lunar return speed including the atmospheric trajectory of the CEV.