| Skip entry for a crewed lunar return mission is analyzed, asserting that precision landing is not feasible when the vehicle lift-to-drag ratio drops below 0.3. The use of a flap to modify the trim angle-of-attack is examined using incidence angle and computational fluid dynamics methods. For a preliminary design, a flap of 1.0 m2 in surface area can increase the trim lift-to-drag ratio from 0.26 to 0.305 and increase cross-range by 200 km. A revised capsule design which more closely reflects Orion shows some deviation between CFD and incidence angle methods. The same flap increases the L/D from 0.325 to 0.350 and provides 100 km of additional cross-range. Heating analysis indicates the flap would require some ablative. Including the center of gravity offset effect of the flap, ballast is found to be more effective than a flap weighing more than 20 kg/m2. |
