The propulsion system of a projectile is very important for the aerospace industry. To perform space exploration mission, controlling position and posture of the projectile in the terminal stage is very important. In this study, a new lateral thrust system is proposed to control the position and posture of the projectile at the terminal stage. Based on nozzles in a lateral thruster, a high-speed projectile can instantly change its position and posture. After changing its position and posture, reverse thrust is generated to control unnecessary movements for stabilizing. Based on various tests, the operation and performance of the nozzle opening device (NOD) of the separation mechanism were validated. As a result, excellent reproducibility was confirmed with standard deviation of 0.057 ms for the time from the end of igniter operation to the start of NOD separation. The internal pressure of the chamber and NOD separation time were inversely proportional to each other with a linear relation. The internal pressure of the chamber and flight speed of NOD were also proportional to each other. The flight speed of NOD was 37.53 m/s at the maximum expected operation pressure (β), 30.26 m/s at 0.5 β, and 17.05 m/s at 0 psi.

Intersecting holes deep inside a workpiece, are difficult to deburr because of poor accessibility. When holes are small and the intersecting angle (acute angle between hole axes) is less than 45°, difficulty is at its extreme. In this study, abrasive flow machining is used for a hole diameter of 3mm and intersecting angles of 30° and 45°. Tests were performed for AL6061 specimens, with process parameters allocated to L8(2⁷) orthogonal array. Degree of deburring is strongly dependent on intersecting angle, abrasive grit size, and total volume of flow. Successful deburring was achieved for 30° intersecting angle.

The mechanical drilling of micro holes is considered a difficult endeavor, due to the high hardness and brittleness of alumina plates found during the drilling process. In this work, an alumina plate with a 4mm thickness is drilled with the use of a continuous-wave Nd:YAG fiber laser. As can be seen, there is minimum required power density to ablate the alumina plate. As shown in this study, the hole diameter and straightness are not constant with the hole depth recorded, which is presumably due to the recondensation of vaporized alumina, and the characteristics of irregular laser radiation. The oxygen pressure, power density, focal position, and laser on time (duration) are chosen as the control parameters. To understand the influence of control parameters, the orthogonal arrays table in Taguchi method is applied, and the micro holes are evaluated based on the use of geometrical factors. Through the review of a sensitivity and interaction analysis, the appropriate duration and oxygen pressure are identified as the major parameters governing the geometrical quality of drilled holes in this study.