Orion是當今最先進的太空船之一，其將會在近期執行深度太空任務，例如火星任務及小行星登陸。此外，Orion太空船是鈍體的一種，因此，高度的壓力阻力及空氣動力加溫現象會在重返大氣層時體驗到。 被震波所激起的壓力阻力及氣動力加熱是極音速飛行的主要挑戰，並且為了更好的熱分佈，鈍體乃是在極音速流域中的主要構型，但其會在物體表面上引致大量的阻力。因此，氣尖與氣盤均可被有效地運用來當作減阻之方法。此外，極音速物體的減阻及熱傳之意涵在未來的太空科學與科技發展之中扮演一個很重要的角色。 在此份論文中，我們將研究伴隨不一樣間隙寬度的氣盤之氣尖裝置在減阻上的效應。因此，我們透過ANSYS Fluent來執行一連串的計算流體力學(CFD)數值模擬工作以研究及解釋極音速流體流經鈍體的相關行為現象。此外，氣尖鈍體的阻力係數及其相關減阻效率將可以透過克里金法的最佳化演算法來得到。 對於我們所研究的構型之中，我們可以發現有氣尖裝置的鈍體之阻力遠低於其在無氣尖時。減阻效率將被迴流區域的大小規模所主導，其會隨著氣尖長度及氣盤間隙大小的增加而增加，故減阻性能將相依於物體的設計參數，例如主物體構形、氣尖長度、頂端形狀與減阻方法。本論文之結果可以成為未來極音速鈍體及太空探測載具之設計基石。 Orion MPCV (Multi-Purpose Crew Vehicle) is one of the state-of-the-art manned space vehicles nowadays which will engage in the deep space missions in the near future such as the journey to Mars and the asteroid landing. Besides, Orion spacecraft is a kind of blunt body, thus the phenomena concerning the high levels of pressure drag and aerodynamic heating are experienced during the atmospheric re-entry process. Pressure drag and aeroheating stirred by the shock wave is the main challenge of hypersonic flight, and the blunt body is always the principle configuration at hypersonic flow regime for heat distribution, but it would induce tremendous drag to the body. Therefore, both aerospikes and aerodisks can be efficiently utilised as the approach for drag reduction purpose. Furthermore, the implication of drag and heat transfer reduction for the hypersonic bodies plays a crucial part in the future development of space science and technology. In this thesis, we would research the effect of different geometric shapes of aerospikes with different disk gap widths on drag reduction. Accordingly, we implemented a series of Computational Fluid Dynamics (CFD) numerical simulation work via ANSYS Fluent CFD code to investigate and interpret the behaviour in relation to hypersonic flow over aerospiked blunt bodies. Moreover, the drag coefficient and the drag reduction efficiency of spiked blunt bodies would be worked on and acquired via Kriging-based optimisation method. For the models we studied, we found that the drag on the spiked blunt bodies is much lower than the spike off one. The drag reduction efficiency especially would be predominated by the scale of recirculation zone, which increases as both the spike length and the gap size of aerodisk increase. Hence, the performance of drag diminution will depend on the design parameters of bodies such as main body configurations, aerospike length, tip geometric shapes and drag reduction schemes. The results from this research could be the cornerstone for the design of future hypersonic blunt bodies and space exploration vehicles.