Reverse Engineering of Athena II Launcher

Abstract

This report gives details about the model of the Athena II launch vehicle that was created with the goal to use it in the frame of the AtILa study. The small and medium payload launch vehicle Athena II is analyzed with respect to its performance, mass, launch trajectory and orbit characteristics. The motor efficiencies of the first and second stage Castor 120 motor are calculated and compared to available public data. In addition, the third stage thrust and chamber pressure histories are also reverse engineered. A simplified mass estimation is then performed for each stage. Lastly, utilizing the calculated mass breakdown and performance characteristics, a trajectory and orbit analysis is conducted assuming a circular sun-synchronous orbit at 687 km (corresponding to the particular mission studied in the frame of the AtILa study). The results show that the vehicle is capable of launching 1198 kg of payload to this orbit, a difference of 4 % compared to value from available literature and where part of the discrepancy can be attributed to some inaccuracy and discrepancies in the published data. The analysis conclusively proves that the available data for the Athena II launch vehicle are indeed accurate and the reverse engineering process is successful. The calculated trajectory is also considered as representative of the real flight and is aimed to be used for the AtILa project.