Rancang Bangun Motor Roket Padat Kalium Nitrat-Sorbitol (KNSB) untuk Peluncur Roket Sonda dengan Ketinggian 2 km

YONATHAN DESTIANTO, Prof. Dr. Ir. Gesang Nugroho, S. T., M. T., IPM.

2026 | Skripsi | TEKNIK MESIN

Penelitian atmosfer pada ketinggian Planetary Boundary Layer (2 km) memerlukan wahana roket sonda yang andal, tetapi pengembangan roket sonda di Indonesia terkendala oleh keterbatasan teknologi propelan yang ekonomis serta minimnya validasi performa motor roket secara empiris melalui pengujian statis di lingkungan riset universitas. Propelan padat berbasis gula Kalium Nitrat-Sorbitol (KNSB) berpotensi menjadi solusi propelan alternatif yang ekonomis, tetapi pemanfaatannya dalam pengembangan motor roket riset di Indonesia masih sangat terbatas. Oleh karena itu, penelitian ini bertujuan untuk merancang, memanufaktur, serta menguji dan memvalidasi performa motor roket padat KNSB sebagai komponen peluncur roket sonda untuk mencapai ketinggian 2 km.

Penelitian dilakukan melalui tahapan perancangan motor roket meliputi design requirements objectives (DRO), conceptual design, preliminary design, dan detailed design, dengan perhitungan performa motor menggunakan metode Excel SRM Nakka yang divalidasi melalui simulasi OpenMotor serta simulasi penerbangan menggunakan OpenRocket. Selanjutnya dilakukan proses manufaktur komponen casing, top cap, nozzle, dan grain propelan KNSB, dilanjutkan dengan pengujian kualitas propelan, assembly motor roket, serta pengujian statis sebanyak dua kali untuk memperoleh data gaya dorong aktual. Data hasil pengujian statis selanjutnya diolah dan dibandingkan dengan hasil perhitungan teoritis dan simulasi, serta digunakan sebagai input simulasi penerbangan guna memvalidasi capaian ketinggian.

Hasil penelitian menunjukkan bahwa motor roket padat KNSB berhasil dirancang dengan dimensi diameter luar 76,2 mm dan panjang 440,4 mm, menghasilkan performa simulasi OpenMotor berupa total impuls 2078,66 Ns, impuls spesifik 113,49 s, dan klasifikasi motor kelas K, dengan prediksi apogee 2190 m. Hasil pengujian statis menunjukkan performa yang konsisten dengan total impuls 1920,39 dan 1986,99 Ns serta apogee 1919 dan 2026 m, meskipun ditemukan gaya dorong puncak aktual yang lebih tinggi 26–40% dibandingkan hasil teoritis akibat variasi densitas dan laju pembakaran propelan. Secara keseluruhan, motor roket padat KNSB hasil rancang bangun terbukti mampu memenuhi target performa misi roket sonda ketinggian 2 km.

Atmospheric research at the Planetary Boundary Layer altitude (2 km) requires a reliable sounding rocket vehicle; however, sounding rocket development in Indonesia is hindered by the limited availability of economical propellant technology and the lack of empirical rocket motor performance validation through static testing within university research environments. Sugar-based solid propellant, namely Potassium Nitrate-Sorbitol (KNSB), has the potential to serve as an economical alternative propellant solution, yet its application in research rocket motor development in Indonesia remains very limited. Therefore, this research aims to design, manufacture, test, and validate the performance of a KNSB solid rocket motor as the propulsion component of a sounding rocket to reach an altitude of 2 km.

The research was conducted through the rocket motor design stages, comprising Design Requirements and Objectives (DRO), conceptual design, preliminary design, and detailed design, with motor performance calculated using the Nakka Excel SRM method and validated through OpenMotor simulation as well as flight simulation using OpenRocket. This was followed by the manufacturing process of the casing, top cap, nozzle, and KNSB propellant grain components, continued with propellant quality testing, rocket motor assembly, and static testing conducted twice to obtain actual thrust data. The static test data were then processed and compared with the theoretical calculation and simulation results, and subsequently used as input for flight simulation to validate the altitude achievement.

The results show that the KNSB solid rocket motor was successfully designed with an outer diameter of 76.2 mm and a length of 440.4 mm, yielding OpenMotor simulation performance of 2078.66 Ns total impulse, 113.49 s specific impulse, and a class K motor classification, with a predicted apogee of 2190 m. The static test results demonstrated consistent performance with total impulses of 1920.39 and 1986.99 Ns and apogees of 1919 and 2026 m, although the actual peak thrust was found to be 26–40% higher than the theoretical and simulation results due to variations in propellant density and burn rate. Overall, the developed KNSB solid rocket motor was proven capable of meeting the performance target of a 2 km sounding rocket mission.

Kata Kunci : motor roket padat, propelan KNSB, roket sonda, pengujian statis, OpenMotor