Trajectory Optimization and Performances of RBCC for Long-Range Return Missions of Reusable Vehicle

Dong Uk Kim; Sang Hun Kang

doi:10.6108/KSPE.2026.30.1.028

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2026 Vol.30, Issue 1 Preview Page Next Page

RESEARCH PAPERS

Trajectory Optimization and Performances of RBCC for Long-Range Return Missions of Reusable Vehicle 재사용 비행체의 장거리 귀환 임무를 위한 궤적 최적화 및 RBCC의 성능 연구

28 February 2026. pp. 28-42

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Abstract

This study analyzes the performance of a Rocket-Based Combined Cycle (RBCC) engine for a reentry vehicle’s long-range return mission using trajectory optimization. Using OpenGoddard, maximum-range trajectories were derived and compared for an X-37B based vehicle equipped with either an RBCC engine or a conventional liquid rocket engine. The analysis revealed that the RBCC engine's performance varied significantly with maximum thrust. Under a low-thrust condition (1 kN), the flight range increased by only 1.13% compared to the rocket, whereas a high-thrust condition (29.4 kN) resulted in a significant 42.91% increase. This is because sufficient thrust enabled an optimal maneuver that first utilized the high-efficiency ramjet mode and subsequently climbed to a high-altitude, low-drag regime. Therefore, securing sufficient thrust is a key design condition for the effective application of an RBCC engine to the long-range missions of reentry vehicles.

Keywords

Rocket Based Combined Cycle

OpenGoddard

Reentry

Trajectory Optimization

X-37B

본 연구에서는 로켓기반 복합사이클(RBCC) 엔진을 재진입 비행체에 적용하여 장거리 귀환 임무를 수행할 때의 성능을 궤적 최적화 기법을 통해 분석하였다. OpenGoddard를 이용하여 X-37B 형상을 참조한 비행체에 RBCC 엔진과 일반 액체로켓 엔진을 장착했을 때의 최대 비행 거리 궤적을 도출하고 비교했다. 해석 결과, RBCC 엔진의 성능은 최대 추력 조건에 따라 큰 차이를 보였다. 저추력(1 kN) 조건에서는 로켓 대비 비행 거리가 1.13% 증가했으나, 고추력(29.4 kN) 조건에서는 42.91% 비행 거리 증대 효과를 확인했다. 이는 충분한 추력이 뒷받침될 때 비행체가 고효율 램제트 모드를 활용한 후 다시 저항이 적은 고고도로 상승하는 최적 기동이 가능했기 때문이다. 따라서 재진입 비행체의 장거리 임무에 RBCC 엔진을 효과적으로 적용하기 위해서는 충분한 추력 확보가 핵심적인 설계 조건임을 알 수 있다.

키워드

로켓기반 복합사이클

오픈고다드

재진입

궤적최적화

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Information

Publisher :The Korean Society of Propulsion Engineers
Publisher(Ko) :한국추진공학회
Journal Title :Journal of the Korean Society of Propulsion Engineers
Journal Title(Ko) :한국추진공학회지
Volume : 30
No :1
Pages :28-42
Received Date : 2025-08-27
Revised Date : 2025-11-18
Accepted Date : 2025-11-27
DOI :https://doi.org/10.6108/KSPE.2026.30.1.028

Journal of the Korean Society of Propulsion Engineers ISSN:1226-6027(Print) 2288-4548(Online) 한국추진공학회지

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