• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.1
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• pp.68-76
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• 2022

Upper stage of the Korea Space Launch Vehicle-II(KSLV-II) uses a 7-tons class liquid rocket engine and is an open gas generator cycle with a turbopump supply method that uses kerosene/liquid oxygen as the propellant combination. This study first provided a brief overview of the design and development process of the upper stage engine. In addition, it introduced the solutions and results applied to some of the problems that occurred during the development process of the upper stage engine.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.109-115
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• 2011

Development cases of space launch vehicle upper stage engine were studied. HM-7, Vinci, LE-5, RL10 engines are representative upper stage engines of Europe, Japan, and United States. It was realized that upper stage engines were developed with more than two engine test facilities and the development period was 5 to 8 years accompanied with 10~11 engines.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.2
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• pp.125-130
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• 2018

The technology development of a high performance upper stage engine for a GEO(GEostationary Orbit) KSLV(Korea Space Launch Vehicle) is undergoing in Korea Aerospace Research Institute. KSLV is composed of an open cycle engine with gas generator, which is for a low orbit launch vehicle. However the future GEO launch vehicle requires a high performance upper stage engine with a high specific impulse. The staged combustion cycle engine is necessary for this mission. In this paper, current progress and future plan for staged combustion cycle engine development is described.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.108-111
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• 2017

High performance upper stage engine is necessary for space launch vehicles of geostationary orbit, and staged combustion cycle engine is suitable due to high specific impulse. Technology demonstration model for 9 tonf class staged combustion cycle engine, which is consisted of turbopump, preburner, combustion chamber and supply system, was assembled, and hot-firing test was conducted for three seconds in Upper-stage Engine Test Facility of Naro Space Center. Ignition, combustion and shut down of engine system was performed normally, and its performance parameters were evaluated.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.807-808
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• 2010

To insert payload to the orbit over the 200km-altitude using launch vehicle which has 300sec the Isp, multi staging technique for launch is necessary. The range between the sea-level to the transfer orbit about 200~250km is for operation of 1st and 2nd rocket engines and the higher altitude is for propulsion system of the acceleration block and satellite. The upper stage rocket engine should have the high technology for entering the payload into the orbit precisely more than the performance for high thrust level. With this investigation of the upper stage rocket engines which have been used, we want to understand their development trend and prospect which is going to be references for the development of ours.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.2
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• pp.79-95
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• 2022

Since space exploration began in the 1950s, numerous upper stage engines have been developed and used based on various design concepts. In this paper, information of upper stage engines which developed or developing is analysed and their characteristics and performance are summarized. These days, there are many cases of commercial heavy launch vehicles applying upper stage engines using liquid hydrogen with expander cycle which launched recently. Engines operating by Kerosene seem to be close to its theoretical maximum performance based on past experiences. Meanwhile, engines using methane propellant, which has recently become an issue, are also undergoing many developments because of various advantages. Recently, private companies are actively participating in launch vehicle market, and there are many cases in which the government and companies jointly research of next-generation engine.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.4
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• pp.54-63
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• 2022

A 3-tonf class liquid rocket engine that powers the upper stage of a small launcher and lifts 500 kg payload to 500 km SSO is designed. The small launcher is to utilize the flight-proven technology of the 75-tonf class engine for the first stage. A combination of liquid oxygen and liquid methane has been selected as their cryogenic states can provide an extra boost in specific impulse as well as enable a weight saving via the common dome arrangement. An expander cycle is chosen among others as the low-pressure operation makes it robust and reliable while a specific impulse of over 360 seconds is achievable with the nozzle extension ratio of 120. Key components such as combustion chamber and turbopump are designed for additive manufacturing to a target cost. The engine system provides an evaporated methane for the autogenous pressurization system and the reaction control of the stage. This upper stage propulsion system can be extended to various missions including deep space exploration.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.159-162
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• 2008

In this study, various cycles of liquid rocket engines were surveyed and specifically gas generator after burning cycle was investigated for upper stage motors. The engines for the upper stage can be categorized into three group based on the cycles and propellants at the diagram. Kerosene engines which adapt the gas generator after burning cycle and are located in the region II, are characterized for high combustion pressure and complexity. This cycle usually needs more than two pumps to use the turbine power efficiently. The fuel line can be divided into the gas generator line and the combustor line, and only the gas generator line is need to be pressured more because the combustion pressure in the gas generator is much higher than that of the combustor. Basically, all the oxidizer goes into the gas generator and than to the combustor, thus the auxiliary LOx pump is not critically necessary. However, for the various reasons, the LOx line requires a booster pump. A gas generator after burning cycle engines produces relatively high specific impuls than that of the open cycle engines. Thus it is suitable for upper stages of launch vehicles.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.3
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• pp.119-126
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• 2019

For rockets using cryogenic liquid hydrogen or liquid oxygen, chilling is required to avoid cavitation and surge problems. Chilling is categorized by the initial chilling/filling stage and the low-temperature maintenance stage. In addition, to improve satellite insertion capability, a multi-ignition capability is required and accordingly chilling to prepare for the next ignition during low-gravity coasting is also required. This paper describes the overall aspects of filling and low temperature maintain marinating for the booster and the upper stage engine including chilling for multi-ignition.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.4
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• pp.64-71
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• 2022

For the development of an improved upper-stage engine, research on a staged combustion cycle liquid rocket engine is in progress. A cold flow test, ignition test, and combustion test plans were established and performed to develop reignition combustion technology. In order to solve the problem of purge gas flowing into the fuel line, which may cause cavitation in the turbo pump during reignition, the test results of each stage were analyzed. Based on the analysis results, the purge gas inflow problem was solved by reducing the overlapping time between the operation of the bubble removal valve and the opening of the purge valve and the engine fuel valve. Based on this, the reignition combustion test was successfully performed.