• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.3
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• pp.32-42
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• 2022

The strategy to develop a launch vehicle family by bundling multiple rocket engines of a single type has been proven by SpaceX and their reusable fleet comprised of Falcon 9 and Falcon Heavy. In this study, we revisit a potential launch vehicle family out of a 35 tonf-class methalox staged combustion cycle engine and evaluate their utility and performance in various space missions. For example, a Korean version of Falcon 9 can deliver 4.7 tons of payload into 500 km SSO in an expendable mode while the payload is reduced to 2.16 tons in a sea-landing reusable mode. A Korean version of Falcon Heavy can deliver 4.4 tons into GTO when launched from the Naro Space Center, indicating that this common booster core configuration can handle Cheollian 2 albeit the high inclination. Once developed, the same methaloax engine can power the first-stage of smallsat launch vehicles and air launch vehicles.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.10
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• pp.745-752
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• 2020

A numerical study was carried out to evaluate the aerodynamic characteristics of the supersonic grid fins installed on SpaceX Falcon 9. The unit-grid-fin concept was utilized for more efficient and simpler 3-D steady flow calculations. Pre- and post-correction processes that accounted the interference effects by the angle of attack of the missile, the influences of the outer frame of the grid fin and the connecting rods were improved in the study, and it was demonstrated that the present correction method was more accurate as compared to previous studies. Finally, the present approach was applied to evaluate the aerodynamic characteristics in transonic/supersonic flights of SpaceX Falcon 9 with various angle of attacks.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.6
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• pp.72-86
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• 2019

SpaceX is currently leading the global launch market with the successful launch and recovery of Falcon 9 v1.2 Block 5. SpaceX developed Merlin engine, a kerosene gas generator engine, and continuously upgraded the engine from Falcon 1 to Falcon Heavy to increase payload weight. SpaceX suffered a lot of failures early on, but with the help of NASA, it was possible to overcome many crises and develop vehicles. In addition, it successfully developed reusable vehicles, which drastically reduced operating costs. Subsequent launch vehicles in Korea also need to be developed with reference to SpaceX's development strategy.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.12
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• pp.997-1010
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• 2021

This study collected and analyzed flight data of SpaceX's Falcon 9 launch vehicle. All missions were classified by orbital types, such as Polar, SSO, ISS, LEO and GTO missions. In characteristic maneuvers of main engine cutoff, boostback, reentry and landing burn at each stage of 1st stage launch vehicle, changes of the physical parameters like speed, altitude, dynamic pressure and acceleration were investigated. The guidelines derived from detailed maneuver analysis were suggested, which can be used as design and evaluation references for developing reusable launch vehicle.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.8
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• pp.609-615
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• 2021

Three-dimensional numerical study was carried out to evaluate the aerodynamic characteristics of the supersonic grid fins installed on SpaceX Falcon 9. The present three-dimensional flow results were compared to the results by the concept of the unit grid fin previously introduced for more efficient and simpler flow calculations, and the validity of the approach of the unit grid fin were evaluated. The aerodynamic characteristics in supersonic flights Mach 2.8 of SpaceX Falcon 9 with various angle of attacks were also obtained.

• The KIPS Transactions:PartC
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• v.9C no.4
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• pp.467-472
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• 2002

Recently, Networks are required to adopt the security system and security consulting because of security threats and vulnerabilities of systems. Enterprise Security Management (ESM) is a system which establishes the security zone composed of security systems and Firewalls and applies the security policy to each security system. A relevant ESM is based on the effective policy and the proper security system. Particularly, multiple firewalls in ESM are concerned with the security policy about each traffic. In this paper, we describe the problems that can be occurred when we select the firewalls to apply security policy of access control in ESM composed of multiple firewalls and propose the FALCON algorithm, which is able to select the firewalis to apply the policy. We expect that FALCON algorithm offers stability, scalability and compactness for selecting firewall set.

• The Journal of the Acoustical Society of Korea
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• v.39 no.4
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• pp.322-330
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• 2020

This study investigates the far-field noise from three Falcon 9 vehicle launches from Vandenberg Air Force Base, CA, USA, as measured from the same location within the nearby community of Lompoc. The overall sound pressure levels for the three launches are shown to be similar, but some differences in the early launch period are thought to be weather-related. The peak directivity angle in overall level is approximately 65 deg, which is consistent with horizontally-fired, static rocket data. For the third launch, waveforms and spectra are analyzed for different events during the launch sequence. The measured spectral bandwidth decreases with time, but spectral levels remain above the ambient noise throughout the main-engine firing. Additionally, late-launch phenomena observed in the data appear to be correlated with main-engine cutoff and second-stage engine start.

• Journal of Astronomy and Space Sciences
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• v.40 no.3
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• pp.123-129
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• 2023

This paper presents an analysis of the trans-lunar trajectory insertion performance of the Korea Pathfinder Lunar Orbiter (KPLO), the first lunar exploration spacecraft of the Republic of Korea. The successful launch conducted on August 4, 2022 (UTC), utilized the SpaceX Falcon 9 rocket from Cape Canaveral Space Force Station. The trans-lunar trajectory insertion performance plays a crucial role in ensuring the overall mission success by directly influencing the spacecraft's onboard fuel consumption. Following separation from the launch vehicle (LV), a comprehensive analysis of the trajectory insertion performance was performed by the KPLO flight dynamics (FD) team. Both orbit parameter message (OPM) and orbit determination (OD) solutions were employed using deep space network (DSN) tracking measurements. As a result, the KPLO was accurately inserted into the ballistic lunar transfer (BLT) trajectory, satisfying all separation requirements at the target interface point (TIP), including launch injection energy per unit mass (C3), right ascension of the injection orbit apoapsis vector (RAV), and declination of the injection orbit apoapsis vector (DAV). The precise BLT trajectory insertion facilitated the smoother operation of the KPLO's remainder mission phase and enabled the utilization of reserved fuel, consequently significantly enhancing the possibilities of an extended mission.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.3
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• pp.101-112
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• 2021

SpaceX shows various strategies such as constructing various payload portfolio through the reuse of Falcon 9 and Falcon Heavy, constructing the launch vehicles using one type of engine, the transition from kerosene engine to methane engine, and the use of 3D printing. In this study, launch vehicle proposals that can cover a variety of payloads and trajectories from KOMPSAT to GEO-KOMPSAT were constructed, and ten launch vehicles using kerosene gas generator cycle engine, kerosene staged-combustion cycle engine, and methane staged-combustion cycle engine were reviewed. Of the ten launch vehicles, the reusable launch vehicle using a 35-ton methane engine was rated as the best in terms of development potential.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.5
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• pp.53-64
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• 2021

SpaceX has lowered rocket launch cost innovatively and put first stage reuse to the practical use with Falcon 9. Now the company is developing Starship system that is fully reusable with the heaviest payload in the world. So the system can lower the cost much more and fulfull more diverse mission. For the system the company have developed Raptor engine which is a full-flow staged combustion cycle one with methane fuel. And for the full reusability the company is manufacturing and testing the system prototypes with the barely used technologies such as stainless steel tank, belly flop and retropropulsion during descent. In this study the specification, missions and design features of the system are investigated. Also the development processes of Raptor engine and initial 13 Starship prototypes, which have been manufactured very rapidly, are presented.