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1984년 ~ 2024년까지 1,246 건의 한국우주과학회지를 계간으로 확인하실 수 있습니다.
- The Korean Space Science Society (The Korean Astronomical Society)
- 계간 (Quarterly)
- ISSN : 1225-052x (ISSN : 1225-052x)
1225-052x
- DB구축현황 : 1,246건 (DB Construction : 1,246 Articles)
총 게시글 1,246건
페이지 1/125
1
- Shinhye Moon
- Journal of astronomy and space sciences
- 41, n.2
- pp.61-78
- 2024
- 원문 바로보기
This study developed a real-time spacecraft pose estimation algorithm that combined a deep learning model and the least-squares method. Pose estimation in space is crucial for automatic rendezvous docking and inter-spacecraft communication. Owing to the difficulty in training deep learning models in space, we showed that actual experimental results could be predicted through software simulations on the ground. We integrated deep learning with nonlinear least squares (NLS) to predict the pose from a single spacecraft image in real time. We constructed a virtual environment capable of mass-producing synthetic images to train a deep learning model. This study proposed a method for training a deep learning model using pure synthetic images. Further, a visual-based real-time estimation system suitable for use in a flight testbed was constructed. Consequently, it was verified that the hardware experimental results could be predicted from software simulations with the same environment and relative distance. This study showed that a deep learning model trained using only synthetic images can be sufficiently applied to real images. Thus, this study proposed a real-time pose estimation software for automatic docking and demonstrated that the method constructed with only synthetic data was applicable in space.
2
- Moon-Jin Jeon
- Journal of astronomy and space sciences
- 41, n.1
- pp.43-60
- 2024
- 원문 바로보기
Korea Pathfinder Lunar Orbiter (KPLO) is South Korea's first space exploration mission, developed by the Korea Aerospace Research Institute. It aims to develop technologies for lunar exploration, explore lunar science, and test new technologies. KPLO was launched on August 5, 2022, by a Falcon-9 launch vehicle from cape canaveral space force station (CCSFS) in the United States and placed on a ballistic lunar transfer (BLT) trajectory. A total of four trajectory correction maneuvers were performed during the approximately 4.5-month trans-lunar cruise phase to reach the Moon. Starting with the first lunar orbit insertion (LOI) maneuver on December 16, the spacecraft performed a total of three maneuvers before arriving at the lunar mission orbit, at an altitude of 100 kilometers, on December 27, 2022. After entering lunar orbit, the commissioning phase validated the operation of the mission mode, in which the payload is oriented toward the center of the Moon. After completing about one month of commissioning, normal mission operations began, and each payload successfully performed its planned mission. All of the spacecraft operations that KPLO performs from launch to normal operations were designed through the system operations design process. This includes operations that are automatically initiated post-separation from the launch vehicle, as well as those in lunar transfer orbit and lunar mission orbit. Key operational procedures such as the spacecraft's initial checkout, trajectory correction maneuvers, LOI, and commissioning were developed during the early operation preparation phase. These procedures were executed effectively during both the early and normal operation phases. The successful execution of these operations confirms the robust verification of the system operation.
3
- Dae-Young Lee
- Journal of astronomy and space sciences
- 41, n.1
- pp.1-15
- 2024
- 원문 바로보기
The Korean heliospheric community, led by the Korea Astronomy and Space Science Institute (KASI), is currently assessing the viability of deploying a spacecraft at the Sun-Earth Lagrange Point L4 in collaboration with National Aeronautics and Space Administration (NASA). The aim of this mission is to utilize a combination of remote sensing and in situ instruments for comprehensive observations, complementing the capabilities of the L1 and L5 observatories. The paper outlines longterm scientific objectives, underscoring the significance of multi-point in-situ observations to better understand critical heliospheric phenomena. These include coronal mass ejections, magnetic flux ropes, heliospheric current sheets, kinetic waves and instabilities, suprathermal electrons and solar energetic particle events, as well as remote detection of solar radiation phenomena. Furthermore, the mission's significance in advancing space weather prediction and space radiation exposure assessment models through the integration of L4 observations is discussed. This article is concluded with an emphasis on the potential of L4 observations to propel advancements in heliospheric science.
4
- Ulkar Karimova
- Journal of astronomy and space sciences
- 41, n.1
- pp.35-42
- 2024
- 원문 바로보기
Sungrazing comets, known for their proximity to the Sun, are traditionally classified into broad groups like Kreutz, Marsden, Kracht, Meyer, and non-group comets. While existing methods successfully categorize these groups, finer distinctions within the Kreutz subgroup remain a challenge. In this study, we introduce an automated classification technique using the densitybased spatial clustering of applications with noise (DBSCAN) algorithm to categorize sungrazing comets. Our method extends traditional classifications by finely categorizing the Kreutz subgroup into four distinct subgroups based on a comprehensive range of orbital parameters, providing critical insights into the origins and dynamics of these comets. Corroborative analyses validate the accuracy and effectiveness of our method, offering a more efficient framework for understanding the categorization of sungrazing comets.
5
- Choi, Dooyoung
- Journal of astronomy and space sciences
- 41, n.4
- pp.271-281
- 2024
- 원문 바로보기
<P> This paper presents ground calibration and orthogonality correction methods for the tri-axis fluxgate magnetometer (FGM), named as adaptive in-phase magnetometer (AIMAG), aboard the CAS500-3 satellite. The orthogonality errors of the FGM among the axes can lead to significant inaccuracies in magnetic field measurements. In this study, we employed Helmholtz coils and an autocollimator to apply controlled magnetic fields and adjust the magnetometer’s alignment. By deriving the correction matrix, we could transfer the sensor axes to the ideal orthogonal coordinate system. We validated the correction method by analyzing the sensor’s output under various magnetic field conditions. This correction method is expected to enhance the in-flight magnetic field measurements of the CAS500-3 satellite. </P>
6
- Abbas, Sheer
- Journal of astronomy and space sciences
- 41, n.4
- pp.235-247
- 2024
- 원문 바로보기
<P> The advent of “space tourism” has induced outer space law to respond and adapt to this dramatic growth because of the principled contribution of private entities in these activities. This article discusses the main legal aspects of licensing, supervision, liability, registration, and health side effects, and how these reveal the influence of space tourism. Because of the moral participation of private individuals in these activities, “space tourism” demands that outer space law be modified and adaptable. Although many issues of ship, crew, and passenger certification have not been defined in international law, these would be evaluated to show that domestic legislative interests may drive the law before it reaches international law. Air and adventure tourism laws are also evaluated. Space are not likely to remain limited to professionally trained individuals and wealthy astronauts. The potential for public access to space raises complex legal, health-related, and ethical questions on the inadequacy of the current international legal instruments addressing the utilization and exploration of outer space. Furthermore, this study is designed to evaluate the role of human presence in spaceflights, accidents that occurred to participants of space missions, and other risks spaceflights may induce on humans. In addition, this study focuses on analyzing existing legal regulations related to astronauts’ health and life protection during spaceflight and how states can address emerging challenges to astronauts’ safety. The existing global legal framework regulating aviation and space operations is unsuitable for the widespread commercial entry into space. This is because it was designed when drafters did not envisage such endeavors to this extent. The insufficient legal clarity should be addressed rapidly to set applicable standards to promote such activities. To conclude, this article compares national space regulations and elaborates on the drawbacks of the current international space regulations. </P>
7
- Nurzhan Ussipov
- Journal of astronomy and space sciences
- 41, n.3
- pp.149-158
- 2024
- 원문 바로보기
This study developed a machine learning-based methodology to classify gravitational wave (GW) signals from black hol-eneutron star (BH-NS) mergers by combining convolutional neural network (CNN) with conditional information for feature extraction. The model was trained and validated on a dataset of simulated GW signals injected to Gaussian noise to mimic real world signals. We considered all three types of merger: binary black hole (BBH), binary neutron star (BNS) and neutron starblack hole (NSBH). We achieved up to 96% correct classification of GW signals sources. Incorporating our novel conditional information approach improved classification accuracy by 10% compared to standard time series training. Additionally, to show the effectiveness of our method, we tested the model with real GW data from the Gravitational Wave Transient Catalog (GWTC-3) and successfully classified ~90% of signals. These results are an important step towards low-latency real-time GW detection.
8
- Uk-Won Nam
- Journal of astronomy and space sciences
- 41, n.3
- pp.195-208
- 2024
- 원문 바로보기
As human exploration goals shift from missions in low Earth orbit (LEO) to long-duration interplanetary missions, radiation protection remains one of the key technological issues that must be resolved. The low Earth orbit space radiation dosimeter (LEO-DOS) instrument to measure radiation levels and create a global dose map in the LEO on board the the next generation small satellite-2 (NEXTSat-2) was launched successfully on May 25, 2023 using the Nuri KSLV-III in Korea. The NEXTSat-2 orbits the Earth every 100 minutes, in an orbit with an inclination of 97.8° and an altitude of about 550 km above sea level. The LEO-DOS is equipped with a particle dosimeter (PD) and a neutron spectrometer (NS), which enable the measurement of dosimetric quantities such as absorbed dose (D), dose equivalent (H) for charged particles and neutrons. To verify the observations of LEO-DOS, we conducted a radiation dose estimation study based on the initial results of LEO-DOS, measured from June 2023 to September 2023. The study considered four source categories: (i) galactic cosmic ray particles; (ii) the South Atlantic Anomaly region of the inner radiation belt (IRB); (iii) relativistic electrons and/or bremsstrahlung in the outer radiation belt (ORB); and (iv) solar energetic particle (SEP) events.
9
- Speyerer, Emerson Jacob
- Journal of astronomy and space sciences
- 41, n.4
- pp.249-270
- 2024
- 원문 바로보기
<P> The ShadowCam instrument on the Danuri spacecraft provides high-resolution views of shadowed portions of the Moon, which are illuminated by naturally scattered light from nearby sunlit terrain. The sensitive time-delay integration detector captures high signal-to-noise observations within the permanently shadowed regions and areas in shadow for part of the year. We characterized the geometric properties of the images, enabling accurate placement of observations within the lunar cartographic framework. This work describes the internal and external orientation parameters using laboratory observations and images collected during the cruise and commissioning phase of the mission. We identified a radial distortion in the cross-track direction from these observations, which is correctable during our standard calibration pipeline procedures. We also calculated the pointing of the camera relative to the spacecraft bus within ~0.001°. Using these models, corrections, and the initial ephemeris provided by the Korea Aerospace Research Institute, images can be aligned within 60 m on the surface (95% confidence interval). This calibration and a precise radiometric model will enable reliable interpretation of ShadowCam images and the development of future derived products, including precisely mapped mosaics and meter-scale digital elevation models. </P>
10
- Hyeonji Kang
- Journal of astronomy and space sciences
- 41, n.3
- pp.139-148
- 2024
- 원문 바로보기
A search coil magnetometer (SCM) is a common equipment to observe energy transmission and vibrations in space physics, enabling measurements across a wide frequency range of up to tens of kilohertz. This study proposes the designs of a magnetic core that allows a low-mass sensor and improves its performance: a rod core, sheet-stacked core, and rolling-sheet core. Subsequently, the performance of each sensor was investigated. The sheet-stacked core using the cobalt-based alloy exhibited the highest sensitivity, although it exhibited instability beyond 20 kHz. In contrast, the rod and rolling-sheet core sensors demonstrated stability in the magnetic field measurements (10 Hz-40 kHz). Moreover, the noise equivalent magnetic induction (NEMI) of the rod- and rolling-sheet core sensors were 0.014 pT Hz<sup>-1/2</sup> and 0.012 pT Hz<sup>-1/2</sup> at 1 kHz, respectively. The rolling-sheet core with high relative permeability achieved a mass reduction of over three times that of the rod core while exhibiting sufficient sensitivity.