The Korean Institute of Technology Satellite (KITSAT-1) is the first satellite developed by the Satellite Technology Research Center and the University of Surrey. KITSAT-1 is orbiting the Earth’s orbit as space debris with a 1,320 km altitude after the planned mission. Due to its relatively small size and altitude, tracking the KITSAT-1 was a difficult task. In this research, we analyzed the tracking results of KITSAT-1 for one year using the Midland Space Radar (MSR) in Texas and the Poker Flat Incoherent Scatter Radar (PFISR) in Alaska operated by LeoLabs, Inc. The tracking results were analyzed on a weekly basis for MSR and PFISR. The observation was conducted by using both stations at an average frequency of 10 times per week. The overall corrected range measurements for MSR and PFISR by LeoLabs were under 50 m and 25 m, respectively. The ionospheric delay, the dominant error source, was confirmed with the International Reference of Ionosphere-16 model and Global Navigation Satellite System data. The weekly basis orbit determination results were compared with two-line element data. The comparison results were used to confirm the orbital consistency of the estimated orbits.

The Optical Wide-field patroL-Network (OWL-Net) is a global optical network for Space Situational Awareness in Korea. The primary operational goal of the OWL-Net is to track Low Earth Orbit (LEO) satellites operated by Korea and to monitor the Geostationary Earth Orbit (GEO) region near the Korean peninsula. To obtain dense measurements on LEO tracking, the chopper system was adopted in the OWL-Net’s back-end system. Dozens of angle-only measurements can be obtained for a single shot with the observation mode for LEO tracking. In previous work, the reduction process of the LEO tracking data was presented, along with the mechanical specification of the back-end system of the OWL-Net. In this research, we describe an integrity assessment method of time-position matching and verification of results from real observations of LEO satellites. The change rate of the angle of each streak in the shot was checked to assess the results of the matching process. The time error due to the chopper rotation motion was corrected after re-matching of time and position. The corrected measurements were compared with the simulated observation data, which were taken from the Consolidated Prediction File from the International Laser Ranging Service. The comparison results are presented in the In-track and Cross-track frame.

A strategy is needed for a regional survey of geosynchronous orbits (GSOs) to monitor known space objects and detect uncataloged space objects. On the basis of the Inter-Agency Debris Committee’s recommendation regarding the protected region of geosynchronous Earth orbit (GEO), target satellites with perigee and apogee of GEO ± 200 km and various inclinations are selected for analysis. The status of the GSO region was analyzed using the satellite distribution based on the orbital characteristics in publicly available two-line element data. Natural perturbation effects cause inactive satellites to drift to two stable longitudinal points. Active satellites usually maintain the designed positions as a result of regular or irregular maneuver operations against their natural drift. To analyze the detection rate of a single optical telescope, 152 out of 412 active satellites and 135 out of 288 inactive satellites in the GSO region were selected on the basis of their visibility at the observation site in Daejeon, Korea. By using various vertical view ranges and various numbers of observations of the GSO region, the detection efficiencies were analyzed for a single night, and the numbers of follow-up observations were determined. The orbital estimation accuracies were also checked using the arc length and number of observed data points to maintain the GSO satellite catalog.

This study was conducted to clarify the relation of the species of genus Sorbus in Korea based on multivariate analysis for the morphological characteristics and DNA polymorphism. Twenty-eight quantitative characters were assessed and analyzed by the principal component analysis and UPGMA cluster analysis. From the principal component analysis of 28 quantitative characters, three principal components (PC’s) explained the variation of inter-specific relations among the genus Sorbus. The first PC’s explained 58.95% of the variation with the Eigenvalue of 16.5, and the second and third PC’s showed the Eigenvalue of 8.3 and 3.1 and explained 88.74% and 100.0% of the variation, respectively. Especially, the first PC’s was related in order of the fruit width (FW) and length of terminal leaflet (LTL), petal length (PL), width of terminal leaflet (WTL), and diameter of winter bud (DWB). The second and third PC’s were involved in order of the No. of leaflet (NL), No. of fruit per fruiting lateral (NFL), length of upper rachis (LUR), and diameter of rachis (DR), No. of pistil (NP), respectively. Cluster analysis using them UPGMA method based on the principal components of four species of the genus Sorbus divided into two groups. Group Ⅰ comprises Sorbus commixta and S. sambucifolia var. pseudogracilis, and Group Ⅱ consists of S. amurensis and S. aucuparia. The pattern of DNA polymorphism of the 56 inter-simple sequence repeat (ISSR) markers revealed that different taxa shared different sets of bands, and DNA analysis is useful for taxonomic study on the genus Sorbus.