Korea Pathfinder Lunar Orbiter (KPLO) Operation: From Design to Initial Results

Moon-Jin Jeon,Young-Ho Cho,김은혁,Dong-Gyu Kim,Young-Joo Song,홍승범,Jonghee Bae,Jun Bang,Jo Ryeong Yim,Dae-Kwan Kim 한국우주과학회 2024 Journal of Astronomy and Space Sciences Vol.41 No.1

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.

THERRESTRIAL IMPACT CRATERING CHRONOLOGY: A PRELIMINARY ANALYSIS

Moon, Hong-Kyu,Mi, Byung-Hee,Fletcher, Andre-B.,Kim, Bong-Gyu The Korean Space Science Society 2001 Journal of Astronomy and Space Sciences Vol.18 No.3

We have recently compiled a database of the properties of 192 impact craters, which supercedes previous compilations. Using our database, the impact structures found in North America, Europe and Australia have been examined; these cratonic areas have been relatively stable for considerably long geological periods, and thus have been best preserved. It is confirmed that there is a close correlation between the geological epoch boundaries, the epochs of mass extinctions, antral the "timing" of impacts. In addition, the terrestrial cumulative flux of objects >20km is found to be $1.77{\times}10^{-15}km^{-2}yr^{-1}$, over the last 120 Myr, which is much smaller than the published values in McEwen et al. (1997) and Shoemaker (1998) ($5.6{\pm}2.8{\times}10^{-15}km^{-2}yr^{-1}$. For terrestrial impact structures with D> 50 km, the apparent cumulative flux over the last 2450 Myr is ~50 times smaller than the corresponding value for the Moon. If we assume that the Earth and the Moon suffered the same level of bombardment over this time, this would mean that the actual flux of impacting bodies, capable of making craters with D)50 km, was ~ 50 times larger than the apparent flux estimated from the currently known terrestrial records.

척수 경막외 혈관 기형에 의한 재발성 척수병증

오동호,김희태,박운규,이영주,김승현,김주한,김명호,박문향 대한신경과학회 1998 대한신경과학회지 Vol.16 No.5

염분이 함유된 폐수의 생물학적 처리시 염분농도가 오염물질의 제거에 미치는 영향

김상수,문병현,이택순,서규태,공남식 7개 국립대학교 환경연구논문집 공동발행 위원회 2005 공업기술연구 Vol.5 No.-

Effects of salt concentration and C/N ratio on pollutants removal efficiencies were investigated in treatment of seafood wastewater by sequence batch reactor(SBR). The synthetic seafood wastewater containing salinity from 3,000 to 10,000 mg/L NaCI and C/N ratio of 2 and 4 was treated by SBR. Removal efficiencies of COD_(Mn), T-N, and T-P decreased with increasing salt concentration, but eventually reached a pollutants removal a platrau. As systems adapted in salts until salts concentration of 8,000mg/L, the time required to reach the pollutants removal efficiencies at steady state was reduced. However, the removal efficiencies of pollutants sharply decreased and the time require to reach steady state was increased as salt concentration rose to 10,000mg/L, Removal efficiencies of COD_(Mn) were higher for C/N ratio of 4 than for 2. Effects of salt on the nitrogen removal were not faster than the organic removal but the time required to the nitrogen removal at steady state was ncreased. The removal efficiencies of phosphorus also were redueed as salt concentration increased, which inhibited the release of phosphorus than the uptake.

생물학적 폐수처리시 휴지기간이 처리특성에 미치는 영향에 관한 연구

김상수,문병현,서규태,이택수 7개 국립대학교 환경연구 논문집 공동발행 위원회 2004 공업기술연구 Vol.4 No.-

Under recent situation of more stringent effluent regulations, small scale biological process for industrial wastewater treatment has on operational problems, such as highly variable loadings into the system. Especially, the seafood processing industry has difficulties to treat is because of its highly variable organic loading and high saline concentration (>30g/d㎥). High salt concentrations disrupt metabolic functions and cause plasmolysis and/or loss of activity of microbial flora, hence the biological treatment of the saline wastewaters could produce low COD removal efficiency. On the basis of background mentioned above, an appropriate operation of the existing treatment plant is required for stable effluent discharge at even highly influent loading. In this study, effects of long term ( days) idle periods on floc characteristics were investigated in treatment of saline wastewater by SBR. Temporal stop of feeding affects biological activity in the reactors and then floc structures such as size and fractal dimension. After a certain period of reoperation for orgnic activity, the size and fractal dimension of floc start to increase.

병재배 폐톱밥을 이용한 양송이 복토재료 개발에 관한 연구

김홍규,이희덕,김용균,한규홍,문창식,김홍기 충남대학교 생물공학연구소 1999 생물공학연구지 Vol.7 No.-

애느타리 병재배후 탈병한 톱밥을 3월 중순 퇴적하여 부숙시킨 결과 퇴적기간에 따른 폐톱밥의 부숙정도는 퇴적 30일이후에 가장 컸으며 부숙 소요일수는 최소 48일이었다. 퇴적 기간에 따른 폐톱밥의 pH 및 총 질소 함량은 부숙이 진전됨에 따라 증가하는 경향이었고 총 탄소 및 C/N율은 시간이 경과함에 따라 감소하는 경향이었다. 식양토에 부숙이 완료된 톱밥을 부피 비율로 10, 30, 50%씩 첨가하여 복토 재료로 사용한 결과 30% 첨가시 식양토 단용 처리보다 A. bisporus 균사 생장이 촉진되고 초발이 소요일수가 5일 빠르며, 수량에 있어서도 28% 증수되었다. After bottle culture of Pleurotus ostreatus, sawdust was taken out from the bottle and accumulated in the middle of March, and then composted. As the result, Y value was decreased rapidly 30 days after composting, and it was decreased slowly after 30 days. It is considered that 118 days is required for composting, however, it is possible to use for casing material after at least 48 days composting. The pH and total nitrogen content of sawdust based on composting period had tendency to increase as composting was processed. Total carbon and C/N rate had tendency to decrease as time went on. Based on the rate of 10, 30 and 50%, each sawdust was added to clay loam used as casing material for culturing A. bisporrus. Among various treatments, the mycelial growth of A. bisporus was more favorable in the treatment of 30% sawdust than in the single treatment of clay loam. Based on the date necessary for primodium formation of A. bisporus, the primodium formation in the treatment of 30% sawdust was reduced to about 5 days as compared with that of any other treatments When 30% sawdust was added to clay loam used as casing material for culturing A. bisporus, the yield of its fruiting body was increased to 28%.

벽체에 작용하는 토압에 관한 모형실험

김문규,김대현 동의공업대학 2000 論文集 Vol.26 No.1

The model experiments were carried out to observe the variation of lateral earth pressure acting on the wall as vary the constraint of retaining wall, geometry of wall, and backfill width. For the experiments, a soil-box, model wall, and a rainer were designed and manufactured. The experiments were carried out with two different types of constraint on wall movement: i.e. first with completely fixed wall and second with movable wall depending on soil pressure. The measured lateral earth pressure was compared with that by an extended silo and wedge theories. The test results are summarized as follows: The measured lateral earth pressure approached to that from the extended silo theory as a narrower backfill width was used. Both experimental and theoretical results showed a good coincidence when the backfill width is Bc tan(45 -?? DS/2)H. But much deviated from that by an extended wedge theory. (원문을 참조하세요)

진양호 유입수의 홍수기 오염부하 및 수질특성

김영충,서규태,문병현,이택순 7개 국립대학교 환경연구 논문집 공동발행 위원회 2001 환경연구논문집 Vol.1 No.1

This study is to evaluate the characteristics of pollution load into lake Jinyang by flooding. Water quality of Kyongho and Duckcheon river, which are major tributary of lake Jinyang, was analyzed during rainy season. Increased pollution load was observed at initial stage of rainfall. This was caused by pollutants washed out of non-point sources at initial run off. It was considerable that much higher pollution load was measured during the flood than the value calculated using loading rate.

Structure Factor와 Electron Density

金文執,秋錦洪,李珍昊,金珍圭,朴泳秀,徐日煥 충남대학교 기초과학연구소 2000 忠南科學硏究誌 Vol.27 No.2

If electron density ρ(xyz) in a single crystal is known, structure factor F(hkl) can be calculated and, on the contrary, electron density map can be drawn if the structure factor including its phase is known. Therefore the functions ρ(xyz) and F(hkl) are said to be Fourier transforms of each other.

중·고등학생들의 보건교육 요구도 조사연구

문기내,남철현,김귀희,위광복,박경옥,이미경,심규범,장영진 慶山大學校 保健福祉硏究所 2003 保健福祉硏究 Vol.8 No.-

This study was conducted to examine middleㆍhigh school 720 students in seven regions of middleㆍsmall city and town, Myon for 2 months from March 2 through April 30, 2002 in order to realize a side of school health education in middleㆍhigh school and health education need as well as health education specialist in school in the future. The results of this study can be summarized as follows. 1. Health condition is now 'normal' is 51.0%, 'good' is 45.0%, 'not good' is 4.1% and health condition of children is good as much as education level of mother is higher. 2. Experience to learn health education in school for one year recently is 'no' is 39.6%, 'don't know' is 32.6%, 'yes' is 27.8% and it represents health education in school doesn't work well and experience to learn health education is lower and lower in town and Myon. 3. Health education ways to work in school now are 'Movie, Video, Slide' is 40.7%, 'education as groups of nurse-teacher' is 38.6%, 'to distribute health education material and book' is 7.7%, 'education by setting an example' is 3.4%, 'the others' is 9.7%. 4. Time of appropriate health education for one time is 'about a hour' is 56.7%, 'about 30 minute' is 33.8%, 'about two hour' is 7.6%, it represents this situation is because of what students' time is lack and burden about a curriculum in an education administratin and school classed of a focused school score. 5. The average score of satisfaction of health education in school is 16.99±0.58, 'men' is 1.79±0.60, 'women' is 1.61±0.55 as the distinction of sex, satisfaction level of men is higher than women. 6. Learning route about health information is 'through mass media' is 59.9%. 'through family, friend' is 15.0% 'health education lecture' is 7.2%, 'printing media' is 6.1%, 'medical institution' is 5.6%, 'the others' is 5.1%, 'public health center' is 1.0%, 'through mass media' is the highest percent as each 59.1% and 60.6% in all of men and women. 7. The most efficient education way of health education is 'movie, video, slide' is 32.6%, 'health education specialist who works school' is 21.9%, 'school health education by nurse-teacher' is 16.0%, 'way through mass communication' is 11.6%. 8. The appropriate health education specialist in the future is 'health education specialist who has qualifications' is the highest as 64.5%, 'nurse-teacher' is 12.4%, 'medical personnel(doctor, a physician of oriental medicine etc.,)' is 11.0%, 'staff in public health center' is 7.2%, people in other regions(health and medical professor etc.,) is 7.0%, it represents school health education is not actual and is formal now in second hand. 9. The most necessary health education program is 'program of stress solution' is the highest as 24.9%, 'program of no smoking' is 22.7%, 'sexual education program' is 19.8%, 'school violence program' is 8.8%, 'isolate from their friends prevention program' is 8.0%, solution program of stress which gives student by school score was very necessary. Therefore, school health education is formal and inefficient because school education focuses on an entrance exam, so middleㆍhigh school students decrease concern and interest about health education. Furthermore, reliance is gotten down about nurse-teacher who takes charge of school health, a charged person of school health education wants more chargeable health education staff. And a solution program of stress that gives students by school score was very necessary. According to active concern and planned, systematic school health education is necessary to give right health knowledge, health maintenanceㆍpromotion and setting of appropriate health education specialist is very urgent.