• Journal of Space Technology and Applications
• /
• v.3 no.2
• /
• pp.118-143
• /
• 2023

Space is becoming more commercialized. Despite of its delayed start-up, space activities in Korea are attracting more nation-wide supports from both investors and government. May 25, 2023, KSLV II, also called Nuri, successfully transported, and inserted seven satellites to a sun-synchronous orbit of 550 km altitude. However, Starlink has over 4,000 satellites around this altitude for its commercial activities. Hence, it is necessary for us to constantly monitor the collision risks of these satellites against resident space objects including Starlink. Here we report a quantitative research output regarding the conjunctions, particularly between the Nuri satellites and Starlink. Our calculation shows that, on average, three times everyday, the Nuri satellites encounter Starlink within 1 km distance with the probability of collision higher than 1.0E-5. A comparative study with KOMPSAT-5, also called Arirang-5, shows that its distance of closest approach distribution significantly differs from those of Nuri satellites. We also report a quantitative analysis of collision-avoiding maneuver cost of Starlink satellites and a strategy for Korea, being a delayed starter, to speed up to position itself in the space leading countries. We used the AstroOne program for analyses and compared its output with that of Socrates Plus of Celestrak. The two line element data was used for computation.

• 시스템엔지니어링워크숍
• /
• s.7
• /
• pp.75-78
• /
• 2006

• The Korean Journal of Air & Space Law and Policy
• /
• v.29 no.2
• /
• pp.205-237
• /
• 2014

Last 50 years there were a lot of space subjects launched by space activities of many states and these activities also had created tremendous, significant space debris contaminating the environment of outer space. The large number of space debris which are surrounding the earth have the serious possibilities of destroying a satellite or causing huge threat to the space vehicles. For example, Chinese anti-satellite missile test was conducted by China on January 11, 2007. As a consequence a Chinese weather satellite was destroyed by a kinetic kill vehicle traveling with a speed of 8 km/s in the opposite direction. Anti-satellite missile tests like this,contribute to the formation of enormous orbital space debris which can remain in orbit for many years and could interfere with future space activity (Kessler Syndrome). The test is the largest recorded creation of space debris in history with at least 2,317 pieces of trackable size (golf ball size and larger) and an estimated 150,000 debris particles and more. Several nations responded negatively to the test and highlighted the serious consequences of engaging in the militarization of space. The timing and occasion aroused the suspicion of its demonstration of anti-satellite (ASAT) capabilities following the Chinese test of an ASAT system in 2007 destroying a satellite but creating significant space debris. Therefore this breakup seemed to serve as a momentum of the UN Space Debris Mitigation Guidelines and the background of the EU initiatives for the International Code of Conduct for Outer Space Activities. The UN Space Debris Mitigation Guidelines thus adopted contain many technical elements that all the States involved in the outer space activities are expected to observe to produce least space debris from the moment of design of their launchers and satellites until the end of satellite life. Although the norms are on the voluntary basis which is normal in the current international space law environment where any attempt to formulate binding international rules has to face opposition and sometimes unnecessary screening from many corners of numerous countries. Nevertheless, because of common concerns of space-faring countries, the Guidelines could be adopted smoothly and are believed faithfully followed by most countries. It is a rare success story of international cooperation in the area of outer space. The EU has proposed an International Code of Conduct for Outer Space Activities as a transparency and confidence-building measure. It is designed to enhance the safety, security and sustainability of activities in outer space. The purpose of the Code to reduce the space debris, to allow exchange of the information on the space activities, and to protect the space objects through safety and security. Of the space issues, the space debris reduction and the space traffic management require some urgent attention. But the current legal instruments of the outer space do not have any binding rules to be applied thereto despite the incresing activities on the outer space. We need to start somewhere sometime soon before it's too late with the chaotic situation. In this article, with a view point of this problem, focused on the the Chinese test of an ASAT system in 2007 destroying a satellite but creating significant space debris and tried to analyse the issues of space debris reduction.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.41 no.8
• /
• pp.619-624
• /
• 2013

To predict the probabilistic service life, statistical factors should be included to consider the uncertainty of parameters. Generally the probabilistic analysis is one of the common methods to account the uncertainty of parameters on the structural failure. In order to apply probabilistic analysis on the deterministic life analysis, it would be necessary to introduce Probability of Failure(PoF) and conduct risk assessment. In this work, we have studied probabilistic risk assessment of aircraft structures by using PoF approach. To achieve this goal, the Bayesian method was utilized to model PoF estimation since this method is known as the proper method to express the uncertainty of parameters. A series of proof tests were also conducted in order to verify the result of PoF estimation. The results from this efforts showed that the PoF estimation model can calculate quantitatively the value of PoF. Furthermore effectiveness of risk assessment approach for the aircraft structures was also demonstrated.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2010.10a
• /
• pp.199-202
• /
• 2010

우주발사체를 운용하는 발사장은 화재나 폭발의 위험에 많이 노출 되어 있다. 발사장은 비행시험전 발사체의 모든 상태를 점검 하고, 비행시험을 수행하는 곳이다. 또, 유사시에는 대량의 산화제와 연료가 누출 되어 화재 및 폭발사고로 이어질 가능성이 있는 곳이다. 나로우주센터에서 운용하는 우주발사체 나로호는 연료로 케로신(kerosene)을 사용하고, 산화제로 액화산소(LOX)를 사용한다. 발사대의 소화설비는 화재발생시 원격제어를 통해서 소화수와 소화약제를 분사하여 진화하는 방식으로 구성 되어 있다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2009.04a
• /
• pp.1047-1048
• /
• 2009

인공위성은 전자와 양자들로 인한 방사현상, 위치에 따른 온도변화 및 진공에 의한 영향 등 극한 우주 환경에서 동작하므로 항상 위험에 노출되어 있다. 특히 저궤도 관측위성은 지구와의 통신이 제한적이기 때문에 위성에 문제가 발생할 경우 신속한 대응이 어려워 질 수 있다. 따라서 위성을 설계할 때에 다양한 오류 상황을 예상하고 이에 대비하여 비상 시 운영 가능한 방안을 마련해야 한다. 본 논문에서는 소프트웨어적인 비상 운영 방법을 제안한다. 위성에서 발생하는 오류를 기록하여 지상으로 전달하는 방법과 긴급한 문제가 발생 하였을 경우 주요 파라 미터를 확인하여 위성에서 조치를 취할 수 있는 방법에 대해 소개하도록 하겠다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.41 no.2
• /
• pp.164-171
• /
• 2013

Since plenty of spacecrafts were launched in space after 1957, the number of space debris has been increased. According to the JSpOC, the number of space debris which diameter is bigger than 10 cm are more than 22,000. Recently there were two critical events. Which one is that China shot down their satellite using missile and the other is that two satellite, Iridium and Cosmos 2251, collied. Space environment in low-earth orbit has been severe. JSpOC analyzes the collision risk between 15,000 space debris and all operation satellites and then they send CSM to the satellite operator to utilize its orbital information if collision risk might be occurred. This paper analyzes the CSM orbit data by comparing with KOMPSAT-2 precise orbit data and shows conjunction assessment results.

• The Korean Journal of Air & Space Law and Policy
• /
• v.19 no.2
• /
• pp.163-177
• /
• 2004

Wenn man das fahrl${\"{a}}$ssige Begehungsdelikt in Bezug auf ein Niveau eines Risiko der objektiv vorhandenen tatbestandlichen Erfolgsm${\"{o}}$glichkeit und auf die n${\"{o}}$tige Sorgfaltspflicht, die die T${\"{a}}$ter nimmt, um das solches Risiko abzuhalten, berucksichtigt, ergibt sich der spezielle Fall selten bei der Person, mit dem hoch-gefahrlichen Berufszweig besch${\"{a}}$ftigt ist, auf den die bestehende Allgemeine-Theorie ${\"{u}}$ber das gafahrl${\"{a}}$ssige Begehungsdelikt gleichm${\"{a}}$ssig unanwendbar ist. Bez${\"{u}}$glich des Piloten des Milit${\"{a}}$rflugzeug ergibt sich oftmals ein bestmmter Fall, die die KontroIIe des Risiko gesch${\"{a}}$ftlich uber sein eigenes pers${\"{o}}$nliches Ermessen geht, und er nimmt die Pflicht, die notwendige milit${\"{a}}$rische Zielsetzung zuerst vor allem zu ber${\"{u}}$cksichtigen, wenn auch technisch, klimatisch und umstandehalber ein normales Niveau von Risiko ${\"{u}}$bersteigt wird und zugleich ein bedenkliches hoches Risiko mit sich gebracht wird. Aus diesem Anla${\beta}$ kann man folgem, da${\beta}$ der Pilot des Milit${\"{a}}$rflugzeug ein besonderer Fall ist, auf den die Kriterien in Bezug auf das Gebiet der Regel ${\"{u}}$ber das fahrl${\"{a}}$ssige Begehungsdelikt gleichm${\"{a}}$ssig unanwendbar sind. Und weil die Vermehrung der Gefahr des Flugzeug sofort an die Vermehrung der Gefahr seines eigenen Leben angeschlossen wird und daher es eine M${\"{o}}$glichkeit gibt, da${\beta}$ der Pilot dem Resultat eines Gefahr zum ersten Opfer f${\"{a}}$llt, ist die Regelung in der Punkt der Generalpr${\"{a}}$vention gegen das fahrl${\"{a}}$ssige Begehungsdelikt sinnlos. Und auch muB die militarpolitische Punkt, die Piloten des Milit${\"{a}}$rflugzeug gem${\"{a}}$${\beta}$ dem notwendigen Ausma${\beta}$ auszubilden und das Ausma${\beta}$ zu behalten, aktuell berucksichtigt werden.

• The Optical Journal
• /
• s.142
• /
• pp.23-26
• /
• 2012

천문학계는 더 멀리 있는 천체나 더 어두운 천체를 관측하기 위하여 부단히 노력하고 있다. 이로써 우리 주위를 맴돌고 있는 위험한 물체를 사전에 찾아내어 대비하고 외계에 생명체가 있는지 조사하며 우주의 전체 모습과 역사를 파악하고자 한다. 이를 위하여 더욱 더 크고 성능 좋은 망원경을 개발해 왔다. 광학망원경 분야에서는 1990년대에 구경 8~10m급 망원경을 건설하였으며, 이후 차세대 거대망원경을 개발하고 있다. 망원경 분야는 미터 급의 초대형 광학의 수준을 넘어 이제는 수십 미터 급의 거대 광학으로 발전하고 있다.

• The Safety technology
• /
• no.202
• /
• pp.21-23
• /
• 2014

지난 1898년 1월 5일 개국한 강릉우체국. 이처럼 오랜 역사를 갖고 있는 강릉우체국은 지역 주민들에게 보다 나은 우정서비스를 제공하기 위해 새단장을 준비하고 있다. 구시가지에서 벗어나 강릉역 인근에 새롭게 터를 잡고 주민 밀착형 행정서비스를 지원할 예정인 것이다. 오늘의 주인공이 바로 강릉우체국의 새로운 사옥을 건립하고 있는 (주)우주다. 이곳 현장은 지난해 6월 차공 이후 현재가지 무재해를 달성할 만큼 철두철미한 안전관리를 전개하고 있다. 지난 8월 안전보건공단으로부터 '위험성평가 우수사업장'으로 인정받았다는 것에서 이곳의 안전관리 우수성을 엿볼 수 있다. 중소규모 건설현장의 안전관리 모범사례를 여실히 보여주고 있는 이곳 현장을 찾아가 봤다.