A satellite placed in space is constantly affected by the space environment, resulting in various impacts from temporary faults to permanent failures depending on factors such as satellite orbit, solar and geomagnetic activities, satellite local time, and satellite construction material. Anomaly events commonly occur during periods of high geomagnetic activity that also trigger plasma variation in the low Earth orbit (LEO) environment. In this study, we diagnosed anomalies in LEO satellites using electron data from the Medium Energy Proton and Electron Detector onboard the National Oceanic and Atmospheric Administration (NOAA)-15 satellite. In addition, we analyzed the fluctuation of electron flux in association with geomagnetic disturbances 3 days before and after the anomaly day. We selected 20 LEO anomaly cases registered in the Satellite News Digest database for the years 2000-2008. Satellite local time, an important parameter for anomaly diagnosis, was determined using propagated two-line element data in the SGP4 simplified general perturbation model to calculate the longitude of the ascending node of the satellite through the position and velocity vectors. The results showed that the majority of LEO satellite anomalies are linked to low-energy electron fluxes of 30-100 keV and magnetic perturbations that had a higher correlation coefficient (~ 90%) on the day of the anomaly. The mean local time calculation for the anomaly day with respect to the nighttime migration of energetic electrons revealed that the majority of anomalies (65%) occurred on the night side of Earth during the duskto-dawn sector of magnetic local time. which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
The "Space Seeds for Asian Future (SSAF)" program is one of the activities of the "Kibo-ABC" initiative under the Asia-Pacific Regional Space Agency Forum (APRSAF). The program intends to promote understanding, and to give regional space agencies experience in the utilization of the Japanese Experiment Module, "Kibo", of the International Space Station (ISS). It also aims to provide young people in the Asia-Pacific region with opportunities to learn about leading edge sciences through their participations in experiments under peculiar space conditions, including microgravity. Students from Indonesia, Malaysia, Thailand and Vietnam participated in the SSAF2010-2011 program. As part of this program seeds from each of these nations were flown to the ISS and kept in the Kibo Module. These seeds were then returned to Earth where they were germinated and compared to control seed not flown in space. This experiment involved researchers, students and the general public. In the SSAF2013 program, there are plans to cultivate seeds indigenous to Asia in the Kibo/ISS facilities. The plan is to send Azuki bean (Vigna angularis) to Kibo, and observe the growth of their seedlings under dark conditions. Members of the Kibo-ABC initiative are collaborating in the preparation of the seed germination testing procedures, following which many people, including children, students and researchers, are expected to participate in the program.
This study aims to integrate hadith, astronomy and sociology studies in examining the implementation of Hijri calendar unification through a multidisciplinary approach. The Hijri calendar is based on the astronomical phenomena of the earth-moon-sun system and should refer to the provisions of Islamic law or fiqh to be implemented in worship. For the preparation of a good Hijri calendar, agreement on criteria, date line, and authority is necessary. Furthermore, agreement on criteria requires a valid argument based on astronomical studies. An agreement on the implementing region boundaries is necessary due to the round earth and the hilal [crescent moon] cannot be observed simultaneously anywhere. It is also needed to resolve unavoidable differences, specifically in the appearance of the hilal and in schools of Islamic law. The problems to be solved are as follows: What is the strategy for implementing Hijri calendar unification? This study is based on a review of hadith and fiqh literature, analysis of astronomical data related to criteria, and experiences of Indonesia and Islamic countries regarding the Hijri calendar unification. The results show that implementing the Hijri calendar unification through the three approaches above can be carried out and accelerated.Contribution: This study contributes to showing the results of a multidisciplinary approach in the problem of implementation of the new Ministers of Religious Affairs of Brunei Darussalam, Indonesia, Malaysia, and Singapore (MABIMS) criteria towards unification of the Hijri calendar.
Since the discovery of the radiation belt decades ago, there still remain some fundamental questions as to which one is the mechanism responsible for the acceleration of electrons. Groundbased Pc5 magnetic pulsation during the process of increasing of 2-MeV electron fluxes has been analyzed. First, a filter bandpass in the period range of 150-600 seconds has been used to localize the Pc5 waves. Second, we then applied a wavelet transform procedure, whereby the Morlet function as a mother wavelet was selected to analyze Pc5 wave packets. First, we show that dynamic pressure of solar wind controls the power of Pc5 magnetic pulsations. Second, by performing a cross-spectrum analysis of Pc5 wavelet during electron radiation belts we show that the wavelet power of Pc5 magnetic pulsations which is associated with a maximum wavelet cross spectrum show a similar change of Pc5 pulsations occurs during radiation belt events. Increasing of electron fluxes which is initiated by the presence of large power of Pc5 magnetic pulsations has been observed. This indicates that Pc5 magnetic pulsations could play a role in the acceleration and transport mechanism of the electron radiation belt. Also, 4-5 days from the beginning of increasing of electron fluxes we observed globally, a depression in the power of Pc5 magnetic pulsations as well as a monotonically decreasing of the solar wind dynamic pressure. On the other hand, during the end period of the electron belt, we also observed a sudden increasing of Pc5 power. We suggest that during the expansion periode of the outer electron radiation belt outward to interplanetary electron belt pressure that will reduce the solar wind dynamic pressure and consequently a decrease occurs in the power of Pc5 magnetic pulsation. And, in the end period of the electron radiation belt the electron fluxes back to its normal level and consequently a sudden increase of the Pc5 solar wind dynamic pressure occurs and that sudden increase also drives the sudden increasing power of Pc5 magnetic pulsations.
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