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21.
The Upgraded CARISMA Magnetometer Array in the THEMIS Era 总被引:1,自引:0,他引:1
I. R. Mann D. K. Milling I. J. Rae L. G. Ozeke A. Kale Z. C. Kale K. R. Murphy A. Parent M. Usanova D. M. Pahud E.-A. Lee V. Amalraj D. D. Wallis V. Angelopoulos K.-H. Glassmeier C. T. Russell H.-U. Auster H. J. Singer 《Space Science Reviews》2008,141(1-4):413-451
This review describes the infrastructure and capabilities of the expanded and upgraded Canadian Array for Realtime InvestigationS of Magnetic Activity (CARISMA) magnetometer array in the era of the THEMIS mission. Formerly operated as the Canadian Auroral Network for the OPEN Program Unified Study (CANOPUS) magnetometer array until 2003, CARISMA capabilities have been extended with the deployment of additional fluxgate magnetometer stations (to a total of 28), the upgrading of the fluxgate magnetometer cadence to a standard data product of 1 sample/s (raw sampled 8 samples/s data stream available on request), and the deployment of a new network of 8 pairs of induction coils (100 samples per second). CARISMA data, GPS-timed and backed up at remote field stations, is collected using Very Small Aperture Terminal (VSAT) satellite internet in real-time providing a real-time monitor for magnetic activity on a continent-wide scale. Operating under the magnetic footprint of the THEMIS probes, data from 5 CARISMA stations at 29–30 samples/s also forms part of the formal THEMIS ground-based observatory (GBO) data-stream. In addition to technical details, in this review we also outline some of the scientific capabilities of the CARISMA array for addressing all three of the scientific objectives of the THEMIS mission, namely: 1. Onset and evolution of the macroscale substorm instability, 2. Production of storm-time MeV electrons, and 3. Control of the solar wind-magnetosphere coupling by the bow shock, magnetosheath, and magnetopause. We further discuss some of the compelling questions related to these three THEMIS mission science objectives which can be addressed with CARISMA. 相似文献
22.
Siwoo Kim Byeong-Un Jo Eun-Jung Choi Sungki Cho Jaemyung Ahn 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(6):1844-1858
This paper proposes a procedure for managing the risk of reentering space objects and risk assessment methodologies used for the process. The proposed procedure comprises three phases encompassing the whole reentry stages of space objects. Mathematical models for assessing the impact risk of the reentering space objects by utilizing the information available during different risk management phases and the recommended risk analysis results for public communication are presented. The concept of the conditional casualty expectation is proposed as the metric representing the reentry risk and the method to compute its profile is introduced. A case study on the risk management procedure with the dataset on an actual reentry event is conducted to demonstrate the efficacy of the proposed procedure. 相似文献
23.
Dong-Young Rew Min-Jea Tahk Hangju Cho 《IEEE transactions on aerospace and electronic systems》1996,32(3):1107-1115
Stability characteristics of proportional navigation (PN) guidance are analyzed by using the short-time stability criterion which is extended here to accommodate time-varying state weights and time-varying bounds of the state norm. As short-time stability is defined over a specified time interval, its application to the stability analysis of a homing guidance loop that operates up to a finite time gives more accurate results than previous studies. Furthermore, within the framework of short-time stability, zero effort miss and acceleration command, which are the most important variables determining guidance performance, can be directly related with guidance loop stability. An application to a PN guidance loop with a 1st-order missile/autopilot time lag shows that the stability condition based on short-time stability is less conservative than the previous results based on hyperstability and Popov stability 相似文献
24.
Il-Hyun Cho Young-Sil Kwak Katsuhide Marubashi Yeon-Han Kim Young-Deuk Park Heon-Young Chang 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
We explore a possibility that the daily sea-level pressure (SLP) over South Korea responds to the high-speed solar wind event. This is of interest in two aspects: first, if there is a statistical association this can be another piece of evidence showing that various meteorological observables indeed respond to variations in the interplanetary environment. Second, this can be a very crucial observational constraint since most models proposed so far are expected to preferentially work in higher latitude regions than the low latitude region studied here. We have examined daily solar wind speed V, daily SLP difference ΔSLP, and daily log(BV2) using the superposed epoch analysis in which the key date is set such that the daily solar wind speed exceeds 800 km s−1. We find that the daily ΔSLP averaged out of 12 events reaches its peak at day +1 and gradually decreases back to its normal level. The amount of positive deviation of ΔSLP is +2.5 hPa. The duration of deviation is a few days. We also find that ΔSLP is well correlated with both the speed of solar wind and log(BV2). The obtained linear correlation coefficients and chance probabilities with one-day lag for two cases are r ? 0.81 with P > 99.9%, and r ? 0.84 with P > 99.9%, respectively. We conclude by briefly discussing future direction to pursue. 相似文献
25.
V. Angelopoulos D. Sibeck C. W. Carlson J. P. McFadden D. Larson R. P. Lin J. W. Bonnell F. S. Mozer R. Ergun C. Cully K. H. Glassmeier U. Auster A. Roux O. LeContel S. Frey T. Phan S. Mende H. Frey E. Donovan C. T. Russell R. Strangeway J. Liu I. Mann J. Rae J. Raeder X. Li W. Liu H. J. Singer V. A. Sergeev S. Apatenkov G. Parks M. Fillingim J. Sigwarth 《Space Science Reviews》2008,141(1-4):453-476
THEMIS was launched on February 17, 2007 to determine the trigger and large-scale evolution of substorms. During the first seven months of the mission the five satellites coasted near their injection orbit to avoid differential precession in anticipation of orbit placement, which started in September 2007 and led to a commencement of the baseline mission in December 2007. During the coast phase the probes were put into a string-of-pearls configuration at 100 s of km to 2 RE along-track separations, which provided a unique view of the magnetosphere and enabled an unprecedented dataset in anticipation of the first tail season. In this paper we describe the first THEMIS substorm observations, captured during instrument commissioning on March 23, 2007. THEMIS measured the rapid expansion of the plasma sheet at a speed that is commensurate with the simultaneous expansion of the auroras on the ground. These are the first unequivocal observations of the rapid westward expansion process in space and on the ground. Aided by the remote sensing technique at energetic particle boundaries and combined with ancillary measurements and MHD simulations, they allow determination and mapping of space currents. These measurements show the power of the THEMIS instrumentation in the tail and the radiation belts. We also present THEMIS Flux Transfer Events (FTE) observations at the magnetopause, which demonstrate the importance of multi-point observations there and the quality of the THEMIS instrumentation in that region of space. 相似文献
26.
Sensitivity analyses of satellite propulsion components with their thermal modelling 总被引:1,自引:0,他引:1
Cho Young Han Jae Ho You Kyun Ho Lee Hui Kyung Kim Sung Nam Lee 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
Performing the sensitivity analyses of the contact conduction and the position of thermostat on the basis of the thermal model established, the study of thermal design is accomplished for the preparation of possible mechanical interface change of the satellite propulsion system depending on the satellite system design. A relatively simple thermal model is taken into consideration for the convenience of the analysis. A variety of the spacecraft bus voltages and the contact resistances are examined as well as the position of thermostat on propulsion components. As a consequence, even though the mechanical interface condition is changed on the same module, the successful thermal design could be achieved if we design the heater to have sufficiently large power with reference to the heritage value of contact resistance. Besides the reasonable performance on the thermal control is assured with the thermostat location errors, if the uncertainty in the position of thermostat is not quite large when assembling tank module. 相似文献
27.
Young-Jin Park Kwan-Ho Kim Sung-Bae Cho Dong-Wook Yoo Dong-Gi Youn Young-Kyung Jeong 《Aerospace and Electronic Systems Magazine, IEEE》2004,19(10):3-6
A ground penetrating radar (GPR) using short-pulse is developed to detect small and shallow metal objects buried underground. A bistatic mode in which the GPR system uses separate transmitting and receiving antennas is applied. A modified fat dipole antenna is developed for the transmitting and receiving antennas. The prototype of the system is tested in the real environment and 2D visualization of raw data is achieved. We show that the developed system has a good ability to detect underground metal objects, and even small targets of several centimeters. 相似文献
28.
Accomplishment of multi-utility spacecraft charging analysis tool (MUSCAT) and its future evolution 总被引:1,自引:0,他引:1
Shinji Hatta Takanobu Muranaka Jeongho Kim Satoshi Hosoda Kouichirou Ikeda Naomi Kurahara Mengu Cho Hiroko O. Ueda Kiyokazu Koga Tateo Goka 《Acta Astronautica》2009,64(5-6):495-500
(MUSCAT) is a high value computation tool for analyzing spacecraft–plasma interaction, whose typical example is charging–arcing issue, corresponding to spacecrafts in LEO, GEO and PEO. JAXA and Kyushu Institute of Technology (KIT) started the development as a joint project in November 2004 and the final version of MUSCAT was released in March 2007. The final version includes many important features to simulate spacecraft–plasma interaction and the features can be separated into four parts. The first part is its GUI named “Vineyard”. By using Vineyard, MUSCAT users can build a satellite model including not only its geometry but also material properties of the surface. As for the second part, MUSCAT includes many kinds of effects derived from space plasma environment as well as electrical functions of spacecraft. For the third part, MUSCAT can work on parallel workstation with multi-CPU. The last feature is that the computation result by MUSCAT was thoroughly validated by experiments in plasma chamber. The numerical result shows very good agreement with the code validation experiment. We also conducted trial computation of charging analysis on Greenhouse gases Observing Satellite (GOSAT) with MUSCAT. One purpose of the computation was prediction of charging status of GOSAT for the real satellite design in combination with the ground test. The other is performance assessment of MUSCAT. After the joint project, expansion and maintenance of MUSCAT will be carried out by “MUSCAT Space Engineering Ltd” which is a new enterprise made of the development team. In future we will try to conduct MUSCAT computation for various spacecrafts and also try to add useful function such as 3D CAD compatibility. 相似文献