Conceptual Design of the NISS onboard NEXTSat-1

Jeong, Wooju; Park, Sung‐Joon; Park, Kwijong; Lee, Dae-Hee; Pyo, Jeonghyun; Moon, Byung-Kwon; Park, Young-Sik; Kim, Il-Joong; Park, Won-Kee; Lee, Duk-Hang; Park, Chan; Ko, Kyeongyeon; Matsumoto, Toshio; Takeyama, Norihide; Enokuchi, Akito; Shin, G Goto; Chae, Jang-Soo; Nam, Uk-Won

doi:10.5140/jass.2014.31.1.83

Cited by 11 publications

(4 citation statements)

References 20 publications

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“…The orbit is Sun-synchronous at 575 km above ground and 10:30-22:30 local time (LT). The main payload is the Near-infrared Imaging Spectrometer for Star formation history (NISS), which takes images of the universe in the near-infrared spectral range (Jeong et al, 2014). The secondary payload, the Instrument for the Study of Space Storms (ISSS), provides information on high-energy particles (Seo et al, 2015(Seo et al, , 2021Sohn et al, 2018) and parameters of background cold ionospheric plasma (Lee et al, 2018).…”

Section: Instruments and Data Processing Methodsmentioning

confidence: 99%

Multi‐Year Statistics of LEO Energetic Electrons as Observed by the Korean NextSat‐1

et al. 2021

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Monitoring the Earth's radiation belt by Low-Earth-Orbit (LEO) satellites has a long history and complemented observations near the high-altitude equatorial plane. However, most of the previous LEO missions suffered from limitations in energy resolution, energy range, L-shell coverage, or the mission lifetime, which leave room for further improvement in this topic. Here we present multi-year (January 2019~February 2021) observations of energetic (0.03 MeV~1.8 MeV) electrons by the Korean NextSat-1 (altitude~575 km) with high energy resolution (0.006-0.4 MeV) and seamless L-shell coverage. For <80 keV electrons, the slot-region outer edge moves inward with increasing geomagnetic activity, which agrees with previous Van Allen Probes reports. The behavior is more conspicuous for lower-energy electrons. Latitudinal profiles of outer-belt electron flux are smoother equatorward of the geosynchronous footprint latitudes (|MLAT|~66 o ) than poleward. The NextSat-1 electron flux is positively correlated to geosynchronous observations, with the coefficient generally higher for higher electron energies. Also, both the geosynchronous and NextSat-1 data exhibit similar spectral indices close to -3 in the log-log space. All these results complement and expand previous knowledge on energetic electrons. The main findings are discussed in the context of existing literature.

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Section: Instruments and Data Processing Methodsmentioning

confidence: 99%

Multi‐Year Statistics of LEO Energetic Electrons as Observed by the Korean NextSat‐1

et al. 2021

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“…The Korea Astronomy and Space Science Institute (KASI) has been developing both ground- (Yuk et al 2010;Oh et al 2014) and space-based (Jeong et al 2014) astronomical instrumentation. Recently, the Korea lunar exploration project has progressed to the development of a lunar probe and studies of the lunar mineralogy are planned (Lee et al 2017;Kim et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the KASI Detector Performance Test System Using an Andor iKon M CCD Camera

Kim

Park

et al. 2018

Journal of Astronomy and Space Sciences

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The characterization of detectors installed in space- and ground-based instruments is important to evaluate the system performance. We report the development of a detector performance test system for astronomical applications using the Andor iKon M CCD camera. The performance test system consists of a light source, monochromator, integrating sphere, and power meters. We adopted the Czerny–Tuner monochromator with three ruled gratings and one mirror, which covers a spectral range of 200–9,000 nm with a spectral resolution of ~1 nm in the visible region. Various detector characteristics, such as the quantum efficiency, sensitivity, and noise, can be measured in wide wavelength ranges from the visible to mid-infrared regions. We evaluated the Korea Astronomy and Space Science Institute (KASI) detector performance test system by using the performance verification of the Andor iKon-M CCD camera. The test procedure includes measurements of the conversion gain (2.86 e−/ADU), full well capacity (130 K e−), nonlinearity, and pixel defects. We also estimated the read noise, dark current, and quantum efficiency as a function of the temperature. The lowest measured read noise is 12 e−. The dark current at 223 K was determined to be 7 e−/s/pix and its doubling temperature is 5.3°C ± 0.2°C at an activation energy of 0.6 eV. The maximum quantum efficiency at 223 K was estimated to be 93 % ± 2 %. We proved that the quantum efficiency is sensitive to the operating temperature. It varies up to 5 % in the visible region, while the variation increases to 30 % in the near-infrared region. Based on the comparison of our results with the test report by the vendor, we conclude that our performance test results are consistent with those from the vendor considering the test environment. We also confirmed that the KASI detector performance test system is reliable and our measurement method and analysis are accurate.

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“…In contrast, these problems do not exist in obstruction-free, off-axis reflective systems because the optical paths are all in free space and, thus, are not subject to obstruction. They can be applied to a payload on microsatellites or sounding rockets for wide-field mid-IR observations, e.g., diffuse interstellar media or cosmic background radiation in the mid-and far-IR wavelength regimes [4][5][6][7]. In addition, off-axis reflective systems can be adopted to a fore-optics system for ground-based astronomical IR spectrographs [8].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of electroless nickel plated aluminum freeform mirror for an infrared off-axis telescope

et al. 2015

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Freeform mirrors can be readily fabricated by a single point diamond turning (SPDT) machine. However, this machining process often leaves mid-frequency errors (MFEs) that generate undesirable diffraction effects and stray light. In this work, we propose a novel thin electroless nickel plating procedure to remove MFE on freeform surfaces. The proposed procedure has a distinct advantage over a typical thick plating method in that the machining process can be endlessly repeated until the designed mirror surface is obtained. This is of great importance because the sophisticated surface of a freeform mirror cannot be optimized by a typical SPDT machining process, which can be repeated only several times before the limited thickness of the nickel plating is consumed. We will also describe the baking process of a plated mirror to improve the hardness of the mirror surface, which is crucial for minimizing the degradation of that mirror surface that occurs during the polishing process. During the whole proposed process, the changes in surface figures and textures are monitored and cross checked by two different types of measurements, as well as by an interference pattern test. The experimental results indicate that the proposed thin electroless nickel plating procedure is very simple but powerful for removing MFEs on freeform mirror surfaces.

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Conceptual Design of the NISS onboard NEXTSat-1

Cited by 11 publications

References 20 publications

Multi‐Year Statistics of LEO Energetic Electrons as Observed by the Korean NextSat‐1

Multi‐Year Statistics of LEO Energetic Electrons as Observed by the Korean NextSat‐1

Evaluation of the KASI Detector Performance Test System Using an Andor iKon M CCD Camera

Fabrication of electroless nickel plated aluminum freeform mirror for an infrared off-axis telescope

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