VERTECS: 6U CubeSat Mission to Study Star-Formation History by Observation of Visible Extragalactic Background Light

We describe an astronomical 6U CubeSat mission VERTECS (Visible Extragalactic background RadiaTion Exploration by CubeSat). The scientific purpose of VERTECS is to reveal star-formation history of the universe by observation of the extragalactic background light (EBL) in visible wavelengths. Earlier observations by sounding rockets and infrared astronomical satellites have shown that the near-infrared EBL is several times brighter than the integrated light of known galaxies. As candidates for the excess light, first-generation stars in the early universe or low-redshift intra-halo light have been proposed, but it has not been concluded. Since these objects are expected to show different emission spectra in visible wavelengths, precise visible observation is important to reveal the origin of excess light. Since detection sensitivity of the EBL is determined by the product of telescope aperture and field of view, a small wide-field telescope system enables the EBL observation with high sensitivity. In VERTECS mission, we develop a 6U CubeSat equipped with a 3U size telescope optimized for observation of visible EBL. The telescope is composed of lens optics and a CMOS sensor of 3k times 3k array format, which is designed to observe the sky in four photometric bands in 400-800nm. The satellite bus is composed of on-board computer (OBC), electric power system (EPS), communication (COM), attitude determination and control system (ACDS), and thermal structure. Design of OBC and EPS is based on heritage of CubeSats developed at Kyushu Institute of Technology, but deployable solar array wings is added to EPS to supply sufficient power to the VERTECS subsystems. In COM system, S-band is used for command uplink and X-band is used for high-speed downlink of large-size images captured by the telescope. Since the EBL measurement need discrimination of the background light from discrete foreground stars, VERTECS requires 10 arcseconds pointing stability (1 sigma) over 1 minute exposure. In 2022, VERTECS was selected for JAXA-Small Satellite Rush Program (JAXA-SMASH Program), a new program that encourages universities, private companies and JAXA to collaborate to realize small satellite missions utilizing commercial small launch opportunities, and to diversify transportation services in Japan. We have been working on functionality and interface teast using Bread Board Model (BBM), and enviroonmental tests by using the satellite structure thermal model. Launch of the satellite is planned in FY2025. We aim at developing the satellite and obtaining scientific results much more quickly than recent large astronomical-satellite missions

Development of a Compact Wide-Field Telescope to be Mounted on VERTECS

In recent years, CubeSat projects have initiated plans to conduct astronomical observations by deploying mission payloads. CubeSats present a promising solution for swiftly addressing critical challenges in astrophysics with flexibility. Within Cubeats, where both the bus system and mission payload occupy about half of the volume, there is a necessity to miniaturize mission equipment. The critical factor in astronomical observations, light-gathering ability, is determined not only by the aperture size but, more importantly for diffuse emission, by the optical throughput, i.e., the product of the aperture area and the observing solid angle. Consequently, even with a compact optical system, specializing in wide-field observations enables achieving light-gathering ability equivalent to that of a large-diameter telescope. Therefore, we propose equipping CubeSats with small, wide-field telescopes specialized for observing essential quantities in understanding the cosmic history of star formation, such as extragalactic background Light (EBL), and foreground components like zodiacal light and diffuse galactic light. Radiation from first-generation celestial bodies, which is challenging to detect due to their darkness in the distant universe, is included in the EBL in the visible to near-infrared wavelengths. Hence, wide-field survey observations in the visible and near-infrared play a crucial role in unraveling when, where, and how the first-generation stars were born in the early universe. However, current technology has not enabled the development of CubeSats with mechanisms capable of cooling infrared detectors to temperatures below a few tens of Kelvin. Therefore, we have designed an optical system focusing on the visible EBL. In the astronomical W6U CubeSat mission VERTECS (Visible Extragalactic background RadiaTion Exploration by CubeSat), we are developing a 3U mission payload, comprised of 1U-sized lens optics, camera modules, and baffles each. The lens optical system achieves a high throughput ( \u3e 10-6 m2 sr) by covering the entire field of view with 6 degrees by 6 degrees and each pixel with a field of view of 11 arcseconds by 11 arcseconds. The camera module uses a CMOS sensor with high quantum efficiency in visible light, featuring sufficiently low dark current noise (approximately 0.01 electrons per second at 269 K) and readout noise (approximately 2.6 electrons at 24 dB analog gain), compared to the photocurrent generated by the EBL and foreground photon noise. The baffle is designed to attenuate stray light from the Sun and Earth to negligible levels compared to the EBL signal. Additionally, a set of color filters divides the wavelength range of 400 to 800 nm into four bands. In our observation strategy, we capture 60-second exposure images by shifting the field of view by 3 degrees and perform photometry on the stacked images in the four bands. VERTECS project was selected in JAXA-Small Satellite Rush Program in 2022 and is currently advancing in satellite development, with a scheduled launch in FY2025. Thus far, a significant portion of the mission payload design meets the required specifications, and progress is underway towards the fabrication of the engineering model. In this presentation, we will report on the progress of our optical telescope development, our strategy for visible EBL observations, and our future plans

Synthesis and Evaluation of 1,3a,6a-triazapentalene (TAP)-bonded system

A method of synthesizing a directly connected 1,3a,6a-triazapentalene (TAP) ring system as a linearly bonded aromatic system with a planar form was established. Various TAP-dimers and a 2-alkyl-TAP-trimer were synthesized and their fluorescence properties were evaluated. Although the direct connection of the TAP ring with other TAP rings did not affect the fluorescence properties in diluted solvent, TAP-dimers showed unique fluorescence properties derived from the aggregation state under highly concentrated conditions. In particular, TAP-dimer 5f showed aggregation-induced emission in highly concentrated solution, and 5b showed typical mechanochromic fluorescence in the solid state despite their compact molecular size

An Electrical Power System Development for VERTECS: A 6U CubeSat Mission for Observation the Extragalactic Background Light

This paper focuses on an overview of the electrical power system (EPS) implemented in the Visible extragalactic background radiation exploration by CubeSat (VERTECS), a 6U CubeSat developed by a collaboration of the Kyushu institute of technology (Kyutech), JAXA, universities, and companies. Its mission aims to reveal the star-formation history of the universe through observations of the extragalactic background light (EBL) in visible wavelength. This article presents the three primary functions of the EPS in VERTECS design (i.e., power source, energy storage, and power control) in detail, as well as the verification of the system by the breadboard model (BBM). Numerous factors are considered in designing and developing the power source for VERTECS. The keys of the design consist of end-of-life (EOL) requirements, the selection of solar cell type, the solar array mass and area, power input, and power consumption. Most designs of the EPS have flight heritage from previous satellites developed at Kyutech. Given the application of high-throughput optics in the payload for efficient handling and processing of large amounts of light, significant updates are required in the EPS design, particularly concerning power consumption. Consequently, the design of solar panels has been enhanced by increasing the two deployable solar panels to serve more power for the mission. The triple junction GaAs solar panels with five solar panels are utilized for VERTECS. There are three panels mounted to the satellite structure and two panels deployed. Secondly, VERTECS adopts the Li-ion battery as the energy storage due to its superior capacity-weight ratio. The battery screening approaches are essential to ensure the operational efficiency of the battery throughout the mission in space. The battery screening consists of physical and cell screenings conducted before and after vacuum and vibration testing. After the screening, the batteries are selected according to the appropriate and standard criteria. Regarding the power control, the peripheral interface controller (PIC), known as the Reset PIC, controls the electrical power supply for VERTECS satellite system. Its primary function is to reset the power supply of other microcontrollers in the event of failure. In the design to mitigate potential issues of the Reset PIC, its programming code is straightforward, and a simple external watchdog is provided to facilitate recovery. Furthermore, functional testing of the BBM is conducted to verify the EPS. It includes verifying voltage ratings, overcurrent protection, and DC/DC converter efficiency

Selective Bias: Asian Americans, Test Scores, and Holistic Admissions

Selective Bias: Asian Americans, Test Scores, and Holistic Admissions evaluates the common arguments made by affirmative action critics and Students for Fair Admissions, which is suing Harvard University and has lawsuits pending against the University of North Carolina and the University of Texas at Austin over their admissions practices. The report finds no strong evidence of discrimination against Asian American applicants in admissions to highly selective colleges

Imposing a Deadline on the IRS: Artificial Intelligence Tries to Beat \u27Starcraft\u27 While the IRS Tries to Regulate Virtual Currency

Virtual currencies demanded serious attention in 2017 due to public interest, media attention, and investor appetite. With this increased attention on virtual currencies comes significant business, legal, and tax risks. This article serves as a launching pad for those tax risks, and attempts to predict how the IRS will react. By focusing on the IRS’s treatment of virtual currency as property, as well as discussing other tax issues like Foreign Bank Account Reporting (FBAR) compliance and like-kind exchanges under Internal Revenue Code section 1031, this article highlights the difficulty the IRS will have in regulating the ever-expanding world of virtual currencies and crypto assets. While no silver bullet is currently available to the IRS, allowing virtual currencies to be classified as property ends up creating more questions than it does answers. This article explores those questions