Discovery of the Inner Ring around PSR B1509-58

A Chandra study of pulsar wind nebula around the young energetic pulsar PSR B1509-58 is presented. The high resolution X-ray image with total exposure time of 190 ks reveals a ring like feature 10'' apart from the pulsar. This feature is analogous to the inner ring seen in the Crab nebula and thus may correspond to a wind termination shock. The shock radius enables us to constrain the wind magnetization, sigma>= 0.01. The obtained sigma is one order of magnitude larger than that of the Crab nebula. In the pulsar vicinity, the southern jet appears to extend beyond the wind termination shock, in contrast to the narrow jet of the Crab. The revealed morphology of the broad jet is coincident with the recently proposed theoretical model in which a magnetic hoop stress diverts and squeezes the post-shock equatorial flow towards the poloidal direction generating a jet.Comment: 8 pages, 5 figures, 2 tables, submitted to PAS

6U CubeSat for Ultraviolet Time-Domain Astronomy

A wide-field ultraviolet observatory for time-domain astronomy utilizing 6U CubeSat is presented. Ultraviolet waveband is one of the unexplored fields in astronomy. Potential targets are short duration transient sources in UV-band: early-phase emission from gravitational wave sources, supernovae shock-breakouts, tidal disruption events around super massive blackholes, etc. The telescope was designed for covering the large error circle of GW detectors, FoV~100 deg2. Thanks to the high quantum efficiency of “delta-doping” detector, the detection limit achieves 20 mag (AB) for 1800 s exposure in NUV band, which is sufficient to detect UV emission from a binary neutron star merger within 200 Mpc from the earth. The satellite has a high-performance on-board computer for on-orbit analysis to detect transient sources and measure the magnitude and the accurate position of the target. The obtained information is required to be transferred to the ground within 30 min from the detection to start multi-messenger follow-up observations utilizing ground-based observatories and astronomical satellites. In this presentation we show the mission overview and conceptual design of the satellite system

Development of Attitude Sensor using Deep Learning

A new method for attitude determination utilizing color earth images taken with COTS visible light camera is presented. The traditional earth camera has been used for coarse attitude determination by detecting the edge of the earth, and therefore it can only provide coarse and 2-axis information. In contrast, our method recognizes the ground pattern with an accuracy of sub-degrees and can provide 3-axis attitude information by comparing the detected ground pattern and the global map. Moreover, this method has advantages in the size, mass and cost of the detector system which consists of a cheap optical color camera and a single board computer. To demonstrate the method in space, we have developed a sensor system named “Deep Learning Attitude Sensor (DLAS)”. DLAS uses COTS camera modules and single board computers to reduce the cost. The obtained images are promptly analyzed with a newly developed real-time image recognition algorithms

The Performance Test of pnCCD with FPGA-Based Operating System for a CubeSat Mission

On 17 August 2017, the LIGO/Virgo collaboration detected a signal of gravitational waves, named GW170817, associated with the merger of two neutron stars. This event was the first detection of the electromagnetic counterpart of gravitational wave events. In general, the error image region of the gravitational wave detectors ranges from a few square degrees to several hundred square degrees. To search for the origin of the gravitational waves or the energetic explosions such as the gamma-ray burst, X-ray observation covering a wide field of view with a good sensitivity is essential to achieve the goal. One of the good candidate instruments to achieve our goal is the combination of an X-ray optics called Lobster-eye optics (LEO) and a large area Si pixel imaging sensor. Furthermore, thanks to the light weight of LEO, it is possible to install on a small platform such as a CubeSat. Here, we introduce a future 3U CubeSat mission for searching the electromagnetic counterpart of gravitational waves in the soft X-ray band (0.4 ~ 10 keV) with ~arcmin localization accuracy. The pnCCD detector fabricated by PNSensor Inc. can achieve our mission requirements as an X-ray detector. To operate the pnCCD detector, we developed an FPGA-based fast readout system which is a very compact design to install on the CubeSat mission.Also, we investigate the readout noise of CAMEX, which is the readout ASIC of pnCCD. As a result, the readout noise was ~ 7.4 e-. In this paper, we report the performance of pnCCD applying our compact FPGA-based data processing system

Engineering Model Development of HIBARI: MicroSatellite for Technology Demonstration of Variable-Shape Attitude Control

We are developing a 40kg class microsatellite “HIBARI”. The main technical mission is demonstration a novel attitude control method called “Variable Shape Attitude Control (VSAC)” proposed by Matunaga, Tokyo Institute of Technology. This VSAC is based on an idea to utilize a reaction torque generated by changing the shape of satellites, for example driving solar array paddles by actuators. HIBARI is planned to be launched in fiscal year 2021 under “Innovative Satellite Technology Demonstration Program” led by JAXA. We are developing EM of HIBARI and describes those in this paper. Specifically, the results of missions, systems, and various tests are shown and the validity is derived

ARICA: Demonstration of a Real-time Gamma-Ray Bursts Alert System using the Commercial Satellite Networks

We demonstrate the real-time alert system of the transient astronomical sources such as cosmic gamma-ray bursts (GRBs) using two commercial satellite network devices. One is the Iridium’s Short Burst Data (SBD) and the other is the Globalstar’s STX-3. Although these satellite communication devices have been used in the space environment, it still needs to verify whether the network can be used as a GRB alert system. We are currently developing a 1U CubeSat called AGU Remote Innovative CubeSat Alert system (ARICA) which contains both SBD and STX-3 to demonstrate the real-time GRB alert system. The ARICA has been selected as the JAXA Innovative Satellite Technology Demonstration-2 and scheduled to be launched in the Japanese fiscal year 2021

Development and Initial On-orbit Performance of Multi-Functional Attitude Sensor using Image Recognition

This paper describes a multi-functional attitude sensor mounted on the “Innovative Satellite 1st” led by Japan Aerospace Exploration Agency which was launched in January 2019. In order to achieve the high accuracy determination in low cost, we developed a novel attitude sensor utilizing real-time image recognition technology, named “Deep Learning Attitude Sensor (DLAS)”. DLAS has two type of attitude sensors: Star Tracker(STT) and Earth Camera (ECAM). For the low-cost development, we adopted commercial off-the-shelf cameras. DLAS uses real-time image recognition technology and a new attitude determination algorithm. In this paper, we present the missions, methods and system configuration of DLAS and initial results of on-orbit experiment that was conducted after the middle of February 2019, and it is confirmed that attitude determinations using ECAM and STT are performed correctly

Flight Model Development of the AGU Remote Innovative CubeSat Alert System - ARICA

We present the flight model development of the 1U CubeSat, AGU Remote Innovative CubeSat Alert system (ARICA), which is scheduled to be launched in the Japanese fiscal year 2021 as the JAXA Innovative Satellite Technology Demonstration-2 project. The main goal of ARICA is to demonstrate the real-time alert system of the transient astronomical sources using commercial satellite network devices. The development of the flight components has been finished in April 2021. The thermal vacuum test was conducted at the end of April 2021. The vibration and shock tests were performed in May 2021. We are currently in the final stage of the development of ARICA to be ready for launch