Ten-Koh is a 23.5 kg, low-cost satellite developed to conduct space environment effects research in low-Earth orbit (LEO). Ten-Koh was developed primarily by students of the Kyushu Institute of Technology (Kyutech) and launched on 29 October 2018 on-board HII-A rocket F40, as a piggyback payload of JAXA’s Greenhouse gas Observing Satellite (GOSAT-2). The satellite carries a double Langmuir probe, CMOS-based particle detectors and a Liulin spectrometer as main payloads. This paper reviews the design of the mission, specifies the exact hardware used, and outlines the implementation and operation phases of the project. This work is intended as a reference that other aspiring satellite developers may use to increase their chances of success. Such a reference is expected to be particularly useful to other university teams, which will likely face the same challenges as the Ten-Koh team at Kyutech. Various on-orbit failures of the satellite are also discussed here in order to help avoid them in future small spacecraft. Applicability of small satellites to conduct space-weather research is also illustrated on the Ten-Koh example, which carried out simultaneous measurements with JAXA’s ARASE satellite.

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A small, deep-space probe, Shinen2, was developed under collaboration with the Kyushu Institute of Technology and Kagoshima University. The Shinen2 was launched by an H-2A rocket as a piggyback space probe with the JAXA's (Japan Aerospace Exploration Agency) asteroid probe, Hayabusa2, in 2014. The outer shape of the Shinen2 has a quasi-spherical diameter of 50 cm, and a mass of approximately 18 kg. An example of a deep-space probe to explore beyond the moon beyond has not been developed by any university, and no private companies exist. There are many technical aspects for the development of a small spacecraft to explore deep space. One is deep-space communication. The purpose of this development is to substantiate new deep-space communication methods used by amateur radio communications without the deep-space network of JAXA, NASA (National Aeronautics and Space Administration) or ESA (European Space Agency). The other subject is the realization of autonomous control of space probes. A communication control computer, a power control computer and a system control computer were equipped in Shinen2. The system control computer is called the Shinen2 control unit (SCU), and can control the total system of the Shinen2. Many satellites have been developed to orbit the earth. We have obtained a lot of experience, such as how computers are destroyed by radiation. There are no cases which explore deep space using a small spacecraft. The radiation measures are unknown for small satellites in deep space. This paper describes the methods of the total system control and measures radiation in deep space.

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On 29 October 2018 at 13:08 Japanese Standard Time was successfully launched the Greenhouse gas Observing SATellite (GOSAT-2) from the JAXA Tanegashima Space Center. Piggy-back with the GOSAT-2 satellite in a circular (623 km), polar synchronous orbit, was launched the 22 kilogram mass satellite Ten-Koh (http://kit-okuyama-lab.com/en/ten-koh/). It was developed in Kyushu Institute of Technology by Prof. K. Okuyama, Chief Scientist of the Spacecraft. Ten-Koh satellite is observing Low Earth Environment (LEO). The primary purpose is to provide valuable data for future development of satellites for operation. Ten-Koh's primary science instrument is the Charged Particle Detector (CPD) developed at the Prairie View A&M University, and NASA Johnson's Space Center of Houston, TX, USA. Principal Scientist of this payload is Prof. P. Saganti (https://www.pvamu.edu/raise/space-payload/charged-particle-detector-2018/). Principal Engineer of the CPD project is S. D. Holland (formerly with NASA-JSC and currently with Holland-Space LLC, Houston, TX, USA). SRTI-BAS received a request from Prof. Saganti to develop a Liulin type instrument to be part of the CPD payload. Scientists from SRTI's Solar-Terrestrial Physics Department have developed and handed three units per the request (engineering, flight, and operational models) of the instrument named ?Liulin Ten-Koh?. These instruments are similar to the RADOM instrument, which worked in 2008-2009 on the Indian Moon satellite Chadrayaan-1 [12]. This paper describes the flight model, ?Liulin Ten-Koh Saganti? instrument and the standard sources radiation tests, which were performed during the calibrations in the laboratory of SRTI-BAS. As of this writing, Ten-Koh spacecraft is making polar orbit passes as expected at about 623 km altitude and at 98 degree inclination with very healthy telemetry data as received by several ground stations across the world. The first received data from ?Liulin Ten-Koh Saganti? instrument of the Ten-Koh spacecraft are presented. The available at this moment Galactic Cosmic Rays (GCR) L-value profiles of the dose rate and the dose to flux ratio (D/F) from 11 December 2018 are compared with the R3DE profile at International Space Station (ISS). In addition, the integral ?Liulin Ten-Koh Saganti? instrument LET spectrum from 11 December 2018 is compared with spectra from other instruments, measured in and out of the Earth magnetosphere.