Description of the "Liulin Ten-Koh" charged particles spectrometer for the Japanese "Ten-Koh" satellite

Abstract

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.