Session
Technical Session X: The Year in Review
Abstract
HORYU-II is a 30cm-cubic nano-satellite weighing 7.1kg developed by Kyushu Institute of Technology. HORYU-II was launched to 680km Sun-synchronous orbit as a piggy-back satellite onboard a H-IIA rocket of JAXA on May 18, 2012 (Japan standard time). Its main mission is to demonstrate high voltage photovoltaic power generation technology. HORYU-II succeeded in generating high voltage photovoltaic power, up to 350V, which is the world record as power generation voltage in orbit. The past record was 160V held by the International Space Station. HORYU-II also carried out other technology demonstration missions related to electrostatic discharge mitigation solar array designs, a spacecraft charging monitor, a passive spacecraft charging mitigation device, and a debris impact sensor. Three weeks after the launch, HOYRU-II suffered a serious anomaly for one month, and the satellite was not able to communicate with the ground station. Based on the anomaly investigation including various ground tests, the authors judged that a single event latch-up (SEL) due to radiation was the most probable cause. SEL occurred on two microprocessors. When the second SEL occurred, the battery was depleted due to the increased current consumption. The battery’s depletion reset HORYU-II, and the satellite could be restored to its original condition. The lessons of HORYU-II suggest the needs of environmental testing standard to improve the satellite reliability, especially at the early phase of operation in orbit.
Presentation Slides
Mission Results and Anomaly Investigation of HORYU-II
HORYU-II is a 30cm-cubic nano-satellite weighing 7.1kg developed by Kyushu Institute of Technology. HORYU-II was launched to 680km Sun-synchronous orbit as a piggy-back satellite onboard a H-IIA rocket of JAXA on May 18, 2012 (Japan standard time). Its main mission is to demonstrate high voltage photovoltaic power generation technology. HORYU-II succeeded in generating high voltage photovoltaic power, up to 350V, which is the world record as power generation voltage in orbit. The past record was 160V held by the International Space Station. HORYU-II also carried out other technology demonstration missions related to electrostatic discharge mitigation solar array designs, a spacecraft charging monitor, a passive spacecraft charging mitigation device, and a debris impact sensor. Three weeks after the launch, HOYRU-II suffered a serious anomaly for one month, and the satellite was not able to communicate with the ground station. Based on the anomaly investigation including various ground tests, the authors judged that a single event latch-up (SEL) due to radiation was the most probable cause. SEL occurred on two microprocessors. When the second SEL occurred, the battery was depleted due to the increased current consumption. The battery’s depletion reset HORYU-II, and the satellite could be restored to its original condition. The lessons of HORYU-II suggest the needs of environmental testing standard to improve the satellite reliability, especially at the early phase of operation in orbit.
