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Single-event upset (SEU) hardness varies across dies, wafers, and lots—even just after fabrication and further across time. Mechanisms of postfabrication variations include total ionizing dose (TID) effects, which are caused by long-term radiation exposure. This synergistic effect of TID on SEU hardness is a particular concern in integrated circuits used in space and nuclear radiation environments. This article shows that an electrical parameter called the data-retention voltage is useful in dealing with such TID effects on the SEU hardness of static random access memories (SRAMs), which are known to be particularly radiation-sensitive. Experiments showed that TID-induced variations in SRAM SEU hardness, i.e., variations in SEU cross sections, were predicted by measuring the data-retention voltage. In addition, these variations were canceled out by adjusting the power supply voltage according to its interesting relationship to the data-retention voltage. Results suggest that it might be possible in flight to predict and cancel out SEU hardness variations caused by TID and other synergistic effects.

著者人数: 14名, Accepted: 2019-11-26, 資料番号: SA1190197000

著者人数: 13名, Accepted: 2018-11-13, 資料番号: SA1180337000

Static random access memory (SRAM) is one the most sensitive devices to radiation. It may often exhibit undesired reversals of memory bits, called single-event upsets or soft errors. Sensitivity to such undesired events is widely quantified with the parameter of cross sections, which varies from cell to cell due to process variations. Many efforts have been made to quantify such variations, most commonly using simulations that often become a hurdle especially for commercial-off-the-shelf SRAMs. In this regard, an analysis method is proposed to extract such variations easily from radiation test data. It relies on the data retention voltage, which is an electrical parameter associated with the static noise margin. This voltage can be measured on a desk without special circuits. The validity of the proposed method is experimentally demonstrated using SRAM fabricated in a 65-nm silicon-on-insulator technology, which was exposed to various high-energy heavy ions simulating the effects of galactic and terrestrial cosmic rays. Theoretical discussion provides further evidence, while revealing an interesting relationship between the data retention voltage and power supply voltage. This relationship suggests power-supply voltage tuning to deal with chip-to-chip variations in cross sections and also with similar variations caused by total-dose effects and aging effects such as negative bias temperature instability.

第20回宇宙科学シンポジウム (2020年1月8日-9日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, 20th Space Science Symposium (January 8-9, 2020. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan, 資料番号: SA6000152020, レポート番号: S5-004

第6回スペースデブリワークショップ (2014年12月17日-19日. 宇宙航空研究開発機構調布航空宇宙センター(JAXA)(CAC)), 調布市, 東京, 6th Space Debris Workshop (December 17-19, 2014. Chofu Aerospace Center, Japan Aerospace Exploration Agency (JAXA)(CAC)), Chofu, Tokyo, Japan, HTV6号機への搭載を目指して、JAXAでは導電性テザー（EDT）実証実験「KITE」の開発を進めている。EDTは、導電性のワイヤー（テザー）に流れる電流と地磁気との干渉によって生じる電磁気力を利用する推進剤不要の推進系であり、システムの小型軽量化が可能な点に加え、マヌーバ中の推力方向制御が不要であることやデブリへの固定の容易性などの点で、低軌道デブリのデオービット用推進系として有力である。KITEでは700m級のテザーによるEDT技術の実証を予定しており、EDTを使用したデブリ除去システム構築のための最初のステップとなる。, An on-orbit demonstration of electrodynamic tether (EDT) on H-II Transfer Vehicle (HTV) is planned in JAXA. This plan is called KITE, Konotori Integrated Tether Experiment. The KITE is the first step to develop active space-debris removal systems using EDT. EDT is a promising as the de-orbit propulsion of the debris removal systems on low-earth orbits because of its various advantages, such as no consumable and low electric power required, no thrust vectoring needed during the maneuver, and easy attachment to debris. The primary objective of the KITE is to demonstrate the key technologies of EDT for debris removal., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1530025017, レポート番号: JAXA-SP-14-013

第32回エネルギーシンポジウム (2013年3月1日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県, The Space Energy Symposium (March 1, 2013. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, H-II Transfer Vehicle (HTV) is an unmanned cargo transfer vehicle to the International Space Station (ISS) developed and built by JAXA. HTV delivers supplies to the ISS and planned to be launched seven in total. To approach the manned base ISS safely, HTV have to keep power distribution to its system even if at the worst situation. A common design approach for Electrical Power System (EPS) in past unmanned spacecraft was the Design for Minimum Risk such that the highly reliable single electrical bus provides power to the system. However, the single bus can mitigate the risk of the loss of bus but the possibility of the loss of bus can not be denied. HTV EPS promoted Failure Tolerant Design and achieved the ISS common requirement of Two Failure Tolerant for Safe. HTV EPS applied redundancy to the bus system and placed circuits around bus system not to propagate failures especially short circuits. HTV EPS consists of 120 V system and 50 V system. 50 V system maintains HTV function such as Guidance, Navigation and Control (GNC) system, Data Handling (DH) system, and Communication (COM) system. 120 V system received power from the ISS during the attached phase and provides power to the pressurized section of the HTV where the ISS crew can enter. 120 V system also convert power to 50 V system and keep HTV function during the attached phase. This paper gives an outline of HTV 50 V system, its characteristics, power control design and its operation and on-orbit data compared with simulation on ground. HTV is an transportation vehicle so that its recurring cost is one of the most important parameter in procurement. As an HTV improvement activity, authors evaluated HTV EPS design comparing on-orbit operation result with simulation on ground from the aspect of power balance between provision and consumption and had a success of optimization of amount of solar array in subsequent HTVs., 形態: カラー図版あり, 形態: PDF, Physical characteristics: Original contains color illustrations, Physical characteristics: PDF, 資料番号: AA0061912005, レポート番号: SES-2012-005

第35回宇宙エネルギーシンポジウム (2016年3月3日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県, 35th ISAS Space Energy Symposium (March 5, 2016. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 資料番号: SA6000052009

第58回宇宙科学技術連合講演会（2014年11月12日-14日. 長崎ブリックホール), 長崎市, 長崎県, "Japan Aerospace Exploration Agency has developed Atotie-mini module for HTV4 to measure the potential of HTV against ambient plasma. For HTV5, JAXA developes the Konotori Advanced SPace Environment Research equipment module (KASPER module), which is based on Atotie-mini module, to measure the potential of HTV and plasma current around HTV. KASPER module also has debris sensors for demonstration test.In addition, JAXA plans to perform demonstration experiment for electrycal dynamic tether (EDT) in HTV. In this experiment, it is necessary to measure the potential of HTV when HTV deploys EDT, because the pontential of HTV changes due to EDT. For the demonstration experiment, we developes LP-POM module to measure the pontential of HTV and plasma current. In this report, we report the overview, current situation and experiment plan of KASPER module and LP-POM module.", 資料番号: AC1500073000, レポート番号: JSASS-2014-4437

第33回宇宙エネルギーシンポジウム (2014年2月14日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県, 33rd ISAS Space Energy Symposium (February 14, 2014. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 資料番号: SA6000022009

第13回宇宙科学シンポジウム (2013年1月8日-9日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, 13th Space Science Symposium (January 8-9, 2013. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan, 資料番号: SA6000063151, レポート番号: P2-124

A ceramics sound absorption material made of a ceramics block which is obtained by adding a combustible pore-forming material to at least one selected from refractory clay and refractory chamotte and calcining the blend, which has communicating pores having a main pore diameter of 0.2 to 2,000 μm, which has an air permeability of at least 1 cm3·cm/cm2·sec·cmH2O, and in which surface a large number of sound absorption holes or sound absorption grooves are formed, a glaze being applied to only the surface except the inner peripheral surfaces and the bottom surfaces of the sound absorption holes or the sound absorption grooves to form a glaze layer which fills the communicating pores and which is substantially free from an air permeability. The porous ceramics sound absorption material is excellent in sound absorption characteristics and a weatherability, and is less stained in particular. Stains once adhered are easily removed, and a good appearance can be maintained for a long period of time.