Space environment (natural and artificial) Realtime solar activity and space environment information for spacecraft operation

Transcription

1 ISO 2008 All rights reserved ISO TC 20/SC 14 N873 Date: ISO/CDV ISO TC 20/SC 14/WG 4 Secretariat: Space environment (natural and artificial) Realtime solar activity and space environment information for spacecraft operation Élément introductif Élément central Élément complémentaire Warning This document is not an ISO International Standard. It is distributed for review and comment. It is subject to change without notice and may not be referred to as an International Standard. Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to provide supporting documentation. Document type: International Standard Document subtype: Document stage: (20) Preparatory Document language: E N:\Publications\Standards\International Standards\SC14\Project Files\ISO 16709\CD\CDV\CDV16709.doc STD Version 2.1c2

2 Copyright notice This ISO document is a working draft or committee draft and is copyright-protected by ISO. While the reproduction of working drafts or committee drafts in any form for use by participants in the ISO standards development process is permitted without prior permission from ISO, neither this document nor any extract from it may be reproduced, stored or transmitted in any form for any other purpose without prior written permission from ISO. Requests for permission to reproduce this document for the purpose of selling it should be addressed as shown below or to ISO's member body in the country of the requester: [Indicate the full address, telephone number, fax number, telex number, and electronic mail address, as appropriate, of the Copyright Manger of the ISO member body responsible for the secretariat of the TC or SC within the framework of which the working document has been prepared.] Reproduction for sales purposes may be subject to royalty payments or a licensing agreement. Violators may be prosecuted. ii ISO 2008 All rights reserved

3 Contents Page 1 Scope Normative reference Terms and Definitions solar flare solar wind Coronal Mass Ejection (CME) Long Duration Event (LDE) F geomagnetic storm Planetary K index (Kp) Deep-Space Symbols and abbreviated terms Space environment data and information important for spacecraft operation Level and Trend of Solar Activity Solar flare and CME occurrence Solar X-ray Radiation Solar High Energy Particle K-index of geomagnetic field Solar wind plasma data High energy electrons at GEO Solar EUV proxy index... 4 ISO 2008 All rights reserved iii

4 Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. ISO was prepared by Technical Committee ISO/TC 20,, Subcommittee SC 14,. iv ISO 2008 All rights reserved

5 Introduction This standard describes real-time data and information on space environment and solar activity important for spacecraft routine operation. Recent progress of understanding space environment and its influence to spacecraft systems and subsystems tells us that space environment and its variation cause various kind of trouble of spacecraft. To reduce spacecraft trouble and its influence, knowledge of space environment, routine checking and understanding of current solar activity and space environment is very useful. Knowledge and understandings of real-time data and information give us also an important clue for initial analysis of spacecraft trouble. Critical operation such as launch, initial start-up and maneuvering should be planned and executed after checking and analysis of solar activity and space environment condition. This document describes real-time data and information on space environment as well as solar activity which should be monitored by operator of spacecraft. List and explanation of solar and space environment data and information are provided. The data described in this standard is provided by specific institute to public domain. Listing of data source is not a scope of this standard. Preparing URL listing and/or construction of www site including the data defined in this standard is recommended. ISO 2008 All rights reserved v

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7 WORKING DRAFT ISO/WD Realtime solar activity and space environment information for spacecraft operation 1 Scope This document describes real-time data and information on space environment as well as solar activity which should be checked by operator in spacecraft routine operation. Only data which can be easily accessed by non-expert of space physics and solar physics are included because this document is edited as a guideline for spacecraft operator on console. The data, model, and knowledge to be used only for spacecraft design and manufacturing are out of scope of the document. Concrete method and detail procedure of risk evaluation and avoidance should be prepared by each program with tailoring this standard. 2 Normative reference None 3 Terms and Definitions For the purposes of this document, the following terms and definitions apply 3.1 solar flare explosive solar surface phenomena observed as sudden brightening in x-ray and other electromagnetic radiation 3.2 solar wind continuous plasma stream ejected from upper solar atmosphere and expanding to the outer boundary of solar system 3.3 Coronal Mass Ejection (CME) explosive mass ejection from the sun leading solar wind and geo-space disturbance as well as radiation hazard. 3.4 Long Duration Event (LDE) solar flare which is enduring long-time. 3.5 F10.7 solar radio flux measured at wavelength of 10.7cm (f=2.8ghz) which is used as proxy for solar extreme ultraviolet (EUV) flux. 3.6 geomagnetic storm temporal disturbance of the Earth magnetic field mainly caused by solar wind disturbance and irregularity. ISO 2008 All rights reserved 1

8 3.7 Planetary K index (Kp) geomagnetic activity proxy index derived from data by a network of geomagnetic observatories. The Kp ranges in 28 steps from 0 (quiet) to 9 (disturbed) with intermediate values denoted by -, o, or +, resulting in 0o, 0+, 1-,1o, 1+, 2-, 2o, 2+,..., 8-, 8o, 8+, 9-, and Deep-Space space far from the earth which is outside of geomagnetic field influence. Accroding to ITU-R definition, space at distance from the Earth equal to or greater than 2*10^6 km. 4 Symbols and abbreviated terms AOCS Attitude & Orbit Control System EUV GEO LEO MEO MeV Extreme Ultra-Violet Geosynchronous Earth Orbit Low Earth Orbit Medium Earth Orbit Mega electron volt SAP: Solar Array Panel 5 Space environment data and information important for spacecraft operation 5.1 Level and Trend of Solar Activity Category: GEO/MEO/LEO/Deep-Space General description: Overview proxy of solar activity level based on synoptic observation. Influence and concern to spacecraft operation: Solar activity, including flares and CME, are the source of radiation hazard for space systems and cause of change of geo-space condition as space system environment. Level and trend of general solar activity is useful for general space environment risk evaluation. Method for measurement or production: Relative sunspot number, solar decimeter radio flux index (f10.7 radio index), Soft X-ray background available from public domain and reporting service. 5.2 Solar flare and CME occurrence Category: GEO/MEO/LEO/Deep-Space General description: Flare information and listing including time, location, scale and associated event information. Influence and concern to spacecraft operation: Solar flares and associating CME are major source of space environment disturbances. Generally, long duration and strong flares are thought to be important for risk evaluation on satellite operation. Method for measurement or production: Flare information and listing based on satellites and ground-base observation available from public domain and reporting service 2 ISO 2008 All rights reserved

9 5.3 Solar X-ray Radiation Category: GEO/MEO/LEO/Deep-Space General description: Total X-ray intensity radiated from the Sun. On the solar flare, the intensity increase rapidly. Long duration event (LDE) on X-ray plot are important because the LDE event sometimes drive disturbance harmful for space systems. Influence and concern to spacecraft operation: Solar X-ray radiation is the widely used indicator for solar activity level and flare and associating disturbance harmful for space systems. Method for measurement or production: Remote measurement by satellite sensor 5.4 Solar High Energy Particle Item Solar High Energy Particle Category: GEO/MEO/LEO/Deep-Space General description: Ions accelerated to high energy by solar flare and/or CME process including interplanetary disturbance. Influence and concern to spacecraft operation: Onboard computer malfunction due to upset of semiconductor devices, deterioration of SAP, electric devises, optical sensor etc Method for measurement or production: In-situ measurement by satellite sensor 5.5 K-index of geomagnetic field Category: GEO/MEO/LEO General description: Horizontal component geomagnetic field strength observed by ground based observation. Planetary K index (Kp) is convenient for satellite operators Influence and concern to spacecraft operation: Storm and sudden change of geomagnetic field is the cause of change of geo-space condition as a space system environment. Level and trend of Kp index is useful for general space environment risk evaluation. Method for measurement or production: Ground based magnetometer observation network and its real-time data circulation. 5.6 Solar wind plasma data Category: GEO/MEO/LEO/Deep-Space General description: Plasma and magnetic field property of interplanetary space. Geomagnetic storms are results of electro-magnetic interaction between solar wind magnetic field and geomagnetic field. Influence and concern to spacecraft operation: Precaution of geomagnetic disturbance caused by interplanetary shock. Sub-storms caused by high speed wind stream is potential cause of satellite malfunction. Increase of electron density may cause failure of electric component and harnesses including power or AOCS subsystem crucial for satellite survival. Method for measurement or production: In-situ measurement by satellite sensor ISO 2008 All rights reserved 3

10 5.7 High energy electrons at GEO Category: GEO/MEO General description: Near GEO, electron population is dominant comparing with proton. The electron flux change has a relation with geo-magnetic storm and sub-storm. Influence and concern to spacecraft operation: High energy (>MeV) electron is considered major driver of satellite charging and following discharging including component and harness inside spacecraft. The charging and discharging is one of the major cause of GEO satellite malfunction due to failure of electric component and harnesses including power or AOCS subsystem crucial for satellite survival.. Method for measurement or production: In-situ measurement by satellite sensor 5.8 Solar EUV proxy index Category: LEO General description: Atmospheric density change in LEO is caused by solar EUV radiation, which influences air drug to LEO satellite. Influence and concern to spacecraft operation: The proxy called f10.7 is used as solar EUV proxy parameter to deduce satellite drag on satellite orbital analysis. Abrupt increase of the proxy may cause severe trouble due to drastic change of satellite drag. Method for measurement or production: Ground based measurement by solar radio observatory. 4 ISO 2008 All rights reserved