I-SWEAT Micro-Satellite Mission: Ionospheric Space Weather Effects in Auroral Thermosphere

Andrew Yau 游荣森 , D.D. Wallis University of Calgary 加拿大卡尔加里大学Yunlong Lin 林云龙 , J. McConnell, M. Shepherd, B. SolheimYork University 加拿大约克大学P. Harrison1, R.B. Langley2 ， W. Lunscher3, J.M. Noel4

1Magellan Bristol 2UNB 3COM DEV 4RMC

Supported by Canadian Space Agency 加拿大宇航局

电离层及热层空间天气研究微小卫星： I-SWEAT

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Outline 报告内容• Focus of talk: Science 报告焦点 : 科学• Scientific Motivation 科学动机 • Scientific Objective 科学目标• Mission Concept 科学任务的概念研究

– Results from Mission Concept Study 初步结果和结论我的国语不太行 , 用英语作这个报告 , 希望各位多多原谅 … …

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Scientific Motivation 科学动机 (1)

● Understand physics of ionosphere-thermosphere response to space weather: magnetic storms and substorms

研究空间天气 ( 磁暴和亚暴 ) 对电离层以及热层的影响 ● Advance prediction capability of space weather effects

改进有关空间天气影响电离层以及热层的预测 , 预报 , 监测和预警 Ionosphere: Total Electron Content (TEC) increase at mid/high latitude 电离层：在中，高纬区域“电子浓度总含量”的增长 Scintillation: disrupt radio communications and GPS navigation 对无线电信号闪烁的影响： 扰乱无线电通讯和 GPS 导航Thermosphere: Heating, density increase, expansion at high latitude 热层： 加热过程，密度增长，在高纬的扩张Anomalous orbit drag to low-Earth-orbit (LEO) satellites 对低地球轨道卫星轨道保持的影响：产生不规则轨道拖曳

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Space Weather Effects in Ionosphere磁暴期间电子浓度总含量 (TEC) 增加及 GPS 信号闪烁TEC increase and GPS signal scintillation in magnetic storm

Storm electron density (SED) increase over North America in Oct. 2003 “super-storm” [Foster 2005] 2003 年 10 月北美地区磁暴期间电子密度增长

GPS scintillation at Ithaca, NY, in minor magnetic storm [Kintner 2007]

2001 年 9 月小磁暴期间同样也有GPS 信号闪烁

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Scientific Motivation 科学动机 (2)

● Understand physics of ionosphere-thermosphere response to space weather: magnetic storms and substorms

研究空间天气 ( 磁暴和亚暴 ) 对电离层以及热层的影响 ● Advance prediction capability of space weather effects

改进有关空间天气影响电离层以及热层的预测 , 预报 , 监测和预警 Ionosphere: Total Electron Content (TEC) increase at mid/high latitude 电离层：在中，高纬区域“电子浓度总含量”的增长 Scintillation: disrupt radio communications and GPS navigation 对无线电信号闪烁的影响： 扰乱无线电通讯和 GPS 导航Thermosphere: Heating, density increase, expansion at high latitude 热层： 加热过程，密度增长，在高纬的扩张Anomalous orbit drag to low-Earth-orbit (LEO) satellites 对低地球轨道卫星轨道保持的影响：产生不正常轨道拖曳下降

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Space Weather Effects in Thermosphere 磁暴期间高层大气扩张 ,

导致低地球轨道卫星不正常轨道下降Atmospheric expansion & anomalous orbit drag in magnetic storm

Anomalous drag of CHAMP orbit by ~500 m (ΔSMA) in Oct. 2003 storm at 410 km altitude2003 年 10 月的磁暴对 410 公里高度的CHAMP 卫星产生 500 米的轨道下降

>2 increase in atmospheric mass density at 410 km inferred on CHAMP [Sutton 2005]2003 年超过 2 倍的大气密度增长对 410 公里高度的 CHAMP 卫星的影响

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Space Weather & Anomalous Orbit Drag 空间天气对人造卫星轨道的影响

• Spacecraft collision avoidance:– Effective avoidance strategy requires

orbit prediction to within ~3-5 km• “State-of-the-art” orbit prediction:

– Ap and F10.7 based (e.g. STK) – Has large uncertainty: up to ~20 km

• Orbit Error Simulation/Analysis: • Storm/substorm related anomalous orbit drag

contributes significantly to errors in orbit prediction. 避免卫星在轨碰撞； 提高轨道预报能力； 轨道预报偏差的模拟和分析； 磁暴和亚暴对低地球轨道卫星的轨道预报的正确性具有重要影响

February 11, 2009

U.S. And Russian Satellites Collide

“Two communications satellites — one Russian, one American — cracked up in silent destruction… The American satellite was an Iridium, …” 纽约时报（ 2009 年 2 月 11 日）对美苏卫星相撞的报道：美国卫星是提供卫星电话服务的铱星

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Scientific Objective 科学目标Space weather effects in ionosphere-thermosphere

Thermosphere Expansion热层扩张

Ionosphere enhancement /

Depletion电离层变化Ionospheric

Currents电离层电流Atmosphericcompositionand velocity高层大气成分和速度

TEC aboveand below S/C卫星上面和下面的电子密度

Field-aligned currents from ΔB电流在磁场中的分布

Satellite orbit drag轨道下降

S/C position, velocity,

acceleration

Dual frequency GPS receiver双波段 GPS

Dual frequencyGPS receiver双波段 GPS

Magnetometer磁强计Neutral analyzer中性粒子分析器

Scientific Objective 科学目标 Measurements探测需求 Instruments测仪器Investigation Objectives

研究目标

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Mission Concept 卫星计划和概念

Micro-satellite: • 3 instruments on

“QuickSat” BusOrbit:• Polar LEO: 300-700 km• Sun- or non-Sun-syncScience operations: • Operation in selected

orbits / orbit segments

卫星 : “ 快捷”微小卫星仪器 : 中性粒子质量及速度分析器 , 双频 GPS 接收机 , 磁强计轨道 : 高倾角轨道，或者极轨；高度 : 300-700 公里

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System Architecture 卫星系统和空间任构成I-SWEAT Spacecraft

QuickSat Bus Payloads

ANA

DGR

FMG

MOC Ground StationCSA-St Hubert

SOC Ground StationUniversity of Calgary

Additonal Ground Station(s)TBC

High-Speed Ethernet

High-Speed Ethernet

Communications

UHF DownlinkVHF Uplink

Power

ADCS

C&DH

ActuatorsWheel (1)

Torque Rods (3)

SensorsCSS (12), MSS (2)Earth Sensors (2)Magnetometer (1)

ACSCPU

C&DHCPU

Han

dove

r

DataStorage

RSS 422RSS 422

RSS 422

Cmd

TMTransmitters

(2)Receivers

(2) TM

Uplinked Commands

Solar Array

Battery

MBPC

Onboard data

Onboard power

RF Uplink

RF Downlink

Instrument Payload:

ANA: Atmospheric Neutral AnalyzerDGR: Dual-frequency GPS ReceiverFMG: Fluxgate Magnetometer

中性粒子质量及速度分析器 双频 GPS 接收机 磁强计

Ground System:

Amateur-radio type ground station

Mission Operations Center

Multi Science Operation Center (SOC)

多元化分布式地面站

Uplink/downlink: VHF/UHFVHF/UHF 通讯

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I-SWEAT QuickSat Spacecraft 加拿大“快捷”微小卫星平台

FMG deployedon boom磁强计

DGR side-facing antenna双频 GPS 接收机

VHF Uplink Antenna

X (ram)

Z (nadir)

ANA ram-facing entrance slit中性粒分析仪 Solar panels

deployment

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Atmospheric Neutral Analyzer (ANA) 中性粒子质量及速度分析仪探测原理

1. Entrance aperture accepts neutrals; deflects ions

2. Electron beam ionizes a fraction of neutral; retains incident velocity

3. Accelerate ions to same perpendicular energy/charge

6. CCD images ion positions (hence neutral velocities)

5. Accept only resonant ions

4. RF Analyzer energizes ions of “resonant” velocity (M/q)

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Dual-Frequency GPS Receiver (DGR) 双频 GPS 接收机设计

• Heritage– Simplified version of e-POP GAP

– GAP co-developed by UNB and Magellan Bristol

– GAP has array of 5 GPS receivers networked to 4 patch antennas and 1 occultation antenna

• Design– 2 GPS receivers networked to 2 antennas

– Re-use GAP interface, power, GPS cards

– Modified GAP implementationCASSIOPE/e-POP GAP electronics

CASSIOPE/e-POP GAP electronics

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Fluxgate Magnetometer (FMG) 磁通门磁强计的设计

• Measurement Goal: field-aligned currents >1 A/m2 along >1 km path– Sampling: 32 samples/sec ~500 m/sample; resolution: 1 nT

• Fluxgate magnetometer: measures magnetic field vector components by modulating permeability of ferro-magnetic rings inside detection coils– Non-zero magnetic flux inside coils induces voltage at 2 modulation freq.

– Low-freq. feedback current through coil

ambient magnetic flux component

• Design: – Based on CASSIOPE/e-POP Magnetic

Field Instrument (MGF)

– Resolution: 1/16 nT; Range: 65,536 nT

CASSIOPE/e-POP MGF sensor assembly

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I-SWEAT Summary 初步研究结果和结论• Mission Concept:

QuickSat bus in low-Earth polar orbit

Instruments: Atmospheric Neutral Analyzer, Dual-frequency GPS Receivers, Fluxgate Magnetometer

Low-cost science operations; multiple ground stations

• Scientific Objective:

Study space weather effects in ionosphere-thermosphere

TEC enhancement; Thermosphere expansion; anomalous orbit drag

经过二年的初步论证和概念设计，我们提出利用加拿大的“快捷”微小卫星平台在高倾角低地球轨道（轨道高度 : 300-700 公里）上对电离层及热层的中性粒子，磁场和电子密度总含量进行探测，确切掌握空间天气在磁暴和亚暴期间的变化对电离层和热层的影响，进而深入了解其对卫星的影响。 这些影响至少包括：电子密度总含量增长， GPS 信号闪烁，热层扩张和异常轨道下降。进一步改进空间天气影响电离层及热成层的预测和预报方法将直接有利于卫星轨道设计和轨道操作。

这颗电离层及热层空间天气研究微小卫星（ I-SWEAT ）将至少携带 3 种探测仪器（中性粒子质量速度分析仪 , 双频 GPS 接收机 , 磁强计），利用多元化分布式地面站独立完成低成本、高效率的长期科学探测任务。与其他空间天气研究卫星同步进行集群式组网探测，将进一步深化我们对空间天气物理过程的理解，扩大 I-SWEAT 对空间天气研究的意义。

卡尔加里大学和约克大学将汇同其他加拿大大学和研究部门进行科学载荷和卫星平台的研制，我们欢迎各种形式的合作研究和联合探测。