Space Weather Effects and Applications

Eamonn Daly

ESA Space Environments and Effects Section

ESTEC

NoordwijkThe Netherlands

eamonn.daly@esa.int

Outline

• Defintions

• Review Effects (roughly divided between):– Effects on space systems– Effects on communications

and terrestrial effects

• User requirements

• Services

• Conclusions

What is “Space Weather”?

conditions on the sun and in the solar wind, magnetosphere, ionosphere, and thermosphere

that can influence the performance and reliability of space-borne and ground-based technological systems and can endanger human life or health

[US National Space Weather Programme]

Affected by LocalSpace Environment

Affected by LocalSpace Environment

User Sectors

Affected byIonospheric Disturbances

Affected byIonospheric Disturbances

Air Transport ServicesAir Transport Services

Affected byGeomag. Induced Currents

Affected byGeomag. Induced Currents

Spacecraft Operations ServicesSpacecraft Operations Services

Launcher SupportLauncher Support

Human Spaceflight SupportHuman Spaceflight Support

Science Missions Operations ServicesScience Missions Operations Services

Navigation ServicesNavigation Services

Communications ServicesCommunications Services

Power Industry ServicesPower Industry Services

Survey, Oil & Gas ServicesSurvey, Oil & Gas Services

Spacecraft DevelopmentSpacecraft Development

OthersOthers

TourismTourism

Air Transport ServicesAir Transport Services

Other SSA ServicesOther SSA Services

Effects

Space Weather Effects result from complex interactions between the environment and the affected systems:– Satellites affected by radiation, plasma, atmosphere,

particulates;– Radiation hazards to astronauts on ISS, future exploration

missions;– Radiation hazards to crew and avionics on aircraft;– Disruption to communications relying on the ionosphere;– Disruption of navigation satellite signals (GPS - Galileo);– Ground power outages from currents induced in lines;– Others (Geological Surveys, Climate, Tourism,…);

see www.esa.int/spaceweather

Surface degradation from radiation

Solar array arc discharge

Electromagnetic pulse from vehicle discharge

Single event effects in microelectronics:bit flips, fatal latch-ups

Spacecraft components become radioactive

False stars in star tracker CCDs

1101 0101

Effects on Spacecraft

Solar array power decrease due to radiation damage

before after

Outside inner belt

Inside inner belt

Electronics degrade due to total radiation dose

Induced Voltage

Time

Courtesy G. Ginet, AFRL

Spacecraft Effects

Radiation Effects are caused by:• Total integrated ionising or non-ionising dose

(energy absorbed/unit mass)– a problem for electronics, solar cells, materials, man

• Single event effects, including single event upset (non-permanent error in a bit), single event transients; latch-up (destructive); detector interference;– a problem for electronics, detectors and man

Plasma Effects due to:• Electrostatic charging causing electrostatic discharge →EM pulses;

– a problem for electronics• Plasma interactions with “exposed active” systems

– solar panel interconnects; electric propulsion; payloads; tethersNeutrals Cause:• Drag, depending on atmospheric density• Erosion of surfaces – the residual Oxygen is non-molecular and

corrosive• Contamination

Radiation in space

• The principal particles:– ProtonsProtons 0.1-300MeV

{radiation belts, solar particle events, cosmic rays}– IonsIons 0.1-300MeV

{cosmic rays, solar particle events, (radiation belts)}– ElectronsElectrons 0.01 - 10MeV

{radiation belts, (other planets) ((solar))}

• The main interaction mechanism is ionisation but other processes can be important

“Single-event” effects (SEE’s)

• a particle crosses (“hits”) a (small) sensitive target• the energy deposited causes a noticeable effect:

– ionisation free charge causes a bit to “flip”

– pixels of a CCD are “lit up” by creation of free charge

– DNA is damaged

• SEEs are becoming extremely difficult to evaluate in complex modern chips

SEUs on UoSAT-3 microsatellite memory SEUs on UoSAT-3 microsatellite memory

Mapped

Oct ‘89

Time behaviour

SEUs are from:• Cosmic rays and solar ions at high latitude• Radiation belt proton nuclear reactions in south Atlantic

An Aside: The South Atlantic Anomaly

• Earth’s magnetic field is an offset tilted and distorted dipole

• This brings the radiation belt down in the South Atlantic

500km

Radiation Effects on SOHO

Solar arraydegradation

Errors in on-board memory

Cosmic raybackgroundvaries withsolar cycle

SOHO Image “snowing” on 14 July 2000

ISO Star Tracker

• Error rate increases in small solar event

• provided software can cope, this phenomenon should not lead to problems

• but there are several cases of attitude stabilisation loss

XMM: Radiation Damage to Detectors

Orbit48-hr Highly eccentric

Apogee: 115000Perigee: 7000km

Inclination: 40o

Leads to potential degradation of CCDs and to background from

soft protons entering the mirror shells

Detectors (5 arrays)

Spectrometergratings

mirrors

Manned Missions Away from LEO Risk High Doses (prompt radiation sickness at ~100 REM (1 Sv); death at 400)

Ap

ollo

16

Ap

ollo

17

104 REM skin dose

103

What is done to avoid radiation problems?

• “radiation hardness assurance” in design process – Conservatism; design against worst cases

• Space weather effects on operations designed in to operations procedures if necessary

Spacecraft Interactions with Local Plasma Environment

• Hot plasma causes electrostatic charging of outer surfaces– Potential differences can lead to discharges

→ spacecraft failure (rare) or “anomalies”

• Also caused by energetic electrons getting inside materials and stopping– High electric fields lead to breakdown

discharges

Spacecraft-Plasma Interactions

Main engineering issue is high-level electrostatic charging• 27 February 1982: interruption (ESR)

on Marecs-A Maritime Com. Sat.

• Main anomaly & other small ones coincident with geomagnetic “substorms”

• Anomalies caused by electrostatic charging -> discharge– large areas of dielectric thermal blankets – large differential charging

• Marecs-A and ECS-1 satellites had power losseson sections of solar arrays

• Telstar 401 failure on 10th Jan 1997 following storm on 7th

• ANIK-E1 & E2 failures in 1994 and 1996

• Many other examples…

“Surface charging” is result of currents to a surface

• High level (negative) charging occurs because “hot” electrons dominate

• Often only possible in shadow

• Depends strongly on material

“Internal” electrostatic charging

• Meteosat 3 (1988-1992) had many disturbances• On average, environment was seen to get

severe before an anomaly

ThermalBlanket

Cables

Components

InsulatorsDischarge

PrintedCircuitBoards

MeV electrons penetrate material and build up an electrostatic charge

Anomalies on the morning side during storms

MeteosatMeteosat AnomaliesStatistical Survey (Rodgers et al.) of Meteosat-3 anomalies and their local time distribution

MP

GEO

Charging-Induced Anomalies

Hotplasma

0

6

Failure of Equator-S Spacecraft due to “killer electrons”

December 97

Primary CPU Fails

April 98

Back-up CPU Fails

Enhanced Hot Electrons

Canadian experiences (800 events over 25 years, courtesy Telesat Canada*)

Anik-E momentum wheel electronics provide an excellent example of an unambiguous space-weather-related failure **.

Conversely, the investigation of the March 1996 Anik-E1 power failure showed that, although initially suspected of being so, it was in fact not related to space weather.

** Evans, J. and Gubby, E. R., “Ground Loop Attitude Control System for the Anik-E Satellites” International Union of Radio Science XXVIth Assembly, University of Toronto 16 August 1999

Anik-A’s• 11 uncommanded mode switches of telemetry encoders.Anik-B• One earth sensor mode switch, believed to be caused by

optical solar reflector discharge.Anik-C’s• C1 and C2 had only a few phantom commands (i.e. mode

changes, unit turn-on/off);• C3 had more than 100 such events.Anik-D’s• D1 had only 3 events (uncommanded mode switches);• D2 suffered a major service outage on 8 March 1985,

when multiple events occurred simultaneously.Anik-E’s• Many phantom commands, especially RF amplifiers;• On 20 Jan 1994 both momentum wheel electronic units

failed on E2, one failed on E1;• Several RF amplifier failures.MSat• Many phantom commands;• Very large number of RF amplifier failures.Nimiq• A few phantom commands (as of Oct 1999)

* SPACE ENVIRONMENT EFFECTS AND SATELLITE DESIGN, Robin Gubby & John Evans, JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, 1999

Communications/ navigation effects

• RF signals through ionosphere experience phase errors due to plasma effect on EM propagation

• Signal delays lead to GPS navigation errors- a large sector of space weather services

Geomagnetically Induced Current Effects

• Strong ionsopheric currents induce geoelectric fields on the Earth’s surface (Faraday’s law of induction)

• Fields can cause currents to flow in power lines - transformer damage, network “tripping”and induce potential differences between pipelines and the ground, accelerating corrosion

• Magnetic field perturbations on Earth’s surface disrupt geological surveying that relies on magnetic/electric field sensing

Peak Neutron Flux at 10 km

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

0 0.5 1 1.5 2 2.5 3 3.5

Rigidity Cut-Off (GV)

Pe

ak

Ne

utr

on

Flu

en

ce

(n

/cm

2/s

ec

)

CR

23-Feb-56

29-Sep-89

19-Oct-89

Radiation Enhancements in the Atmosphere -Altitude & latitude variations

• Courtesy Clive Dyer (see IEEE TNS Dec. 2001 paper)

Neutron Fluence at 10 km

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

0 0.5 1 1.5 2 2.5 3 3.5

Rigidity Cut-Off (GV)

Ne

utr

on

Flu

en

ce

(n

/cm2)

CR(1 week)

23-Feb-56

29-Sep-89

19-Oct-89

Peak Neutron Fluxes at Different Altitudes,

1GV cut-off

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

0 5 10 15 20 25

Altitudes (km)

Ne

utr

on

Flu

x (n

/cm

2/s

) CR

23-Feb-56

29-Sep-89

19-Oct-89

Space Weather Services

• Provision of information (data, tailored information, warnings) driven by user requirements.

• Most established is US NOAA SWPC

• Many services in Europe addressing various “market sectors”

ESA’s Space Weather Applications Pilot Project

• Aim to support investigation of maturity of the “market”

• ~30 CO-FUNDED services established;

esa-spaceweather.netesa-spaceweather.net

Example Service: Human Spaceflight

Radiation Warning for ISS

Operations

• Manned example already well established:NASA-JSC system uses NOAA resources

• Science mission instrument shut-offe.g. ESA’s XMM and Integral take action if hazardous conditions are detected

• Launch authorities can delay launches(e.g. rapid decision taken for Cluster-II launch on July 16 ‘00)

• Reliability of forecast is a major obstacle

NASA ACE

NOAA GOES

Ground Based Magnetometers

NASA/POLAR

Some Examples of Current Resources

ESA/NASA SOHO

0.1

1

10

100

1000

10000

184.35 184.4 184.45 184.5 184.55 184.6

mep0e1

mep0e2

mep0e3

Event

0.1

1

10

100

1000

10000

184.35 184.4 184.45 184.5 184.55 184.6

mep0e1

mep0e2

mep0e3

EventNOAA/SEM

L1

ESA-EU GioveAurora

GNSS Scintillation Network (CLS)

Ionospheric monitoring (GPS TEC)

(CLRC-RAL, Space Weather System Studies 2000)

Applications needs differ from Science data needs

• Data type• Coverage• Timeliness• Continuity• Quality

• But science data remain a crucial resource for applications in the short-medium term

Requirements Analyses have been made since ESA system studies

SSA SW Services Addressing User Needs

– MonitorMonitor• the Sunthe Sun• solar windsolar wind• radiation beltsradiation belts• magnetospheremagnetosphere• ionosphereionosphere• surface B fieldsurface B field

– ProvideProvide• reliable local spacecraft (/launcher) radiation, plasma & electromagnetic data reliable local spacecraft (/launcher) radiation, plasma & electromagnetic data

for re-construction, nowcast & forecast of hazardous conditionsfor re-construction, nowcast & forecast of hazardous conditions• timely and reliable ionospheric disturbances nowcast and forecast timely and reliable ionospheric disturbances nowcast and forecast

important to Galileo signal and service qualityimportant to Galileo signal and service quality • thermospheric density for spacecraft drag calculationthermospheric density for spacecraft drag calculation• timely and reliable ionospheric density profile nowcast and forecasttimely and reliable ionospheric density profile nowcast and forecast• results of ground-level magnetic field variations monitoring and forecastresults of ground-level magnetic field variations monitoring and forecast

* nowcast = re-constructing in real-time the present environment * nowcast = re-constructing in real-time the present environment based on data, proxies & modelsbased on data, proxies & models..

Requirements Analyses: See poster of Glover et al.

Conclusions

• Space weather effects are increasing;

• Interactions that lead to effects can be very complex – requires considerable effort to analyse and mitigate;

• Services and affected users may need information of different types to science users;

• Development of coordinated space weather services in Europe is foreseen within “SSA”;

• (Note: ESA young graduate trainee, research fellowship and PhD partnering programmes)