Space Radiation Effects on Aircraft

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Space Radiation Effects on Aircraft
European Space Weather Week ESWW-II 17 November
2005
Captain Bryn Jones SolarMetrics Limited
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Overview

• Space Radiation Environment
• Recent Storm Impacts
• Next Generation Air Space Transportation
• Integrating Space Weather into Operations
• Summary

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Space Radiation Environment
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Space Radiation Environment - Events

• Galactic Cosmic Rays (GCRs)
• Constant background
• Modulated by Space Weather (11-year solar cycle,
  Coronal Mass Ejections (Forbush Decrease) etc.)

• GCRs at Earth
• Shielded by Earths magnetic field
• High dose at high latitudes, low dose at low
  latitudes
• Variation by a factor of 2

• Atmosphere provides a further barrier
• Cascade of secondary particles reaches Max Dose
  Rate at 60,000 ft
• From 10,000 to 60,000 ft, dose rates double every
  10,000 ft

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Space Radiation Environment - Events
Solar Cycle

• Cyclic activity 27-day, 11-year, 22-year,
  88-year.
• Solar Cycle causes cosmic radiation dose rates to
  vary by a factor of 2
• High doses during Solar Min., Low doses during
  Solar Max.

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Space Radiation Environment - Events

• Coronal Mass Ejection (CME)
• Massive explosion on the surface of the Sun that
  ejects plasma into space
• Causes
• Forbush Decrease (a decrease in the background
  cosmic radiation dose)
• warning time hours to days
• Solar Cosmic Ray event
• only a small fraction of CMEs actually generate
  SCRs
• warning time 10 30 minutes

• Geomagnetic Storms at Earth
• warning time 1-3 days

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Space Radiation Environment - Events

• Solar Flares
• Bright explosion on the surface of the Sun
• Causes
• X-ray burst
• no warning time!
• Solar Cosmic Ray event
• warning time 10-30 minutes

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Space Radiation Environment - Events

• Coronal Holes High Speed Solar Wind Stream
• High speed solar wind streams originate at
  coronal holes
• Causes
• These events often generate geomagnetic storms
  when they are directed toward Earth
• warning time 1-3 day

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Space Radiation Environment Cause
Ionospheric Variations

• Polar Cap Absorption (PCA) Events
• Cause Solar Cosmic Rays
• Absorption of radio waves over the polar caps
• Typically last for two to three days.

• X-ray Absorption Events
• Cause Solar X-rays
• Increased absorption of radio waves on sun-side
• Duration is a few minutes to several hours

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Space Radiation Environment Cause
Radiation Environment - Increases

• Solar Cosmic Ray (SCR) Events
• Ground Level Event (GLE) if increase is observed
  by ground level monitors
• GLEs occur on average once per year (65 between
  1942 and 2004)
• More frequent during solar maximum, less likely
  near solar minimum

• GLEs typically last 6 to 12 hours, but peak
  within 1 to 3 hours
• Very sensitive to altitude and latitude
  variations
• Anisotropy Many SEP events are anisotropic,
  which means that increases vary around the globe
  depending on location

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Space Radiation Environment Cause
Radiation Environment - Decreases

• Forbush Decreases
• Up to a 30 decrease in the dose rate caused by
  CMEs or high-speed solar wind streams blocking
  access of GCRs to the Earth
• High latitudes are effected more than low
  latitudes
• Altitude reductions may be less?
• Lasts on average for 1-14 days

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Space Radiation Environment - Effects
Radiation Damage to Avionics

• Avionics
• Single Event Upsets (SEU), Multiple Bit Upsets
  (MBU)
• 256K SRAM computer withdrawn
• 1 Upset per 200 flying hours in A/P
• 100MB SRAM Upsets/2 hrs, 40,000ft
• 1GB SRAM 1 Upset/minute (SPE 1989)
• Hardware failures
• More Electric aircraft, UAVs

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Space Radiation Environment - Effects
Radiation Damage to Humans

• Humans
• Limit Exposure to Radiation
• - Galactic Cosmic Rays
• - Solar Particle Events
• - Increase radiation at altitude
• SPE 1989 - 2mSv
• SPE 1956 - 10mSv
• Higher, Longer Over-The-Pole
• Commercial Space Flights

Next Generation ? Air Transport
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Space Radiation Environment - Effects
Satellite Navigation

• Cause Magnetic storm, solar cosmic ray event
• Single frequency errors up 20 m in horizontal
  and vertical directions
• Differential GPS reduces error to 1-2 m near
  reference station, but error increases with
  distance from station

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Recent Storm Impacts
Operational Impacts

• Complete or significant loss of comms
• Delays, re-routes or diversions on Polar Routes
• Air Traffic Control imposed flow restrictions
  over Northern Canadian routes and NAT system
• GPS problems
• Increase in fuel costs, loss of Cargo revenue

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Recent Storm Impacts
FAAs Wide-Area Augmentation Systems (WAAS)
The WAAS system was seriously impacted during the
Halloween Storms. For a 15-hour period on
October 29 and an11-hour interval on October 30,
the ionosphere was so disturbed that the vertical
error limit, as defined by the FAAs Lateral
Navigation Vertical Navigation (LNAV/VNAV) to be
no more that 50 meters, was exceeded. That
translated into commercial aircraft being unable
to use the WAAS for precision approaches.
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Recent Storm Impacts
Radiation Impacts - Halloween 2003
FAA Solar Radiation Alert issued for the
following timeframes Start End Duration 10/28
1208 UT 10/29 0603 UT 17h 55min 10/29 2123
UT 10/30 1158 UT 14h 35min 11/02 1808 UT
11/02 2343 UT 05h 35min
Was it correct? Significant Commercial Impact
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Next Generation Air Space Transportation
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The Next Generation Air Transportation
System Joint Planning and Development
Office Where new ideas are welcome
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NGATS 2025 Concept

• Operating Principles
• Its about the users
• System-wide transformation
• Prognostic approach to safety assessment
• Globally harmonized
• Environmentally compatible to foster continued
  growth
• Key Capabilities
• Net-Enabled Information Access
• Performance-Based Services
• Weather-Assimilated Decision Making
• Layered, Adaptive Security
• Broad-Area Precision Navigation
• Trajectory-Based Aircraft Operations
• Equivalent Visual Operations
• Super Density Operations

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Integrating Space Weather into Operations
Policy Research
AMS_SMX Policy Study

• A flight is about to take off from NY to Hong
  Kong. NOAA SEC has recently issued an alert for a
  strong solar radiation storm.
• What does the pilot do?
• What does the airline do?
• What does the air traffic controller do?

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Integrating Space Weather into Operations
Policy Implementation
AMS_SMX Policy Study

• Our understanding of space weather impacts
  risks on the safety efficiency of airline
  operations is growing.
• What should FAA, CAA, EuroControl do?
• What should IATA ICAO do?
• What should the airlines do?
• What should you do?

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QDOS Compact Monitor
Integrating Space Weather into Operations
Policy Risk Analysis
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Components of QARM
Integrating Space Weather into Operations
Policy Modelling

• Models of the Cosmic ray
• Badhwar ONeill model, MSU model, QinetiQ model
• Solar energetic protons
• From GLE neutron monitor data plus GOES
  spacecraft
• Rigidity cut-off code
• MAGNETOCOSMICS/GEANT4
• Response Matrices of atmosphere to energetic
  particle
• Atmosphere Model MSES90, NRLMSES2001
• Particle Transport codes MCNPX, FLUKA, GEANT4

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Integrating Space Weather into Operations
Policy Services
SW Information Alerting System
S.M.A.R.T. Model QinetiQ QARM
Space Weather
Re-planning Optimum Flight Levels (Doses v Ops)
Terrestrial Weather
Aircrew
Aircraft Position
GLMs
ATC Other sources
Detectors
Airline
Airline Ops/Dispatchers
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Summary
Avionics
Communications
Hazard to Humans
Satellite Navigation - Air Traffic Management
(ATM)
R I S K
Technological Development
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Summary

• As our understanding of SW impacts on the
  airlines increases, many people are realising the
  need for a policy framework.
• Emerging issues involve
• Standardization
• Legislation
• Education
• Better information and forecasts
• Better dissemination of products
• Cost/benefit analysis
• We must also consider how these fit within
  current international frameworks for aviation
  safety operations

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Space Radiation Effects on Aircraft
Questions?