Post on 31-Jan-2016
description
Space Weather: Why it matters and what we can do about it
16 May 2011
William J. Burke
Air Force Research Laboratory Space Vehicles Directorate
Boston College Institute for Scientific Research
DMSPC/NOFS
CRESS
2
U.S. Space Program: Strategic Perspective
Administration Policy or Treaty
• Eisenhower 1955 - Open Skies Proposal
• Kennedy 1963 - Nuclear Weapons Test Ban Treaty
• Johnson 1967 - Principles Governing the Exploration and Use of Outer Space
• Nixon 1972 - International Liability for Damage Caused by Space Objects
• Carter 1979 - Prohibition of Military or Other Hostile Use of Environment Modification Techniques
MSX
3
Space Weather Overview
Near-Earth space is the very hostile environment in which we mustconduct very expensive operations for both national security and advancing scientific understanding about our star and the cosmos.
• Comparison with severe terrestrial weather
• Solar sources of space climatology and weather:
– Extreme ultraviolet radiation maintenance of the ionosphere and thermosphere
– Solar wind and interplanetary magnetic field coupling to Earth’s magnetic field
– Energy storage and transport in the magnetosphere
depletions that map to image depletions/enhancements on the bottomside.
– Magnetic storms: a big electric circuit in the sky
• Some space weather impacts from an Air Force perspective
– Lost in space Satellite and debris tracking
– Communications and navigation ionospheric irregularities
– Radiation damage to spacecraft components taking control
4
Comparative Meteorologies
• New England Weather
– Hurricane of ‘38
– Blizzard of ‘78
• Comparative Sizes
– Thermonuclear device ~ 1015 Joules = 1 MT
– Solar luminosity 4 x 1026 Joules/s = 400 Billion MT/s
– Solar flux on Earth ~1017 Joules/s = 100 MT/s
– Stormtime power into > 1012 Joules/s = 1 MT/hrupper atmosphere
Solar/space disturbances are just too big to ignore.
5
The Visible and Invisible Sun
Simultaneous views contrasting quiescent photosphere at visible wavelengths with turbulent X-ray emissions of the corona.
6
Coronal Mass Ejection (CME) observed by LASCO white light coronagraph on SOHO
7
SPACE WEATHER EFFECTS:
Solar Wind- Magnetosphere Interactions
7
Solar wind:• Speeds: 300 – 1,000 km/s• Densities: 2 – 100 cm-3
• IMF: 2 - 80 nT• Imposed stormtime potentials on magnetosphere up to 250 kV• Imposed field-aligned currents to ionosphere up to several 10s of MA• Power: several tera (1012) Watts
88
Satellite Drag Environment
Air Force Space Command tracks about 12,800 objects.
About 10% are active payloads.
Others are inactive payloads, rocket bodies and associated debris.
Over 4000 objects are at altitudes below 700 km where aerodynamic drag is significant.
9
Two Major Space Weather Effects
Degradation/loss of signals
C/NOFS
Satellite/debris drag
CHAMP
Actual Position
Predicted PositionProblems
Responses
10
Magnetic Storm Effects
Creation of a new radiation belt by a shock wave during the March 1991 magnetic storm
11
Never has so much depended on something so small!
Current US policy calls for use of commercial off-the-shelf micro-electronics on all future spacecraft.
Tradeoff: Cost versus reliability/survivability
1/4
Chip in the eye of a needle
12
Space Situation Awareness
Compact Environmental Anomaly Sensor (CEASE)
13
Mitigation of Space Hazards
• Use available monitors to predict magnetic storms
• Automate situation awareness for satellites
– Radiation environment monitors - CEASE
– Spacecraft discharging
• Control radiation belt fluxes
– Number of energetic particles not large
– Give nature a helping hand: ELF/VLF antennas in space
14
High Altitude Nuclear Detonation (HAND)Impacts Multiple Systems
• High-altitude nuclear tests of 1958 and 1962 demonstrated wide-area affects. Significant military system impacts
– Radars: Blackout, absorption, noise, clutter, scintillation
– Communications: Blackout, scintillation fading, noise, connectivity
– Optical Sensors: IR, Visible, UV backgrounds, clutter; radio noise
– Satellites: Trapped radiation; radiation damage to electronics
– Electronics & Power: Electromagnetic pulse; electrical systems damage
STARFISH1.4 MT at 400 km
ORANGE 3.8 MT at 43 km
KINGFISH__ MT at __ km
TEAK3.8 MT at 76.8 km
CHECKMATE__ MT at __ km
15
HAND Belt50 kT, 31.3 deg, 75.2 deg, 200km
Nuclear vs Natural Environment (~800km Polar Orbit)
1E+01E+11E+21E+31E+41E+51E+6
1 14 30 365Days
Do
se
(R
ad
s S
i)
NuclearNatural
High Altitude Nuclear Detonation produces huge increase in radiation for satellites – all LEO spacecraft fail within months – Devastating to our military intelligence, national security and world economy!
High Altitude Nuclear DetonationWhat is the problem?
900
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60 70 80
Blu
e L
EO
Sat
elli
tes
Ali
veIn
clu
des
nat
ion
al, m
ilit
ary
and
com
mer
cial
30 KT, 500 km
10 KT, 300 km20 KT150 km
500 KT 125 km
Days into Campaign
Blue satellite attrition curvesSource: AFRL/VSES
16
Physics of Pitch-Angle Scattering
ELF/VLF Waves Control Particle Lifetimes
L shell = distance/RE
17
Key scientific questions:Wave-particle scattering: Are interactions diffusive or coherent? Can tailored wave forms improve efficiency?
Global wave propagation and amplification: Where does wave power go in the far field? Can waves be amplified through plasma processes?
ELF-VLF wave injection efficiency: Can ground-based antennas radiate VLF efficiently through the ionosphere? Can space-based antennas radiate VLF into the far-field at high power levels?
VLF wave generation
Wave propagation
Wave-particle interaction
Ionosphere
Outer-zone electrons
HAND belt electrons
Radiation Belt Remediation (RBR)Radiation Belt Remediation (RBR)
Mission: Understand the physical methods of remediating an enhanced radiation belt as a result of a HAND using VLFPayoff: LEO space asset lifetimes are extended and the reverts the radiation environment to acceptable levels for spacecraft replenishment following attack
18
Thin Film Photovoltaics• 10X more Available Power• Enables 50 – 100kW range• High radiation tolerance and
thermal annealing
Radiation-Belt Remediation• 50-m Boom & Truss used for VLF
transmit & receive antenna• Actively counter effects of Solar Storms
or HAND
System ID & Adaptive Control• 60X decrease in structural dynamics• ACS autonomously corrects for structure changes due to radiation, failure, etc• Enabling technology for future lightweight structures
25-m
16-m
5-m
25-m
6000-km x 12000-km MEO orbit
Cygnus (DSX)Functional Baseline
Goal: Remove Power, Aperture, and MEO as constraints to DoD Space Capability
Transformational Deployed Structures• 25-m Boom• 25-m Truss• Roll-out Solar Array structure
Space Weather Sensor Array• Data for models in critical orbit• Validate Radiation-Belt Remediation• Correlate Structures and PV radiation
effects
19
CLUSTER observations of HAARP VLF signals – 26 Jan 03
3.125 kHz
3.375 kHz
“First light” from conjugate point VLF buoy
RBR Phase 1 Results:VLF from HAARPRBR Phase 1 Results:VLF from HAARP
HAARP experiments are crucial to understand VLF injection/amplification in the magnetosphere– a key enabler for an operational mitigation system
HAARP experiments are crucial to understand VLF injection/amplification in the magnetosphere– a key enabler for an operational mitigation system
Initial 2-hop >10 dB amplification – steady amplitude for next several hops!
HAARP ionospheric heating facility
2-hop 4-hop 8-hop6-hop 10-hop
One experiment complete before HAARP down for antenna-build
20
Some Conclusions
• U.S. enjoys vast superiority in space operations.
• Sensors and electronics on space-based platforms are
vulnerable to solar-induced hazards.
• Our experience in space is still quite limited.
– Can satellites survive the solar storm of the century?
– Warnings reduce RISK.
– Space weather forecasting is a necessity.
– Engineers must know why anomalies occur.
– Radiation control gives nature a helping hand.
21
Backup Pictures
AF Geospace
Radar Clutter Map
SATCOM Outage Map
DMSP Models
22
Backup Pictures
23
Hazards to Space Systems
Space Particle Hazards
• Radiation degradation and electronics upsets• Surface and internal
charging / discharging
Ionospheric Hazards
• Comm/Nav link degradation and outage• Surveillance clutter• Satellite Drag
Adversary-Induced Hazards
• High energy particles• RF Waves
Direct Solar Hazards
• Radio, optical and X-ray interference• Solar energetic particle
degradation and clutter