Lesson 2Lesson 2SpaceSpace

Environment &Environment &Orbital MechanicsOrbital Mechanics

Lesson 2Lesson 2SpaceSpace

Environment &Environment &Orbital MechanicsOrbital Mechanics

A537A537SPACE ORIENTATIONSPACE ORIENTATION

The Space EnvironmentThe Space Environment

Electromagnetic radiation and electrically-charged particles stream outward from the Sun and engulf the Earth. The radiation and particles interact with the Earth’s magnetic field and atmosphere.

Electrically-charged particles

Electromagnetic radiation Magnetosphere

Earth

*Radio Wave

VL

F H

F U

HF

SH

F

Infrared

Ultraviolet

X-ray

GammaWavelength

10-12 meters

10-8 meters

10-7 meters

10-6 meters

0.01 meters

100 meters

0.5 meters

10-3 meters

105 meters

Electromagnetic Spectrumof Solar Energy

* Not all types of radio waves are shown

Causes ionization andheating of atoms and molecules

AM Radio

FM Radio

Causes “traditional” weather

Visible

TROPOSPHERE

STRATOSPHERE

MESOSPHERE

THERMOSPHERE25+ Satellites

RADIATION BELTS25+ Satellites

MAGNETOSPHERE30+ Satellites

DMSP/NOAA

GPS

U-2

SHUTTLE

SEAMLESS

BATTLESPACE

DSPMILSTARDSCSFLTSATGOESComm SATCOM

IONOSPHERE

SPACE WEATHER

Depiction of key environmental regions, examples of satellitescurrently in orbit, and approximate numbers of DoD satellites in orbit in various regions. (Not drawn to scale.)

TERRESTRIAL WEATHER

Earth’s Earth’s MagnetosphereMagnetosphere

Solar Wind

Magnetospheric CurrentsMagnetospheric Currents

InterplanetaryInterplanetaryMagnetic FieldMagnetic Field

Tail Current

Magnetopause

Cusp

Magnetopause Current

Corotating

Ring Current

Field Aligned Current

Neutral Sheet Current

AuroraAurora

Visible light image - particle bombardment

EUV image - auroral oval

The Solar CycleThe Solar Cycle

SolarMinimum

SolarMaximum

0

50

100

150

200

19

54

19

57

19

60

19

63

19

66

19

69

19

72

19

75

19

78

19

81

19

84

19

87

19

90

19

93

19

96

19

99

20

02

20

05

Solar Cycles 19-23 Next Peak: 2000

Solar FlareSolar Flare

An explosive release of energy previously

stored in intense, complex magnetic fields

EHF(Extremely-High Frequency)

Frequency

30 - 300 GHz

3 - 30 GHz

Depiction of Radio Wave Signal Types and the GeneralEffects Caused by the Ionosphere.

VHF(Very-High Frequency)

SHF(Super-High Frequency)

UHF(Ultra-High Frequency)

HF(High Frequency)

MF(Medium Frequency)

VLF(Very-Low Frequency)

LF(Low Frequency)

300 MHz - 3 GHz

30 - 300 MHz

3 - 30 MHz

300 - 3000 KHz

30 - 300 KHz

3 - 30 KHz

SA

TC

OM

GPS

Ionosphere’s Effect

Negligible

SignificantRefraction

Phase and AmplitudeDisruptions

UndisturbedUndisturbedIonosphereIonosphere

Shortwave FadesShortwave Fades

HF radiowave

F

DE

IonosphereIonosphereScintillation

SATCOM DisruptionSATCOM Disruption

SATCOM thresholds•Moderate (partially degraded): 4-12 dB•Severe (SATCOM impossible): >12 dB

Impacts on GPS Navigation Impacts on GPS Navigation SignalsSignals

IonosphereIonosphere

ScintillationScintillation

IonosphereIonosphere

True locationTrue location

Spacetrack ErrorsSpacetrack Errors

Apparent Apparent locationlocation

Radar and SATCOM Radar and SATCOM InterferenceInterference

Radar interference

Radio burstSATCOM

interference

IonosphereIonosphere

Radar InterferenceRadar Interference

AURORAAURORA

Signal reflectedSignal reflected

Spacecraft Spacecraft Charging Charging andand Upsets Upsets • Cause - electrically-charged particle

bombardment, or solar

illumination; combined with

variations in vehicle shape and

materials

• Effect - surface or deep charging

(depends on particle energy)

• Result - electrostatic discharge

(induces an electrical micro-

current)

• Physical damage or logic upset

• Memory loss

• False command

Solar wind

Satellite DisorientationSatellite DisorientationFalse star?

Particle stream (Protons)

Expected trajectory

Launch Trajectory Errors and Launch Trajectory Errors and Payload Deployment ProblemsPayload Deployment Problems

Charged particles

Actual trajectory

Atmospheric Drag - Orbit ChangesAtmospheric Drag - Orbit Changes

Expected positionExpected position

Actual positionActual position

August 1972 Solar FlareAugust 1972 Solar FlareRadiation Hazard

Astronauts on the moon

could have received fatal radiation!

National Space Weather ServicesNational Space Weather Services

• NASANASA

• FAAFAA

• Power companiesPower companies

• ResearchersResearchers

• Ham radio operatorsHam radio operators

• General publicGeneral public

• ArmyArmy

• NavyNavy

• Air ForceAir Force

• MarinesMarines

Dept. of CommerceDept. of Commerce(NOAA)(NOAA)

Space WeatherSpace WeatherOperationsOperations

Boulder, COBoulder, CO

Civilian Customers: Military Customers:

Department of DefenseDepartment of Defense(AF Space Command)(AF Space Command)

55th Space Weather Squadron55th Space Weather Squadron(AF Space Forecast Center)(AF Space Forecast Center)

Falcon AFB, COFalcon AFB, CO

How to Get SupportHow to Get Support

• Request information or support through

your local weather officer or unit

• Support assistance request (SAR) IAW

AFI 15-118, requesting specialized

weather support

SummarySummary

• The near-Earth space environment The near-Earth space environment is neither empty nor benignis neither empty nor benign

• Many space weather hazards can Many space weather hazards can impact military operations in space impact military operations in space and on Earthand on Earth

• Space weather support helps Space weather support helps designers, operators, and users designers, operators, and users optimize mission effectivenessoptimize mission effectiveness

• The near-Earth space environment The near-Earth space environment is neither empty nor benignis neither empty nor benign

• Many space weather hazards can Many space weather hazards can impact military operations in space impact military operations in space and on Earthand on Earth

• Space weather support helps Space weather support helps designers, operators, and users designers, operators, and users optimize mission effectivenessoptimize mission effectiveness