Space Weather (SpW)

7 March 2005 ODTÜ UYDU TKN. 1

Space Weather (SpW)

Near Earth Space Environment (NESE)

Implications for Spacecraft (S/C) Design

Yurdanur Tulunay, Ph.D., Space Research, UK, 1972


keywords-statements

• Spaceweather (SpW)

• NESE interacts with S/C engineering subsystems and payloads

ancient dream

• Traveling among the stars, the planets, moon


Isaac Newton

• 260 years ago had a complete understanding of what was required to

place an object in orbit around E+


1957

• Technological ability to leave the E+’s surface

• First steps in exploration of our solar system


challenge• Difficulty of getting a S/C into orbit

• S/C must be designed to operate in environments that are quite different from

those found on the E+’s surface.


1971-1989

• Database of 2779 S/C anomalies related to interactions with NESE

(The Nat. Geophyl. Data Center, Boulder, Co., USA)

• NASA and AF S/C studies:

~20-25% of all S/C failures are related to NESE (Tribble, 1995)


1993• NASA recognised the importance of the field of NESE by forming a national

program to coordinate a efforts in this area• International Standards Organisation (ISO) under charter from the UN formed a Space

System Technological Comm.one of the missions was to develope

internationaly recognised NESE standards.

(Song, et al., eds., 2001)


1994 June

• 1st doc. by Anderson, B.J. (Ed.)

Natural Orbital Environment Guidelines for use in Aerospace Vehicle Development

NASA Technical Manual


1999 - 2001• Space Weather and the ESA feasibility

studies2003 - 2005

• Space Weather Applications Pilot Project including Service Development Activities (SDA)

(Jansen, et al., 2004)

SWWT 1999 – today• Space Weather Working Team

• European Union (FP5, FP6 and FP7) and Space Weather


• Seek to bridge the gap between space physics and astronautical engineering

►NESE◄

i.e.

Emphasis on the facets of the NESE that may degrade S/C subsystems


objective

To obtain an understanding of the relationship between:

NESE and S/C

or

Space inst., operating principals

and design alternatives.


content

• description of the NESE

• a discussion of the ways in which the NESE may interact with an orbiting S/C

• by relating the various NESE interactions to S/C design specifics


justification Understanding these relationships is important to• S/C designers-must develop a spacecraft

capable of operating in specified orbital environment

• Payload providers-must provide instrumentation capable of delivering

high quality data under potentially

adverse conditions


S/C design

• Regardless of the specific nature of

the payload, all the S/Cs must perform certain basic functions in order to enable the payload to function properly.


finally

A physical structure to accomodate

systems and

payloads


Most S/Cs can be grouped into one of

the three orbital altitude range:

LEO

MEO (HEO)

GEO


• LEO: perigee<1000 km altitude region

space shuttle operates mostly,

typically reserved for

i) largest operational payloads

(e.g. space station-Skylab, Mir, Salyut) or

ii) S/C need a close view of the E+

(e.g. LANDSAT, TIROS, DMSP)


• MEO (or HEO): perigee:1000-2000 km altitude rangee.g. mostly reconnaissance sattelites placed on highly elliptical orbits.

• GEO: altitude 35800 km Popular with various surveillence

and communication S/Cs.


(Tribble, 1995)


• S/C’s orbital altitude

and

• orbital inclination (i). i=f(altitude)

(A given launch vehicle can launch the heaviest possible payload into an inclination=latitude of the launch site)

major impacts on the type and magnitude

of NESE effects experienced by a S/C.


(Tribble, 1995)


(Fortescue, Stark, eds, 1995)

26



conclusion

• NESE may have a direct impact on a S/C subsystem’s ability to execute its design objective.

• Depending on the severity of the orbit, these interactions may be quite mild or may be mission threatening.


SPACE ENVIRONMENTS

VACUUM NEUTRAL PLASMA RADIATION MM/OD

SPACE SYSTEMS

Solar UV

Outgassing & Contamination

Aerodynamic Drag

SputteringAtomic Oxygen Attack

Spacecraft Glow

Spacecraft ChargingVan Allen Belts

Galactic Cosmic Rays

Solar Proton Events

Impacts

Altitute Determination &

Control

Degradition of Sensors

Induced Torques

Change in sensor coating

Interference with sensors

Torques due to induced potentials

Avionics Upsets due to EMI from

arcingDegradition: SEU's, bit errors,...

EMI due to impacts

Electrical PowerChange in coverslide

tranmissions

Change in coverslide transmittance

Shift in floating

potential, reatraction of contaminants

Degradition of solar cell outputDestruction/ Obscuration of solar cells

Propulsion

Thruster plumes may be a contaminant

source

Drag makeup Fuel

Requirements

Shift in floating potential due to thruster firings

Rupture of pressurized

tanks

Structures EMI due to

impacts

Telemetry, Tracking &

Communications

Degradation of sensors

Change in sensor

coatingInterference with sensors

EMI due to arcing Degradition of electronicsEMI due to

impacts

Thermal ControlChange in surface

alpha / epsilon ratio

Change in surface alpha / epsilon ratio

Reatraction of contaminants

Cold surfaces may be experience heating

Degradition of alpha /

epsilon ratio


30Impact

vaporization may stimulate

arcing

Impacts may

expose underlying surfaces to

erosion

Impacts may slightly

increase drag

Impacts may liberate

contaminantsImpactsMM/OD

SPEs suppress

GCRs

Solar Proton Events


Radiation may increase charging

Radiation dose may increase

outgassing

Van Allen Belts

Rad.

Charged surfaces

may increase

sputtering

Spacecraft Charging

Plasma

Spacecraft Glow

AO attack may alter surface

conductivities

AO resistant materials

are susceptable

to glow

AO may clean contaminated

surfaces

Atomic Oxygen Attack

Sputtered material may contanimate sensitivesurfaces

Sputtering

Drag removes OD from

lower orbits

Flow may reflect contaminants to

S/C

Aerodynamic Drag

Neutral

Increases arcing rate

Outgassed material

may contribute to

glow


Solar cycle alters OD density

Induces photoemission

of electronsSolar cycle alters atmospheric densities

Photochemical Deposition of contaminants

Solar UV

Vac.

ImpactsS P

EvenGCR

V A belts

Spacecraft Charging

Spacecraft Glow


SputteringAerodynamic

DragOutgassing & Contamination

S UV

MM/ODRadiationPlasmaNeutralVacuum

Impact vaporization

may stimulate arcing

Impacts may

expose underlying surfaces to

erosion

Impacts may slightly

increase drag

Impacts may liberate

contaminantsImpactsMM/OD

SPEs suppress

GCRs

Solar Proton Events


Radiation may increase charging

Radiation dose may increase

outgassing

Van Allen Belts

Rad.

Charged surfaces

may increase

sputtering

Spacecraft Charging

Plasma

Spacecraft Glow

AO attack may alter surface

conductivities

AO resistant materials

are susceptable

to glow

AO may clean contaminated

surfaces


Sputtered material may contanimate sensitivesurfaces

Sputtering

Drag removes OD from

lower orbits

Flow may reflect contaminants to

S/C

Aerodynamic Drag

Neutral

Increases arcing rate

Outgassed material

may contribute to

glow


Solar cycle alters OD density

Induces photoemission

of electronsSolar cycle alters atmospheric densities

Photochemical Deposition of contaminants

Solar UV

Vac.

ImpactsS P

EvenGCR

V A belts

Spacecraft Charging

Spacecraft Glow


SputteringAerodynamic

DragOutgassing & Contamination

S UV

MM/ODRadiationPlasmaNeutralVacuum

Space Weather (SpW)

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