Satellite Missions and Satellite Missions and ObservationsObservations

Dan GershmanDan GershmanSHINE Student DaySHINE Student Day

7/10/20117/10/2011

This talkThis talk

OverviewOverview

What makes each spacecraft dataset important?What makes each spacecraft dataset important?

Where can you get all this data?Where can you get all this data?

SummarySummary

Overview of current missionsOverview of current missions

http://science.nasa.gov/missions/

What makes each spacecraft dataset important?What makes each spacecraft dataset important?

Measurement time periodMeasurement time period

Spacecraft locationSpacecraft location

Types of measurements (i.e. types of instruments)Types of measurements (i.e. types of instruments)

Measurement Time PeriodMeasurement Time Period Solar min vs. solar maxSolar min vs. solar max Solar min vs. solar minSolar min vs. solar min Solar max vs. solar maxSolar max vs. solar max Conjunctions with planets, comets, etc…Conjunctions with planets, comets, etc…

It’s hard to cross-calibrate instruments on It’s hard to cross-calibrate instruments on different spacecraft, so ideally we want to different spacecraft, so ideally we want to use the same spacecraft for all of our use the same spacecraft for all of our analysis on a given dataset! (Though this analysis on a given dataset! (Though this isn‘t always possible)isn‘t always possible)

http://www.nswp.gov/ilws/ilws_missions.htm

Spacecraft locationSpacecraft location L1 – first Lagrangian pointL1 – first Lagrangian point

• Outside Earth’s magnetosphere and bow Outside Earth’s magnetosphere and bow shockshock

• Never shadowed by the Earth or the MoonNever shadowed by the Earth or the Moon• Near Earth (R=1AU) observationsNear Earth (R=1AU) observations

solar wind monitorssolar wind monitors

• Examples:Examples: ACE, SOHO, WindACE, SOHO, Wind

Courtesy of Wikipedia

Spacecraft locationSpacecraft location Sun-synchronous Sun-synchronous

• Inside Earth’s bow shockInside Earth’s bow shock• Satellite orbits Earth such that its always Satellite orbits Earth such that its always

at the same local time (i.e., constant at the same local time (i.e., constant view of the Sun!)view of the Sun!)

• Examples:Examples: Yohkoh, TRACE, Hinode, Proba 2, RHESSIYohkoh, TRACE, Hinode, Proba 2, RHESSI

Spacecraft locationSpacecraft location A few others:A few others:

• Geo-synchronous (SDO)Geo-synchronous (SDO) Satellite orbits such that its always above Satellite orbits such that its always above

the same point on Earth, i.e. continuous the same point on Earth, i.e. continuous datastream to the ground!datastream to the ground!

• Earth orbit (IBEX)Earth orbit (IBEX)• Solar orbit Solar orbit

wide variety of heliographic latitudes wide variety of heliographic latitudes (Ulysses)(Ulysses)

wide variety of heliographic longitudes wide variety of heliographic longitudes (STEREO)(STEREO)

wide variety of heliographic radii (Ulysses)wide variety of heliographic radii (Ulysses)• Bounced around through the solar Bounced around through the solar

system (Voyager)system (Voyager) Headed towards the ISMHeaded towards the ISM

http://helio.estec.esa.nl/ulysses/images/third_orbit_2002_rev2006_bigfont.jpg

Ahh… Wikipedia

Types of MeasurementsTypes of Measurements In situ In situ (means ‘in position’ in Latin)(means ‘in position’ in Latin)

• Particle measurements (ions, electrons, neutrals)Particle measurements (ions, electrons, neutrals)• Magnetic field measurements Magnetic field measurements • Measure what’s happening in the heliosphereMeasure what’s happening in the heliosphere

Usually used to compare the output of modelsUsually used to compare the output of models

Remote Sensing/ImagersRemote Sensing/Imagers• Photon measurementsPhoton measurements• Measure what’s happening at the SunMeasure what’s happening at the Sun

Usually used as input for models….Usually used as input for models….

Ion instrumentsIon instruments These instruments give plasma velocities and plasma These instruments give plasma velocities and plasma

composition.composition.

• These typically have one or two sections:These typically have one or two sections: Electrostatic analyzer (ESA) Electrostatic analyzer (ESA) Time-of-flight chamber (TOF) Time-of-flight chamber (TOF)

• Examples: Examples: ACE/SWEPAM, ACE/SWICS, Ulysses/SWICS, STEREO/PLASTIC, ACE/SWEPAM, ACE/SWICS, Ulysses/SWICS, STEREO/PLASTIC,

Wind/3DP, SOHO/CELIAS, and a bunch of others….Wind/3DP, SOHO/CELIAS, and a bunch of others….

Instruments that measure other particles typically work in Instruments that measure other particles typically work in analogous ways, but can have some ionization source (for analogous ways, but can have some ionization source (for neutral measurements) and/or have the polarities of the neutral measurements) and/or have the polarities of the voltages flipped (for electron measurements)voltages flipped (for electron measurements)

Some Relevant Sessions:3. The Role of Magnetic Geometry and Reconnection in the Origin of the Slow Solar Wind 4. Coronal mass ejections without photospheric/chromospheric signatures  5. Multi-viewpoint observations of Solar Energetic Particle (SEP) events7. The Nature of CMEs: Heliospheric properties from remote-sensing observations and their relationship to in situ signatures.  8. Particle Acceleration and Transport in Flares and their Relation to SEP events

http://www.swpc.noaa.gov/ace/

http://solar-heliospheric.engin.umich.edu

Electrostatic AnalyzerElectrostatic Analyzer Makes an electric field that filters out Makes an electric field that filters out

particles based on their E/q.particles based on their E/q.

0V

1kV

Just right!

Too low energy

Too high energy

Time-of-flightTime-of-flight Ion punches through a thin carbon foilIon punches through a thin carbon foil

• Ion is usually neutralizedIon is usually neutralized• A secondary electron is usually createdA secondary electron is usually created

Secondary electron is guided to hit a particle Secondary electron is guided to hit a particle detector (start signal)detector (start signal)

Neutralized ion, which travels a lot slower than Neutralized ion, which travels a lot slower than the electron, later hits a different particle the electron, later hits a different particle detector (stop signal).detector (stop signal).

With a known E/q and velocity of the ion, can With a known E/q and velocity of the ion, can estimate the ion’s m/q. estimate the ion’s m/q. • i.e., E/q = ½ m/q vi.e., E/q = ½ m/q v22

Instruments that calculate composition need a Instruments that calculate composition need a TOF to distinguish between different species, TOF to distinguish between different species, i.e., ACE/SWICSi.e., ACE/SWICS

Instruments that only care about the bulk Instruments that only care about the bulk plasma (which is usually 95% Hplasma (which is usually 95% H++ only need an only need an ESA), i.e., ACE/SWEPAMESA), i.e., ACE/SWEPAM

-1kV

e-

neutralion

Start detector

Stop detector

0V

Carbon foil

Magnetic Field MeasurementsMagnetic Field Measurements Measure vector magnetic fields at high Measure vector magnetic fields at high

(relative to plasma measurements) rates.(relative to plasma measurements) rates.

Typically use ‘fluxgate magnetometer’ Typically use ‘fluxgate magnetometer’ design, which measure currents in coils of design, which measure currents in coils of wire (an inductor) induced by changes in wire (an inductor) induced by changes in the ambient magnetic field. the ambient magnetic field.

ACE/MAG, Wind/MFI, STEREO/IMPACTACE/MAG, Wind/MFI, STEREO/IMPACTSome Relevant Sessions:3. The Role of Magnetic Geometry and Reconnection in the Origin of the Slow Solar Wind 4. Coronal mass ejections without photospheric/chromospheric signatures  7. The Nature of CMEs: Heliospheric properties from remote-sensing observations and their relationship to in situ signatures.  11. The Dissipation of Solar Wind Turbulence  12. The rise of solar cycle 24: Magnetic fields from the dynamo through the photosphere and corona and connecting to the Heliosphere

http://www.swpc.noaa.gov/ace/

Remote Sensing/ImagersRemote Sensing/Imagers SOHO, STEREO, Hinode, SDOSOHO, STEREO, Hinode, SDO

There’s a lot of different photons of interest.There’s a lot of different photons of interest.• Infrared/VisibleInfrared/Visible• UV/EUV/X-raysUV/EUV/X-rays

These observations are line-of-sight (LOS). They These observations are line-of-sight (LOS). They are an integrated measurement along the look are an integrated measurement along the look direction. direction.

Note: You don’t need to be in space to make these Note: You don’t need to be in space to make these observations! observations! • i.e., Kitt Peak, Mauna Loa, Mount Wilson, to name a few i.e., Kitt Peak, Mauna Loa, Mount Wilson, to name a few

((http://en.wikipedia.org/wiki/List_of_solar_telescopeshttp://en.wikipedia.org/wiki/List_of_solar_telescopes ) )

Imaging – Infrared/VisibleImaging – Infrared/Visible Zeeman-splitting – a spectral line can split into Zeeman-splitting – a spectral line can split into

several components (wavelengths/polarizations) several components (wavelengths/polarizations) near a strong magnetic field near a strong magnetic field

This gives measurements of the photospheric This gives measurements of the photospheric magnetic field! (But only LOS)magnetic field! (But only LOS)

SDO/HMI

Some Relevant Sessions:2. Comparing and Validating Models of the Corona and Inner Heliosphere  3. The Role of Magnetic Geometry and Reconnection in the Origin of the Slow Solar Wind 9. Coronal Magnetic Fields: What are we learning from CoMP observations? 10. What IS a coronal hole?  12. The rise of solar cycle 24: Magnetic fields from the dynamo through the photosphere and corona and connecting to the Heliosphere

Imaging – Infrared/VisibleImaging – Infrared/Visible Counting SunspotsCounting Sunspots Total Solar Irradiance (TSI)Total Solar Irradiance (TSI) Observing CMEs with scattered white light from Observing CMEs with scattered white light from

electrons electrons

SOHO/LASCOSOHO/MDI

Some relevant sections:1. Bridging the Great Divide: Linking the Solar Dynamo to the Dynamic Heliosphere6. Assessing the Contribution of Heliospheric Imaging in Improving Space Weather Prediction 

Imaging – UV/EUV/X-rayImaging – UV/EUV/X-ray Different features (coronal holes, flares, active Different features (coronal holes, flares, active

regions, etc..) are more easily seen in different regions, etc..) are more easily seen in different wavelengths:wavelengths:

193nm 304nm 171nm

211nm 131nm 335nm

1700nm1600nm94nm

SDO/AIA

Some relevant sections:6. Assessing the Contribution of Heliospheric Imaging in Improving Space Weather Prediction  7. The Nature of Coronal Mass Ejections: Heliospheric properties from remote-sensing observations and their relationship to in situ signatures.  8. Particle Acceleration and Transport in Flares and their Relation to SEP events10. What IS a coronal hole?  12. The rise of solar cycle 24: Magnetic fields from the dynamo through the photosphere and corona and connecting to the Heliosphere 13. Flare Classification in the Era of Global Coverage of the Sun

Imaging - UV/EUV/X-rayImaging - UV/EUV/X-ray Most spacecraft only see one side of the Sun so Most spacecraft only see one side of the Sun so

we have to wait two weeks to see the other side we have to wait two weeks to see the other side

STEREO A and B recently got far enough apart to STEREO A and B recently got far enough apart to see the whole Sun at once!see the whole Sun at once!

http://stereo-ssc.nascom.nasa.gov/

Where can you get the data?Where can you get the data? Data centers (SPDF, SDAC, VSO)Data centers (SPDF, SDAC, VSO)

http://http://science.nasa.gov/heliophysics/heliophysicsscience.nasa.gov/heliophysics/heliophysics-data-centers/-data-centers/

Mission websitesMission websites• ACE ACE http://http://www.srl.caltech.eduwww.srl.caltech.edu/ACE/ASC//ACE/ASC/ • SOHO SOHO http://sohowww.nascom.nasa.gov/data/ http://sohowww.nascom.nasa.gov/data/ • SDO SDO http://sdo.gsfc.nasa.gov/data/ http://sdo.gsfc.nasa.gov/data/ • STEREO STEREO http://stereo-ssc.nascom.nasa.gov/data.shtmlhttp://stereo-ssc.nascom.nasa.gov/data.shtml

Individual instrument teamsIndividual instrument teams

SummarySummary Satellite missions give us the best (and in Satellite missions give us the best (and in

most cases, the only) measurements of most cases, the only) measurements of the solar and heliospheric environment. the solar and heliospheric environment. • These measurements are vital to advancing These measurements are vital to advancing

our fields of study.our fields of study.• Satellite data will be mentioned in EVERY Satellite data will be mentioned in EVERY

SHINE session at some point.SHINE session at some point.

There are a wide variety of both spacecraft There are a wide variety of both spacecraft and instruments – it can be tricky to find and instruments – it can be tricky to find the right dataset to use!the right dataset to use!