Science Payload Section

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Science Payload Section

• Delicious Science brought to us from the Mars
  Global Surveyor.

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The Mars Global Surveyor Spacecraft

• Two solar panels
• Angular Momentum Management Plan The spacecraft
  uses three reaction wheels, or "flywheels to
  control motion.
• High Gain Antenna
• http//mars.jpl.nasa.gov/mgs/movpics/anim/mgs-beta
  .mpg

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Instruments on Mars Global Surveyor

• MOC
• MOLA
• TES
• Magnetometer
• Mars Relay System (Antenna)
• USO

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Principal Investigators

• MOC Michael Malin, PI
• MOLA David Smith, PI
• TES Phil Christensen, PI
• Magnetometer Mario Acuna, PI
• Radio Science Leonard Tyler, Team Leader

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MOC

• The Mars Orbiter Camera takes pictures that help
  us learn about Mars.
• Primary Mission Objective To map the surface of
  Mars photographically with narrow-angle camera
  shots.

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MOC

• MOC reselected for MGS after failure of Mars
  Observer
• 2 weeks spent making gravity model of Mars
• 9 days spent to calibrate camera and determine
  focus and photometric properties.
• Four phase plan
• 1) Aerobreaking to elliptical orbit
• 2) four weeks of observations from elliptical
  orbit
• 3) 10 weeks observing after 2 week break due to
  solar conjunction
• 4) 6 months of more aerobraking to enter
  circular orbit
• 4/3/1999-1/31/2001 Primary Mission achieved

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MOC Images

• Daily global maps
• Global weather and variable feature monitoring
• 7.5 km/pixel resolution, red and blue wide-angle
  cameras
• Narrow-angle images
• Geology, geomorphology, and variable feature
  monitoring
• 1.5 12 m/pixel resolution
• Context frames
• Wide angle frames acquired with 50 of narrow
  angle images to locate high resolution view
• 240 m/pixel resolution, typically red,
  occasionally blue frames
• Wide-angle images
• Regional monitoring of variable and seasonal
  features
• 240 960 m/pixel resolution, red or blue
  wide-angle images

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MOC

• By photographing the planets surface, we have a
  much better idea what the surface of Mars looks
  like. We can also monitor weather patterns and
  geological changes on the planets surface.

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MOLA(Mars orbiter Laser Altimeter)

• Primary objective
• To determine globally the topography of Mars at a
  level suitable for addressing problems in geology
  and geophysics.

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MOLA

• Secondary objectives
• To characterize the 1064-nm wavelength surface
  reflectivity of Mars to contribute to analyses of
  global surface minerology and seasonal albedo
  changes.
• To assist in addressing problems in atmospheric
  circulation.
• To provide geodetic control and topographic
  context for the assessment of possible future
  Mars landing sites.
• To measure the heights of atmospheric reflections
  to help us better understand the three
  dimensional structure of the Martian atmosphere.
• To attempt to measure the time-varying topography
  of the Martian polar caps.

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MOLA

• Utilizes a spacecraft-fixed (XYZ) coordinate
  system.
• Designed by the Laser Remote Sensing Branch of
  the Laboratory for Terrestrial Physics of NASAs
  Goddard Space Flight Center.
• Internal Instruments
• Laser transmitter
• Collecting mirror (50-cm parabolic)
• Detector (SiAPD)
• Microprocessor
• 0.5 m. Telescope
• TIU (Time interval unit) temperature-controlled
  quartz crystal oscillator

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MOLA

• Absolute accuracy of approximately 30 m.
• Vertical positional accuracy of 1m.
• Horizontal positional accuracy of 100m with
  respect to Mars center of mass.
• Used to map topographic model of Mars based on
  333,689,830 MOLA surface measurements.
• Used to determine best-fit ellipsoid for Mars.
• Current global topographic grid has a resolution
  of 1/64º in latitude by 1/32º in longitude. (1 x
  2 km² at the equator)

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MOLA

• The MOLA lets us map the complex topography of
  Mars with incredible detail.

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The Thermal Emission Spectrometer (TES)
investigation on Mars Global Surveyor (MGS) is
aimed at determining
TES

• (1) The composition of surface minerals, rocks,
  and ices
• (2) The temperature and dynamics of the
  atmosphere
• (3) The properties of the atmospheric aerosols
  and clouds
• (4) The nature of the polar regions
• (5) The thermo-physical properties of the surface
  materials

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The Thermal Emissions Spectrometer (TES) meets
its scientific objectives using these
instruments

• TES

• An Infrared (5.8- to 50-m) Interferometric
  Spectrometer
• A Broadband Thermal (5.1- to 150-m) Radiometer
• A Visible/Near-IR (0.3- to 2.9-m) Radiometer

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Facts about the TES

• TES

• Globally maps surface mineralogy at spatial
  resolution of 3 km.
• Weighs 14.47 kg
• Consumes 10.6 W when operating
• Is 23.6 cm by 35.5 cm by 40.0 cm in size

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TES

• By analyzing the infrared radiation coming from
  Mars, the TES can help us map the mineral
  composition of the surface.

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Magnetometer/Electron Reflectometer
Primary Goal of MAG/ER

• To study the magnetic properties of Mars to gain
  insight into the interior of the planet and
  better understand the early history and evolution
  of Mars.

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Magnetometer

• Measured Mars magnetic field while MGS was at
  altitudes between 100 and 200 kilometers above
  the planets surface.
• Discovered that Mars magnetic field is localized
  in small, particular areas of the crust, rather
  than being centralized.
• Discovered differences between the way Mars
  reacts to solar wind and the way planets with
  strong magnetospheres interact with solar winds.

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Magnetometer

• Measuring the magnetic field of Mars tells us how
  its gravitational field varies, and shows us how
  different it is from Earths.

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Mars Relay System (High Gain Antenna, used in
conjunction with USO)

• Used to
• Transmit messages from Mars rovers to Earth
• Relay information from the Mars Global Surveyor
  itself back to Earth

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High Gain Antenna

• The data sent by the antenna can also be used to
  map variations in Mars gravity field and to
  determine the atmospheric pressure above specific
  locations on Mars.

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USO

• The USO (Ultra-stable oscillator) is a tiny
  device which acts as an electronic clock,
  allowing the spacecraft's radio to broadcast
  signals at an extremely precise frequency.
• The scientists also analyze the electrical
  strength and "tone" of the transmissions received
  as the MGS is about to pass behind Mars, and can
  use these changes in tone to discover
  particularities of the atmosphere the signal is
  being transmitted through.

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USO

• The relay operates at a UHF frequency of 437.1
  megaHertz and can listen to stations on the
  Martian surface up to 5,000 km (3,125 miles) away
  from the MGS.
• Of the six main instruments on the MGS, the Mars
  Relay is the only one not designed to take
  scientific measurements.
• It is designed to collect data transmitted to
  from landers on the Martian surface, and transmit
  it to Earth.

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References

• Pertinent ArticlesMars Global Surveyor Thermal
  Emission Spectrometer experimenthttp//www.agu.o
  rg/journals/je/je0110/2000JE001370/0.htmlMars
  Orbiter Laser Altimeter Experiment summary after
  the first year of global mapping of
  Marshttp//www.agu.org/journals/je/je0110/2000JE
  001364/pdf/2000JE001364.pdfGlobal Distribution
  of Crustal Magnetization Discovered by the Mars
  Global Surveyor MAG/ER Experimenthttp//www.sci
  encemag.org/cgi/content/abstract/284/5415/790Mar
  s Global Surveyor Mars Orbiter Camera
  Interplanetary cruise through primary
  missionhttp//www.agu.org/journals/je/je0110/200
  0JE001455/pdf/2000JE001455.pdfOthershttp//ads
  abs.harvard.edu/cgi-bin/nph-bib_query?bibcode2000
  Sci...287.1788Zampdb_keyASTampdata_typeHTML
  ampformatamphigh45a2b5d64a28490http//adsabs
  .harvard.edu/cgi-bin/nph-bib_query?bibcode1992JGR
  ....97.7781Zampdb_keyASTampdata_typeHTMLamp
  formatamphigh45a2b5d64a28490
• Nasa Website http//mars.jpl.nasa.gov/mgs/
• All pictures taken from NASA website

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Science Objectives

• Characterize the surface features and geological
  processes on Mars.
• Determine the composition, distribution and
  physical properties of surface minerals, rocks
  and ice.
• Determine the global topography, planet shape,
  and gravitational field.
• Establish the nature of the magnetic field.
• Monitor global weather and the thermal structure
  of the atmosphere.
• Study interactions between Mars' surface and the
  atmosphere by monitoring surface features, polar
  caps, and dust and clouds as they migrate over a
  seasonal cycle.

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TES on the Ground

• Found hematite in Meridiani Planum.
• Found that Martian volcanic activity is as
  diverse as Earths.
• Found a new kind of surface material.

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TES in the Air

• Found annual cycles in atmospheric circulation.
• Found that warm dust in the atmosphere prevents
  water-ice clouds.

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MOLA Discoveries

• Measured cloud heights and identified gravity
  waves in the atmosphere.
• Found evidence for and information about water.

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MOLA Maps

• Produced the most accurate global topographic map
  of any planet.

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MOC Discoveries

• Observed repeated weather patterns over three
  northern hemisphere summers.
• Found evidence for water flow over a long period
  of time.
• Photographed new landforms suggesting recent
  underground water.
• Did not find evidence for northern seas.

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• MOC found new craters

January 2004
February 2006
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Dust devil
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