Astronomy 113 Planetary Missions Tuesdays, Thursday 10 am1 pm Kendade Hall 305 Tom Burbine tburbinem

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Astronomy 113Planetary MissionsTuesdays,
Thursday 10 am-1 pmKendade Hall 305Tom
Burbinetburbine_at_mtholyoke.edu
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Website

• www.mtholyoke.edu/courses/tburbine/ASTR113
• All presentations will be available on website
  immediately after class
• So you dont have to copy down everything I put up

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Revised Schedule

• Thursday Jan. 4 -
• Tuesday Jan. 9
• Thursday Jan. 11 -
• Tuesday Jan. 16 Quiz
• Thursday Jan. 18 First 4 Presentations
• Tuesday Jan. 23 Last 5 Presentations

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Mars Missions

• Mariner missions
• Viking 1 and 2
• Mars Global Surveyor
• Mars Pathfinder
• 2001 Mars Odyssey
• Mars Express Orbiter and Beagle 2
• Spirit rover
• Opportunity rover
• Mars Reconnaissance Orbiter

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Homework 3

• Each student should write about the mission that
  they are on
• Names of spacecraft or spacecrafts
• Were they successful?
• Lander or Orbiter?
• When were they launched?
• If Lander, where did it land?
• How long did it take for the spacecraft or
  spacecrafts to reach Mars?
• Who was the PI?
• What instruments were on the spacecraft or
  spacecrafts?
• When did the mission or missions end?
• How much did it cost?

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Homework 4

• Read Rolling Stone Article
• Name 5 reasons why it is difficult to colonize
  Mars

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HW 5Define these terms

• Mineral
• TES
• MOLA
• Calcite
• Complex Crater
• Noachian
• Hesperian
• Amazonian
• Photon
• Triple Point

• Igneous
• Sedimentary
• Basalt
• ALH 84001
• SNC
• Hematite
• Olivine
• Quartz
• Magnetite
• Jarosite

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Quiz next Tuesday

• Know all powerpoints
• Rolling Stone Article
• Videos
• Homework

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Martian Facts

• Revolves around the Sun once every 687 Earth days
  
• Length of a Martian day 24 hours, 39 min., 35
  sec.
• Atmosphere is mostly carbon dioxide (95.3
  percent), nitrogen (2.7 percent), and argon (1.6
  percent)
• Surface winds up to 40 meters per second (80
  miles per hour)
• Surface temperature averages -53 C (-64 F)
• Surface temperature varies from -128 C (-199 F)
  during polar night to 27 C (80 F) at equator
  during midday
• Gravity only 38 percent as strong as Earth's
• Tilt of axis is 25.19 degrees
• Eccentricity of orbit is 0.09

http//athena.cornell.edu/mars_facts/index.html
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Seasons

• Seasons Earth Mars
• (Northern Hemisphere)
• ( in days) (in approx. earth days)
• Spring 93 199
• Summer 94 184
• Fall 89 146
• Winter 89 158

http//www.windows.ucar.edu/tour/link/mars/mars_o
rbit.html
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• Mineral A naturally occurring, homogeneous
  inorganic solid substance having a definite
  chemical composition and characteristic crystal
  structure
• Rock - naturally occurring aggregate of minerals

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Types of Rocks

• Igneous rock that solidified from molten or
  partially molten material
• Metamorphic - rock that has changed in
  composition, mineral content, texture, or
  structure by the application of heat or pressure
• Sedimentary rock formed from material that was
  deposited as sediment by water, wind, or ice and
  then compressed and cemented

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For example

• Basalt grey to black volcanic rock
• Usually contain plagioclase feldpsar and pyroxene
• 45-55 wt SiO2
• 0.5-2.0 wt TiO2
• 4-8 wt MgO
• 14 wt or more Al2O3

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Is ice a mineral?
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Forming Different Mineralogies

• Can be on a planet-scale
• Or a few meters to kilometers

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Some minerals form before other minerals
http//www.gly.fsu.edu/salters/GLY1000/8Igneous_r
ocks/Slide16.jpg
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What minerals form?

• Depends on the composition of the magma
• Depends how quickly the magma cools

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What is the initial composition that the planet
formed from?
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Maybe Solar Composition
http//www.astro.uwo.ca/jlandstr/planets/webfigs/
impacts/images/chondabund.gif
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http//csep10.phys.utk.edu/astr162/lect/sun/compos
ition.html
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http//mars.jpl.nasa.gov/gallery/artwork/20030306a
.html
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Phase Diagram

• One type tells what phases are present at
  particular temperatures and pressures

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Phase diagram
http//mars.jpl.nasa.gov/msp98/mvacs/overview/imag
es/wpd.gif
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Important Minerals on Mars
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Metallic Iron

• FeNi
• Fe0
• Core of the planet

http//rst.gsfc.nasa.gov/Sect19/gib1400.jpg
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Quartz

• SiO2

http//www.geology.neab.net/pictures/rock025.jpg
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Calcite

• CaCO3

http//www.stoneartsofalaska.com/images/crystal20
Kassan20calcite.JPG
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Olivine

• (Mg,Fe)SiO4
• Fe2

http//www.musee.ensmp.fr/mineral//3101.jpg
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Orthopyroxene

• (Mg,Fe)SiO3
• Fe2

http//www.uwm.edu/Dept/Geosciences/Greene_Web_Alb
um/Minerals/images/enstatite_JPG.jpg
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Hematite

• Fe2O3
• Fe3

http//marsrover.nasa.gov/spotlight/images/hematit
e_br.jpg
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Hematite
http//en.wikipedia.org/wiki/Iron28III29oxide

• Fe2O3
• Can precipitate out of water
• 2Fe 3H2O Fe2O3 3H2
• 2Fe2SiO4 2H2O O2 2Fe2O3H2O SiO2
• Can also occur due to volcanic activity
• 4Fe 3O2 2Fe2O3
• 6FeO O2 2Fe3O4 (magnetite)
• 4Fe3O4 O2 6Fe2O3 (hematite)

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Magnetite

• Fe3O4
• Fe2, Fe3

http//www.worldofrockhounds.com/magnetite-crystal
.jpg
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Jarosite

• KFe33(OH)6(SO4)2
• hydrous sulfate of potassium and iron

http//www.news.cornell.edu/photos/jarosite300.jpg
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Basic Definition of Life

• Growth
• Metabolism
• Motion
• Reproduction
• Stimulus response

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ALH 84001

• Allan Hills 84001
• Martian meteorite found in Antarctica
• Thought to have evidence for life (1996)

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Evidence

• organic molecules
• Magnetite (Fe3O4) that looks like it formed from
  biologic activity
• nanofossil-like structures

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Age of ALH 84001

• ALH 84001 - 4.5 billion years
• But has same oxygen isotope ratio as other
  Martian meteorites so it comes from Mars
• Oldest meteorites are 4.56 billion years

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Meteorites from Mars

• Are also called SNCs
• Shergottites, Nakhlites, Chassignites
• Shergotty
• Nakhla
• Chassigny
• 34 Martian meteorites currently known
• http//www2.jpl.nasa.gov/snc/

http//www.amnh.org/exhibitions/permanent/meteorit
es/images/building/nakhla3887.jpg
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How do we know they are from Mars?

• Most have young crystallization ages (1.35 and
  0.15 billion years)
• Gases in glass in the meteorites match Mars

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Crystallization Age

• Crystallization age is measured from when the
  rock cooled and the mineral formed
• Certain unstable isotopes are locked into the
  crystals of the rock, and they begin to decay.

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http//adsabs.harvard.edu/abs/2006LPICo1320...39N
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Viking
http//set.lanl.gov/programs/Mars/Atmosphere.htm
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Oxygen Isotopes
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Shaping Planetary Surfaces

• Impact Cratering
• Volcanism
• Tectonics
• Erosion

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Cratering
Meteor Crater, Arizona
http//www.solarviews.com/eng/tercrate.htm
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Galle Crater, Mars
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Craters

• Tend to be round unless it is an oblique impact

Diameter 85 km Depth 4.8 km
Tycho crater on Moon
http//en.wikipedia.org/wiki/Impact_crater
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Moon
Mars
(180 x 65 km).
(380 x 140 km)
http//www.boulder.swri.edu/bottke/Oblique_crater
s/oblique.html
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Craters
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• Complex craters tend to be larger than simple
  craters

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• Complex Craters
• gravity causes the steep crater walls to
  collapse, which makes complex craters very
  shallow
• Central uplift where the earth rebounds from the
  impact

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Peak Ring Central peak Collapses
Complex
(Melosh, 1989)
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Different types of craters

• http//www.classzone.com/books/earth_science/terc/
  content/investigations/es2506/es2506page07.cfm

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• Small craters are usually much more common than
  larger ones

http//mars.jpl.nasa.gov/gallery/craters/hires/Gus
ev(plain).jpg
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• More craters at smaller sizes - older

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Dating through crater counting(Things to bear in
mind)

• Impact rate and size distribution of impacting
  bodies
• Temporal and spatial variations in impactor
  population
• Temporal variation in the target
• Crater degradation
• Secondary impacts
• Need for measured surface ages to calibrate
  counting

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Calibration

• Moon we have samples from specific places
• Other planets no samples

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http//www.psi.edu/projects/mgs/chron04c.html
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• Cratering rate will be different on Mars compared
  to the Moon
• Mars has larger mass so larger flux
  (gravitational focusing)
• Mars closer to asteroid belt (more possible
  impactors)

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Importance of Craters

• Orbiter You can date the surface
• Rover You can see layers that formed earlier in
  that that are exposed

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Law of Superposition

• layers are arranged in a time sequence, with the
  oldest on the bottom and the youngest on the top,
  unless later processes disturb this arrangement.

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Eagle Crater (picture from opportunity)
http//en.wikipedia.org/wiki/MER-B
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Martian Epochs

• Noachian warm and wet
• Hesperian volcanic
• Amazonian (present day) -cold and dry
• (From crater counting)

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http//www.geo.ucalgary.ca/macrae/timescale/time_
scale.gif
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http//cache.eb.com/eb/image?id73463
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Topography

• The dichotomy of Martian topography is striking
  northern plains flattened by lava flows contrast
  with the southern highlands, pitted and cratered
  by ancient impacts.
• The surface of Mars as seen from Earth is
  consequently divided into two kinds of areas,
  with differing albedo.

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MOLA

• MOLA is the Mars Orbiter Laser Altimeter on Mars
  Global Surveyor (MGS) spacecraft
• This altitude determination process works by
  measuring the time that a pulse of light takes to
  leave the spacecraft, reflect off of the ground,
  and return to MOLA's collecting mirror.
• By multiplying the reflection time by the speed
  of light, scientists are able to calculate
  Surveyor's altitude above the local terrain to
  within 30 meters (98 feet) or better.

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http//www.guidescope.net/solarsys/mars_map2.jpg
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1887-1888
http//en.wikipedia.org/wiki/MarsViewing_Mars
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• Noachian epoch (named after Noachis Terra)
• Formation of Mars to between 3800 and 3500
  million years ago. Noachian age surfaces are
  scarred by many large impact craters. The Tharsis
  bulge is thought to have formed during this
  period.
• Hesperian epoch (named after Hesperia Planum)
• 3500 million years ago to 1,800 million years
  ago. The Hesperian epoch is marked by the
  formation of extensive lava plains.
• Amazonian epoch (named after Amazonis Planitia)
• 1,800 million years ago to present. Amazonian
  regions have few meteorite impact craters but are
  otherwise quite varied. Olympus Mons formed
  during this period along with lava flows
  elsewhere on Mars.

http//www.marsdaily.com/reports/Is_It_Time_For_A_
New_Martian_Chronology_999.html
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Caldera part of volcano has collapsed
Mola Image
http//www.americafree.tv/blogs/2004/12/case-for-w
et-mars-iv-crater-counts-on.html
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Mars Express
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Mars Express
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Noachis Terra Mars Express
http//sci.esa.int/science-e/www/object/index.cfm?
fobjectid39427
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Hesperia Planum Mars Express
http//www.esa.int/SPECIALS/Mars_Express/SEMZLM8A9
HE_0.html
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The clouds result when warm air containing water
vapor rises up the slopes of each volcano, cools
at the higher altitude, and causes the water
vapor to freeze and form a cloud of ice crystals.
http//photojournal.jpl.nasa.gov/catalog/PIA02049
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Mars Moons

• Phobos and Deimos
• Thought to be captured asteroids
• Discovered by Asaph Hall in 1877 at the US Naval
  Observatory in Washington, D.C.
• Phobos mean diameter 22.2 km
• Deimos mean diameter 12.6 km

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Interesting Fact

• In Gulliver's Travels (1726) on the flying island
  of Laputia
• ... discovered two lesser stars, or satellites,
  which revolve around Mars, whereof the innermost
  is distant from the center of the primary exactly
  three of his diameters, and the outermost five
  the former revolves in the space of ten hours,
  and the latter in twenty-one and a half.
• The actual orbital distances and periods of
  Phobos and Deimos are 1.4 and 3.5 Martian
  diameters, and 7.6 and 30.3 hours, respectively.
• No telescope in Swift's day would have been even
  remotely powerful enough to discover these
  satellites.

http//en.wikipedia.org/wiki/Phobos_28moon29
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http//upload.wikimedia.org/wikipedia/en/d/db/Orbi
ts_of_Phobos_and_Deimos.gif
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Phobos
Deimos
Viking orbiter
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Phobos Mars Global Surveyor
Deimos Viking 1 Orbiter
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Instruments

• Remember
• Elements have different numbers of protons,
  neutrons, electrons
• Minerals have different compositions and crystal
  structures
• So different elements and minerals interact
  differently with radiation

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Visible Imager and Infrared Spectrometer
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Everybody in the room reflects light differently

• Different minerals also reflect light differently

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When you look Mars?

• Where does the light from Mars come from?

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• Reflected from the Sun

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Wavelengths

• Micron (µm) 1 x 10-6 meters
• Nanometer (nm) - 1 x 10-9 meters
• Angstrom (Å) - 1 x 10-10 meters

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When a photon strikes a mineral grain

• What happens?

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The photon is either

• Absorbed,
• Passes through the grain, or
• Reflected from a grain surface

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Those that are scattered

• The photons that are scattered
• (reflected from a grain surface or refracted
  through the grain)
• may either encounter another grain or be
  scattered away from the surface

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The photons you measure with a telescope from a
surface

• Are those that have scattered away from the
  surface
• Its called a Reflectance Spectrum

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Albedo

• Refers to the reflectance in the visible
  wavelength region
• At a wavelength of 0.55 µm
• Often called visual albedo

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Since

• Since different minerals have different
  chemistries and/or different crystal structures,
  they will tend to have different reflectance
  spectra

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Infrared

• Vibrational Absorption Features
• http//www.lsbu.ac.uk/water/vibrat.html
• Taken by Thermal Emission Spectrometer (TES)
• Mini-TES is small version

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http//www.psrd.hawaii.edu/Nov03/olivine.html
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RAT

• Rock Abrasion Tool
• Mars is covered with dust so you need to remove
  it to see what rocks underneath look like

http//marsrovers.nasa.gov/spotlight/spirit/200511
21.html
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http//athena.cornell.edu/the_mission/ins_rat.html
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Alpha Particle X-Ray Spectrometer (APXS)

• Emits alpha particles (helium nuclei, consisting
  of 2 protons and 2 neutrons) and x-rays from a
  curium source
• Measures emitted x-rays

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http//www.amptek.com/xrf.html
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http//www.futurescience.org/Mars_Update/a_Mars_ap
xs_capitan.jpg
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Mass Spectrometer

• Identifies different elements by their mass
• Can determine different isotopes

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Mössbauer Spectrometer

• Measures the presence and location of Iron in a
  sample
• Iron in different minerals have different
  absorption peaks

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How it works

• Cobalt-57 (Co57) source
• Decays to iron-57 (Fe57)
• Gives off gamma rays
• Can be absorbed by an Fe atom if it is in the
  same energy state
• Energy state if a function of the environment
  that the Fe atom is in
• If not in same energy state, gamma-ray photon is
  not absorbed
• To change the energy of the gamma-ray photon, the
  source is vibrated (Doppler shifts the photon)

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http//www.mossbauer.org/currenttopic.html
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http//www.mossbauer.org/currenttopic.html
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Magnetometer

• Measures changes in the magnetic field

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Radio Science

• How the spacecraft contacts Earth
• Variations in the orbit of the spacecraft can be
  used to measure the gravitational field
• Can also enable scientists to determine the
  atmospheric pressure at specific locations as the
  spacecraft sends its signal through the
  atmosphere while disappearing behind the planet
  and re-emerging every orbit.

http//mpfwww.jpl.nasa.gov/mgs/mission/sc_instrume
nts.html
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Universal Law of Gravitation

• Every mass attracts every other mass through the
  force called gravity
• Newton came up with this formula
• F G M1 M2
• d2
• M1, M2 are the masses of the two objects
• d is the distance between the objects
• G constant 6.67 x 10-11 m3/(kg?s2)

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Viking Missions

• Missions to Mars that landed in 1976 to look for
  Life
• Viking 1 - July 20, 1976
• Viking 2 - September 3, 1976

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Red Color

• The red color of the planet comes from the
  oxidation of iron minerals in the soil.
• Fe2 is becoming Fe3
• Rusting

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Experiments

• Three of the four experiments to look for life
  produced positive results
• But results could all be explained through
  non-biologic chemistry

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The Labeled Release Experiment (LR)

• Was set up to detect the uptake of a
  radioactively-tagged liquid nutrient by microbes.
  
• The idea was that gases emitted by these microbes
  would show the tagging.
• Initial results were in line with this prediction
  but in the end, the overall results were
  inconsistent.

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The Labeled Release (LR) experiment

• When we consume food, some is processed and
  combined with oxygen to produce energy. Carbon
  dioxide is produced.
• Carbon atoms in the food were radioactive and
  therefore could be detected in the air if a
  creature in the Martian soil processed the food
  and generated carbon dioxide (or some other gas
  containing carbon).
• A radioactive broth was added to a sample of
  Martian soil in a closed chamber.
• A detector in a side chamber measured the amount
  of radioactivity in the air.

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The Pyrolytic Release Experiment (PR)

• Involved "cooking" soil samples that had been
  exposed to radioactively-tagged carbon dioxide to
  see if the chemical had been used by organisms to
  make organic compounds.
• Seven of nine experimental runs seemed to show
  small concentration of micro-organisms but the
  results were later discounted.

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Pyrolytic-Release (PR) experiment

• A mixture of radioactive CO2 and CO was
  introduced into a vessel containing a soil sample
• Sample was irradiated with light
• Then gases flushed out
• Heated
• Detector measured radioactive carbon compound
  given off from heating
• Probably due to non-biologic reactions in soils
  and not life

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Four Science Goals of NASA's long-term Mars
Exploration Program

• Determine whether Life ever arose on Mars
• Characterize the Climate of Mars
• Characterize the Geology of Mars
• Prepare for Human Exploration

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Mars Pathfinder

• Landed July 4, 1997
• Weight - 870 kg
• Lasted 3 months

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Objectives

• Discovery Mission - To prove that the development
  of "faster, better and cheaper" spacecraft is
  possible (with three years for development and a
  cost under US 150 million).
• To show that it is possible to send a load of
  scientific instruments to another planet with a
  simple system and at one fifth the cost of a
  Viking mission.
• To demonstrate NASA's commitment to low-cost
  planetary exploration finishing the mission with
  a total expenditure of US 280 million, including
  the launch vehicle and mission operations.

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Sojourner Rover is investigating Yogi the Rock
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Spirit and Opportunity

• I used to live in an Orphanage.It was dark and
  cold and lonely.At night, I looked up at the
  sparkly sky and felt better.I dreamed I could
  fly there.In America, I can make all my dreams
  come true.....Thank-you for the "Spirit" and the
  "Opportunity" Sofi Collis, age 9

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Spirit
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Husband Hill
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Opportunity
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Opportunity Ledge
Rocks seem layered. Either due to sediments or
volcanic ash
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Hematite (Fe2O3) formed as deposits in water?
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Any Questions?