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Albedo and MultispectralAlbedo and MultispectralProperties of Rocks and Soils atProperties of Rocks and Soils atGusev and Meridiani from theGusev and Meridiani from the
Mars Exploration Rover PancamMars Exploration Rover PancamImaging SystemsImaging Systems
Jim Bell (Cornell University)Jim Bell (Cornell University)Representing the Athena Science TeamRepresenting the Athena Science Team
Presented May 25, 2005 at the AmericanPresented May 25, 2005 at the AmericanGeophysical Union Spring Meeting,Geophysical Union Spring Meeting,
New Orleans, LANew Orleans, LA
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
OutlineOutline•• Gusev and Meridiani Color and AlbedoGusev and Meridiani Color and Albedo•• Visible to Near-IR Spectral UnitsVisible to Near-IR Spectral Units
–– Rocks, Rocks, clastsclasts, soil, dust, and other, soil, dust, and othermaterialsmaterials
–– Comparison with previous measurementsComparison with previous measurements–– Mineralogic implicationsMineralogic implications
•• Update on Latest Measurements...Update on Latest Measurements...
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Pancam SummaryPancam Summary
Bell Bell et al., JGRet al., JGR, Dec. 2003, Dec. 20031024x10241024x1024CCD arrayCCD array
•• Two CCD cameras per rover Two CCD cameras per rover•• Stereo separation 30 cm Stereo separation 30 cm•• 1024 1024 ×× 1024 pixel images 1024 pixel images•• Focal length 42 mm, Focal length 42 mm, ff/20/20•• Resolution = 0.28 Resolution = 0.28 mrad mrad/pixel/pixel•• Field of view: 16 Field of view: 16°° ×× 16 16°°•• 8 filters/eye, 400-1050 nm 8 filters/eye, 400-1050 nm•• Onboard calibration target Onboard calibration target•• Wavelet image compression Wavelet image compression•• Some onboard image processing Some onboard image processing
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Pancam Data SetsPancam Data Sets•• MER-A MER-A ““SpiritSpirit””
–– 33,248 images as of Sol 493 (3.20 33,248 images as of Sol 493 (3.20 GBytes GBytes of raw data)of raw data)–– Eight 360Eight 360°° color panoramas acquired color panoramas acquired–– About a dozen more very large color panoramasAbout a dozen more very large color panoramas–– Hundreds of 11-color multispectral spotsHundreds of 11-color multispectral spots
•• MER-B MER-B ““OpportunityOpportunity””–– 31,624 images as of Sol 473 (2.93 31,624 images as of Sol 473 (2.93 GBytes GBytes of raw data)of raw data)–– Five 360Five 360°° color panoramas acquired color panoramas acquired–– About ten more very large color panoramasAbout ten more very large color panoramas–– Hundreds of 11-color multispectral spotsHundreds of 11-color multispectral spots
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Albedo:Albedo:Gusev and MeridianiGusev and Meridiani
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Pancam“Albedo”
Panoramas
“Albedo” is estimated by dividing the I/F determined from observations calibrated using the onboardcalibration target by the cosine of the solar elevation angle at the time of each observation. This albedoestimate should be comparable to bolometric Lambert albedo values derived from orbital observations.
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Gusev AlbedoGusev Albedo
Average:Average:0.25 0.25 ±± 0.05 0.05
TES TES AvgAvg::0.23 0.23 ±± 0.03 0.03
Dark StreakDark StreakAverage:Average:
0.20 0.20 ±± 0.02 0.02
Bright SoilBright SoilAverage:Average:
0.30 0.30 ±± 0.02 0.02Sol 66 Bell et al.,
Science, 305, 800 (2004)
MGS/MOC
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Meridiani AlbedoMeridiani Albedo
Average Plains: 0.12 Average Plains: 0.12 ±± 0.01 0.01TES Landing Pixel: 0.12 TES Landing Pixel: 0.12 ±± 0.03 0.03
Bright Outcrop Average: 0.25 Bright Outcrop Average: 0.25 ±± 0.06 0.06Bright Plains Wind Streaks: 0.19 to 0.29Bright Plains Wind Streaks: 0.19 to 0.29
Bell et al., Science, 306, 1703 (2004)
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Terra Nova
OpportunityOpportunitytraversing traversing
south...south...
1 km
Sol 4003/10/05
Sol 4605/10/05
Sol 1
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Meridiani plains albedo: Sol 442 (Apr. 22)Meridiani plains albedo: Sol 442 (Apr. 22)
Looking south... Looking north...
Average albedo of plains: 0.158±0.016
Average albedo: 0.157±0.014 Average albedo: 0.157±0.013(not including tracks)
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Meridiani plains albedo: Sol 454 (May 4)Meridiani plains albedo: Sol 454 (May 4)
Looking south... Looking north...
Average albedo of plains, ~100 m farther south: 0.156±0.016
Average albedo: 0.155±0.012 Average albedo: 0.157±0.014(not including tracks)
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
MultispectralMultispectralProperties atProperties at
GusevGusev
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
SpiritPancam
ColorPanoramas
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Spectral diversity of Gusev rocks and soilsSpectral diversity of Gusev rocks and soils
sol 220“Toltecs”
sol 293“Uchben”
sol 332“Wishbone”
sol 492“Larry’sOutcrop”
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Gusev Spectral DiversityGusev Spectral Diversity
E
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Visible to Near-IR Spectral Classes•• Wide range of I/F values Wide range of I/F values•• Everything has a strong Everything has a strong
ferric absorption edgeferric absorption edge(except RAT holes)(except RAT holes)
•• Soil spectra Soil spectra ““dust-likedust-like””- - nanophase nanophase ferric iron dominatesferric iron dominates
- minor - minor ““crystallinecrystalline”” ferric component ferric component•• Dark rock spectra have a Dark rock spectra have a
negative near-IR slope and anegative near-IR slope and awell-defined ferrous bandwell-defined ferrous band
- - ““basalticbasaltic”” signature signature - consistent with - consistent with px px oror ol ol
Bell et al., Science, 305, 800 (2004)McSween et al., Science, 305, 842 (2004)
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Visible to Near-IR Spectral Classes•• Wide range of I/F values Wide range of I/F values•• Everything has a strong Everything has a strong
ferric absorption edgeferric absorption edge(except RAT holes)(except RAT holes)
•• Soil spectra Soil spectra ““dust-likedust-like””- - nanophase nanophase ferric iron dominatesferric iron dominates
- minor - minor ““crystallinecrystalline”” ferric component ferric component•• Dark rock spectra have a Dark rock spectra have a
negative near-IR slope and anegative near-IR slope and awell-defined ferrous bandwell-defined ferrous band
- - ““basalticbasaltic”” signature signature - consistent with - consistent with px px oror ol ol•• Consistent with telescopic Consistent with telescopic
and Pathfinder spectraand Pathfinder spectra•• Except for Except for ““whitewhite”” places... places...Bell et al., Science, 305, 800 (2004)McSween et al., Science, 305, 842 (2004)Mustard & Bell, GRL (1994); Bell et al., JGR (2000)
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Sol 381A“Peace”
10 cm
Sol 431A“Paso Robles”
10 cm
10 cmSol 400A“Paso Robles”
High Sulfur deposits!High Sulfur deposits!
Sol 381A“Peace”
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Sol 399, P2550
Undisturbed soil
Bright soils
Spectra reveal much weaker ferricSpectra reveal much weaker ferricabsorption signature...absorption signature...
J. JohnsonJ. Johnsonet al., et al., 20052005
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Undisturbed soil
Bright soils
673 nm maximum
...as well as higher reflectance and...as well as higher reflectance anda reflectance peak near 673 nm.a reflectance peak near 673 nm.
J. JohnsonJ. Johnsonet al., et al., 20052005
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
BD530bMorris et al., 2000
Pancam spectral parametersPancam spectral parametersindicate general consistencyindicate general consistencywith Fe,S-rich Mars analogwith Fe,S-rich Mars analogmaterials studied by Morris materials studied by Morris etetal.al. (2000) and others, but need (2000) and others, but needmore information to choosemore information to chooseamong possible sulfates...among possible sulfates...
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
MultispectralMultispectralProperties atProperties at
MeridianiMeridiani
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
OpportunityPancam
ColorPanoramas
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Meridiani Spectral UnitsMeridiani Spectral Units
Opportunity: Sol 20False color compositeScene is ~ 50 cm wide
Bell et al., Science, 306, 1703 (2004)
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
Meridiani Spectral UnitsMeridiani Spectral Units
Opportunity: Sol 68 13:00False color compositeScene is ~ 40 cm wide
Bell et al., Science, 306, 1703 (2004)
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
•• Wide range of I/F values in Wide range of I/F values in““dustdust”” and and ““sandsand””
Visible to Near-IR Spectral Classes
Bell et al., Science, 306, 1703 (2004)
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
•• Wide range of I/F values in Wide range of I/F values in““dustdust”” and and ““sandsand””
•• These simple classes are These simple classes are~ consistent with telescopic~ consistent with telescopicand Pathfinder spectraand Pathfinder spectra
Mustard & Bell, GRL (1994); Bell et al., JGR (2000)Bell et al., Science, 306, 1703 (2004)
Visible to Near-IR Spectral Classes
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
• Wide range of I/F values in“dust” and “sand”
• These simple classes are~ consistent with telescopicand Pathfinder spectra
• But there are many otherunique spectral classes!
Mustard & Bell, GRL (1994); Bell et al., JGR (2000)Bell et al., Science, 306, 1703 (2004)
Visible to Near-IR Spectral Classes
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
• Wide range of I/F values in“dust” and “sand”
• Everything has a strongferric absorption edge(except RAT holes)
• But there are many otherunique spectral classes!
• Nanophase ferric (?) outcrop• Crystalline ferric blueberries• Hematite-rich (?) plains• Olivine-pyroxene rich rock• “Gray” (Hm?) cobbles
Bell et al., Science, 306, 1703 (2004)
Visible to Near-IR Spectral Classes
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
CalibrationCalibration•• Pancam cal target observationsPancam cal target observations
•• Provides a quick estimate of reflectanceProvides a quick estimate of reflectance•• Precision Precision ≤≤ 3%; Accuracy ~10-15% 3%; Accuracy ~10-15%
•• But targets are getting dusty...But targets are getting dusty...•• Our model uses lab data and the sweep magnetOur model uses lab data and the sweep magnet’’s s ““cleanclean
spotspot”” to estimate a dust correction for deriving I/F to estimate a dust correction for deriving I/F
Sol 2A Sol 55A Sol 2A Sol 55A Sol 150A Sol 150A Sol 302A Sol 302A SpiritSpirit Pancam calibration target images Pancam calibration target images
Spirit self-portraitSols 329, 330A few words about...A few words about...
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
But the dust has sometimes beenBut the dust has sometimes been““cleanedcleaned”” by the wind... by the wind...
more.... more.... more... more... more... less!more... more... more... less!
more.... more... less... more... more...more.... more... less... more... more...
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
SpiritSpirit Pancam temperature history... Pancam temperature history...
CCD
Electronics
A Sol: 1 50 100 200 300 400 500A Sol: 1 50 100 200 300 400 500
Spirit
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
OpportunityOpportunity Pancam temperature history... Pancam temperature history...
CCD
ElectronicsOpportunity
B Sol: B Sol: 1 50 100 200 300 400 5001 50 100 200 300 400 500
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
SummarySummary•• There is a wide variety of 400 to 1100 nm visibleThere is a wide variety of 400 to 1100 nm visible
color and near-IR spectral variation in the rockscolor and near-IR spectral variation in the rocksand soils at Gusev and Meridianiand soils at Gusev and Meridiani
•• Two spectral classes at both sites are consistent Two spectral classes at both sites are consistentwith previous telescopic and MPF/IMP data:with previous telescopic and MPF/IMP data:–– A bright A bright ““globalglobal”” dust component in all soils dust component in all soils–– A dark A dark ““global basalticglobal basaltic”” sand component sand component
•• Other unique spectral classes identified, and canOther unique spectral classes identified, and canbe related to variations in Fe, S mineralogybe related to variations in Fe, S mineralogy
•• Lots of calibrated radiance data have beenLots of calibrated radiance data have beenreleased to the PDS, much more to come...released to the PDS, much more to come...
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
MER Data Sets
• MER-A “Spirit”• As of sol 493 (May 24)• 47,949 total images• 45.0 total Gbits (5.6 GB)• 33,248 Pancam images• 2,509 MI Images• millions of MiniTES spectra• 85+ APXS rock/soil spectra• 83+ MB rock/soil spectra• 14+ RAT holes (48 brushes)• Odometry as of 5/24: 4368 m
• MER-B “Opportunity”• As of sol 473 (May 24)• 44,047 total images• 42.8 total Gbits (5.4 GB)• 31,624 Pancam images• 2,706 MI Images• millions of MiniTES spectra• 71+ APXS rock/soil spectra• 91+ MB rock/soil spectra• 22+ RAT holes (9 brushes)• Odometry as of 5/24: 5346 m
Jim Bell (Cornell University) 2005 AGU Spring Meeting, New Orleans, LA
