Robin Fergason Philip Christensen MSL Landing Site Selection Workshop May 31, 2006

Determining surface characteristics at candidate MSL landing sites using THEMIS high-resolution orbital thermal inertia data
Robin FergasonPhilip Christensen
MSL Landing Site Selection WorkshopMay 31, 2006

Thermal Inertia BackgroundUsed to infer a particle size of the surface layer
Helps to identify features, their location and extent on the surface, and their particle size
Detect exposed bedrock and dust

Exposed Bedrock80026067.6 ENili Patera66.9 E8.7 N9.5 NAres VallesRogers et al., 2005Christensen et al., 2003a; 2005950190341.6 E341.3 E5.9 N6.4 N3.4 km3.5 kmTHEMIS-derived thermal inertia overlain onto THEMIS visible

Hebes Chasma Interior Layered DepositsV10052001800 mTI: 190-245TI: 275-360TI: 290-420TI: 125-145125615Fergason et al., submitted

Thermal Inertia BackgroundI = (kc)1/2 bulk density k conductivity c specific heatThermal inertia measures a materials resistance to change in temperature

THEMIS-derived thermal inertiaUse thermal model developed by H. H. KiefferLs, latitude, local time from spacecraft ephemerisTES-derived albedo (8ppd)MOLA-derived elevations (128 epd)TES-derived dust opacity (2 ppd) every 30 LsRadiance at 12.57 m (Band 9) is converted to brightness temperature, correcting for drift and wobble of the spacecraftInterpolate upon a 7-D look-up table

THEMIS-derived Thermal Inertia UncertaintiesUncertainties are primarily due to: (1) instrument calibration (2) uncertainties in model input parameters (3) thermal model uncertainties
Variations in thermal inertia within a single image are accurate and represent differences in the physical properties of the surface

Comparison with TES25600180 E40 S40 N180 E180 E40 S40 N180 ETHEMISTES Fergason et al., submitted

Comparison of Mini-TES and THEMISThermal InertiaFergason et al., 2006250430
Chart2
168.16280
157.09300
192.93330
150.12305
197.5175290
136.43225315
216.638350
487.788390
668.1165
1206.98
436.476
336.216
351.142
205.595
196.736
363.331
235.513
257.435
227.187
220.189
164.327
294.06
275.998
284.769
759.402
352.24
178.753
240.203
276.633
338.538
176.183
Mini-TES Thermal Inertia
THEMIS Thermal Inertia
Spirit - Gusev Landing Site Number
Thermal Inertia
THEMIS and Mini-TES Thermal Inertia
Sheet1
Gusev Plains Traverse
Comparing THEMIS and Mini-TES thermal inertia data results
THEMIS Thermal InertiaMini-TES Thermal InertiaMini-TESTHEMIS
SolAvg SolAve SiteFeatureAvg THEMIS thermal inertiaAvg Mini-TES thermal inertiaAlbedo - 0.25Albedo - 0.22Albedo - 0.22 - minus the outlying high values to calculate an appropriate standard deviation
Albedo 0.25Alb 0.22siteSolinertiainertia
1-50254plains280140173325133.71168.16280168.16
51-615612transition between plains and Bonneville crater300190134437124.62157.09284157.09
61-897520Bonneville ejecta330380774744161.49192.93288192.93
90-1009526transition between plains and Bonneville crater305300301946125.952150.12292150.12
101-12311236Lahonton Crater2901852441050146.677197.5175296173.1635197.5175
124-13312848plains315195196115282.13136.43225300136.43225
138-15014456plains3503103071261185.56216.638310133.845216.638
150-15815464near Colombia hills3902402641362419.42487.788320487.788
1565697.01668.1165330436.476
RMS between THEMIS and MT24891206.981206.98321.7263.8658055556774.47336.216
2590315436.476313.4358.177225351.142
2691286.22336.216305205.595
2799304.56351.142302.5301.9266666667196.736
28101176.25205.595300363.331
29102167.465196.736297.5235.513
31106313.82363.331295257.435
33109202.17235.513292.5227.187
36112217.12257.435290220.189
39118183.54227.187295164.327
42122186.25220.189300243.7122857143294.06
44124129.42164.327305275.998
46125294.06294.06310284.769
48128239.5275.998315352.24
50130121.94284.769326.6196.23178.753
55143567.46759.402338.2240.203
57145300.95352.24350276.633
59147152.72178.753363.3338.538
61149207.967240.203376.6307.27425176.183
64153239.112276.633390
71189293.93338.538
73191147.75176.183293.8536190476263.7846666667
6170.926
314.6031693548313.3551724138
218.72087890789.0118269262
RSS
Bonneville to CH RSS:319.5983309972Mini-TESBonneville to CH RSS:
331.9487912314THEMIS
12.3504602342
Sheet1
Spirit - Gusev Landing Site Sol Number
Thermal Inertia
Sheet2
Spirit - Gusev Landing Site Number
Thermal Inertia
Sheet3

Landing Site CharacterizationIdentify regions of very high or very low thermal inertiaTI > 400 likely has rocky surface [Nowicki, 2006]TI < 100 is likely dusty and not drivableEvaluate surface properties of the candidate landing sitesPredicted surface temperature for the primary missionRover design temperature limits: 145 - 310 KMaximum diurnal temperature range: 145 K

Opportunity THEMIS Temperature Mosaic - 2003

Opportunity THEMIS Temperature Mosaic - 2006

63.2 E57017526.8 N26.3 N62.6 EFergason et al., submitted

THEMIS Day and Night IR

Predicting Surface TemperatureThermal inertia is derived from THEMIS imageThe derived thermal inertia value is then used to calculate the surface temperature for a given local time and season
Can predict the minimum surface kinetic temperature during the primary mission

ASU Will ProvideInterpretations of THEMIS and TES thermal inertia data for all candidate landing sites
Thermal inertia mosaics of candidate landing site regions (100 m)Relative thermal inertia values

ASU Will ProvideIndividual thermal inertia images of specific areas of interest (100 m)Thermal inertia values of specific morphologies
Predicted temperature maps of candidate landing site regions (100 m)Predict range of temperaturesDerive maximum diurnal temperature range