HIGHER THAN ADVERTISED MARTIAN AIR PRESSURE Part 1: Overview of - - PowerPoint PPT Presentation

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HIGHER THAN ADVERTISED MARTIAN AIR PRESSURE Part 1: Overview of Pressure Measurement Issues

By David A. Roffman, Embry-Riddle Aeronautical University

http://DavidARoffman.Com Presented at the 14th International Mars Society Convention, Dallas, TX

August 4, 2011

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Accepted Average Pressure 6.1 Mbar at Mars Areoid

 Areoid is Mars equivalent of Sea Level.

 Average Earth sea level pressure = 1013.25

Mbar.

 6.1 Mbar is nearly a vacuum (= pressure on

Earth at 90,417 feet/27,550 meters)

• View from a MIG 25 at 83,600 feet,
• Pressure = ~11.3 mbar

Why Question Accepted Pressure?

 Initial stimulus - similarities in Martian &

Terrestrial dust devils.

http://www.lpl.arizona.edu/~lemmon/mer_dd/dd_enhanced_587a.gif

 Scope of Research: 2 yr. study, special topics

course at ERAU, literature & NASA Ames Archives review, interviews of pressure transducer designers, Viking data audit.

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Why Question Accepted Pressure?

Mars dust devils typically have speeds of 6m/s (~13 MPH), but during an Ames experiment at 10 mbar, a wind speed of 70 m/s (~156 MPH) was needed to form a dust devil.

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Why Question Accepted Pressure?

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Why Question Accepted Pressure?

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• No way to change small dust filters on

Vikings, Pathfinder, or Phoenix! Rapid clogging likely.

Only Viking-2 provided published pressure data for over a Martian year

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Problems with Viking Pressures

When pressures weren’t stuck, they varied with laws for gases in sealed containers (not in contact with the ambient air of Mars).

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First Photo From Mars Shows How Dust Affected Viking 1!

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Greeley et al. (1992): ”In designing future lander spacecraft for Mars, consideration must be given to the infiltration of fine dust into spacecraft components…” Since dust makes its way in at the air intake tube for the pressure sensor – start there!

Why Question Accepted Pressure?

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Dust storms enormously increase opacity and atmospheric density. Can block 99% of light.

Dust Storm of July 5, 2011 Phoenix, Arizona

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Pressure at nearby Luke Air Force Base increased during the dust storm by 6.6 mbar – that’s more than average pressure (6.1 mbar) at areoid on Mars.

Why Question Accepted Pressure?

 Last 4 successful landers long (downrange) by

13.4 - 27 km (request for help from NASA’s Prasun Desai, 2008)

 3 landers “lost” might have been short (Mars

Polar Lander & Deep Space 2 in 1999; Beagle 2 in 2003)

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Why Question Accepted Pressure?



MPF anemometers could not be calibrated.

 Path  No anemometer on Phoenix.

Telltale could not measure speeds >10 m/s and

• nly had 20 - 40% accuracy for winds <10m/s.

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Pathfinder Windsock mast

MPF Thermal wind sensor

Why Question Accepted Pressure?

 Snow. Ice particles in clouds an order of

magnitude too small for GCMs – 2 μm vs. 20 to 30 μm (Richardson, et al., 2002)

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DUST DEVILS ARE THE MOST OBVIOUS WEATHER ANOMALY

 If there is so little air on Mars, how can

there be enough Δp to generate them at all?

 Over 30 dust devils hit

the Phoenix lander in just 150 days. Pathfinder detected ~79 in 86 days.

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Similarities between Terrestrial and Martian Dust Devils

• Seasons (summer on Earth,

spring and summer on Mars)

• Electrical properties

(0.8 MV for a terrestrial event).

• Shape & often size (but

can be 50 x wider and 10 x higher on Mars)

• Daily formation times (around noon)

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Similarities between Terrestrial and Martian Dust Devils

• wind speed (6 m/s typical)
• core temperature increase (up to 10 K)
• dust particle size (1 μm typical). But with

low 6.1 mbar pressure, 500 m/s (1,118 mph) wind required to lift 1 μm dust. (Read & Lewis, 2004)

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Differences between Terrestrial and Martian Dust Devils – mainly Absolute and Relative Pressure Excursions

 Maximum pressure drop for a Mars dust devil at

Phoenix was ~0.0289 mbar. Max drop at Pathfinder was .0477 mbar.

 Pressure drop for a 1953 dust devil that went directly

• ver a microbarograph was 1.354 mbar (13X greater

than Pathfinder event, 21X greater than Phoenix d. d.).

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SCALE HEIGHT

 The pressure acquired by a parcel of air moved up or

down a certain height at a constant temperature.

 By scale height math, pressure on Arsia Mons where

dust devils occur at 17 km should be about 1.17 mbar. Again, Ames couldn’t produce a dust devil @ 10 mbar. p = p0e-(h/h0) where

p = atmospheric pressure, h = height (altitude), P0 = pressure at height h = 0 (surface pressure), and H0 = scale height.

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Arsia Mons & other Martian Mountains, Valleys, Landers, and Methane Plumes.

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Spiral Clouds on Arsia Mons (only) look like Hurricane Eye Walls. 1.17 mbar seems too low.

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These clouds extend 15-30 km above the mountain, where scale height calculations indicate pressures of 0.29 to 0.07 mbar. This is like what’s seen for Earth at >34.9 km (>21 miles) above sea level.

NASA web site now does not post the same pressures as in 1970s. (http://nssdc.gsfc.nasa.gov/planetary/mars/mariner.html)

– Mariner 4 flyby: 4.5 to 9 mbar (old) or 4.1 to 7.0 mbar (new)

– Mariners 6 flyby and 7 flyby: 3.8 to 7.0 mbar (new). However

SP-4212 On Mars: Exploration of the Red Planet 1958-1978 (page 243) states of these flyby craft that the: “occultation experiment indicated that the atmospheric pressure at the surface of Mars ranged from 4 to 20 millibars, rather than 80 millibars as estimated earlier.”

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Occultation by Mariners missed high points (Olympus Mons) and low points (Hellas Basin).

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Mars Lander Pressure Sensors

 Only 4 landers could measure pressure in

situ.

 None could measure above 18 mbar

(and 2 were limited to 12 mbar).

 Limited pressure ranges

based on previous radio

• ccultation measurements.

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Viking & Pathfinder Pressure Sensitivity Ranges

 3 Tavis pressure sensors sent by NASA:

Viking 1 & 2 Range: 0 to 18 mbar

 Pathfinder: Only 0 to 12 mbar

A 1,034 mbar sensor was also ordered (Tavis CAD 10484 – 1 , but Tavis rep says it remained on Earth)

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5 to12 Mbar Range Phoenix Dust Filter

A Finnish Meteorological Institute report (2009)

States that, "We should find out how the pressure tube is mounted in the spacecraft and if there are additional filters etc.“ FMI designed the sensor.

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International Traffic in Arms Regulations

(ITAR)

 “After Phoenix landed it appeared that the

actual thermal environment was worse than the expected worse case… Information on re-location of the heat source had not been provided initially due to ITAR restrictions.” (Taylor, P.A., et al, 2009)

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“That we at FMI did not know how

• ur sensor was mounted in the spacecraft

and how many filters there were shows that the exchange of information between NASA and the foreign subcontractors did not work optimally in this mission!”

(Kahanpää [FMI] Personal communication, December 15, 2009)

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International Traffic in Arms Regulations (ITAR)

Data Too Similar Year to Year?

55% of same days each year for 4 years VL-1 Pressure was identical.

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PRESSURES DERIVED BY SPECTROMETER

Similar to VL-1; but

 don’t work with ice clouds and frost at

poles (Spiga et al., 2007).

 Pressure readings published for only 9 days

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COMPARISON OF MARS EXPRESS SPECTROSCOPY AND VIKING 1 PRESSURES

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Occam's Razor



(1) Entities must not be multiplied beyond necessity. (2) The simplest solution is usually the correct one.

 The Razor suggests that repeatable Viking

pressure data should be believed. However, the consistent Viking-Pathfinder-Phoenix pressures may only exist because they all had pressure sensor air access tubes clog in similar fashion .

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Why Trash Occam?

 OVERALL Viking pressures vary in inverse

proportion to ambient temperature and in direct proportion to heat required by RTGs to keep internal temperatures stable.

 Viking 1 Pressures for Year 1 are 98.19% in

agreement with predictions based on Gay- Lussac’s Law. This implies the transducer only measured internal, not external pressures.

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Why Trash Occam?

 Weather doesn’t match low pressure values

– Dust Devils – Dust Storms – Eye walls on huge storms over Arsia Mons

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Why Trash Occam?

 No way to change Viking, MPF and

Phoenix dust filters that could clog.

 Viking data suspicious due to exact repeat

• ver 4 yrs.

 Audit of Viking data shows huge patterns of

exactly the stuck pressures for up to 6 days (see Part 2 Presentation). Data shows no justification for continuing the pressure curves.

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WHY TRASH OCCUM? MRO AEROBRAKING

“At some points in the atmosphere, we saw a difference in the atmospheric density by a factor of 1.3, which means it was 30% higher than the model, but …

around the south pole we saw an even larger scale factor of up to 4.5, so that means it was 350% off of the Mars GRAM model.”

Han You, Navigation Team Chief for MRO.

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WHY TRASH OCCAM?

MGS Dynamic Pressure Spike @ 121 km Due to Dust Storms.

Pressure Doubles in 48 Hours, Up 5.6 Fold in 4 Weeks.

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Why Trash Occam?

 Pathfinder anemometers could not be calibrated.  Phoenix transducer design problems. ITAR at

• fault. Note: MSL/Curiosity’s 2011 Rover Environmental

Monitoring Station (REMS) will be built by the Spanish Ministry of Education with FMI still as a partner. FMI delivered the MSL pressure sensor to NASA in 2008 (before ITAR problems could be fixed)!

 No pressure sensors could measure > 18 mbar

(two could only go up to 12 mbar)

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Why Trash Occam?

 Landers with a 12 mbar max pressure capability

can’t handle a 6.6 mbar pressure increase due to dust storms like that at Luke AFB.

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Why Trash Occam?

 Diurnal pressure max of Viking & MPF

(midnight & 1000) don’t agree with Phoenix (0830 & 1530).

 Pressures almost always rose 0730

Local Time at VL-1 & 2. Probable cause? RTG heater.

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Cyclic nature of accurate prediction times showed a slow drift as seasons changed

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Why Trash Occam?

 NASA Ames failed to simulate dust devils

at 10 mbar with appropriate winds

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Where is the full report?

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Links to the most updated Basic Report and all Report Annexes are maintained at http://davidaroffman.com/catalog_1.html Annexes contain a full audit of Viking pressure data available at http://www- k12.atmos.washington.edu/k12/resources/mars_data- information/data.html.

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CONTACT INFO

 E-Mail: DavidARoffman@GMail.Com  Website: http://DavidARoffman.com

Slide References

 Slide 1: http://science.nasa.gov/science-news/science-at-

nasa/2001/ast11oct_2/

 Slide 2: 6.1 mbar from: Sherman, S.C. Wu (1977), Mars synthetic

topographic mapping, United States Geological Survey, Branch of Astrogeologic Studies, Flagstaff, Arizona 86001, USA

 Altitudes from http://www.csgnetwork.com/pressurealtcalc.html  MIG 25 view from http://www.digitalworldz.co.uk/225742-

joining-16-mile-high.html

 Slide 3:

http://www.lpl.arizona.edu/~lemmon/mer_dd/dd_enhanced_ 587a.gif

 Slide 4:

NASA, (2005). NASA simulates small Martian 'dust devils' and wind in vacuum tower. Retrieved from http://www.nasa.gov/centers/ames/research/exploringtheuniverse/vacc umchamber_prt.htm

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Slide References

 Slide 5: Reis, D., Lüsebrink, D., Hiesinger, H., Kel-ling, T., Wurm, G.,

and Teiser, J. (2009). High altitude dust devils on Arsia Mons, Mars: Testing the greenhouse and thermophoresis hypothesis of dust lifting. Lunar Planetary Science. [CD-ROM], XXXII, Abstract 2157. Retrieved from http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1961.pdf

 Slide 6: http://www.stevenhobbsphoto.com.au

and 2 mm MPF air tube from Seiff et al. (1997) The Atmospheric Structure and Meteorology instrument on the Mars Pathfinder Lander. http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/15328/Se iff%20et%20al%20JGR%201997.pdf?sequence=1

 Slide 7: Top and bottom graphs by Tillman and Johnson as found on

page 832 of MARS (1992) edited by Kieffer, H, Jakowsky, B, Snyder, C., and Matthews, M. Middle graph by David and Barry Roffman.

 Slide 8: Calculator from http://www.1728.com/gaspres.htm.

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Slide References

 Slide 9: Greeley, R; Lancaster, N; Lee, S. and Thomas, P. Martian Aeolian

Processes, Sediments, and Features (Chapter 12 of Mars [1992] edited by Kieffer, H.H. et al). Photo from: http://www.nasaimages.org/luna/servlet/detail/nasaNAS~5~5~ 23140~127274:First-Mars-Surface-Photo

 Slide 10: http://www.jpl.nasa.gov/news/news.cfm?release=2007-080.

Slide 11: http://www.nachi.org/forum/f11/awesome-phoenix-dust-storm- 62232/ Slide 12: Desai, P.N., (2008) All Recent Mars Landers Have Landed Downrange - Are Mars Atmosphere Models Mis-predicting Density? Third International Workshop on The Mars Atmosphere: Modeling and Observations, held November 10-13, 2008 in Williamsburg, Virginia. LPI Contribution No. 1447, p.9103. http://www.lpi.usra.edu/meetings/modeling2008/pdf/9103.pdf

 Slide 13:  Schofield, J.T. et al, (1997). The Mars Pathfinder atmospheric structure

investigation meteorology (ASI/MET experiment, Science, 278, 1752-1758

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Slide References

 Slides 13: Taylor, P. A., Catling, D. C., Daly, M., Dickinson, C. S.,.

Gunnlaugsson, H. P, Harri, A.M., and Lange C. F., (2008). Temperature, pressure, and wind instrumentation in the Phoenix meteorological package, Journal of Geophysical Research,113, E00A10.



http://www.nasa.gov/mission_pages/phoenix/images/press/16613- animated.html



and http://www.atm.ox.ac.uk/main/Science/posters2005/2005cw.pdf

 and http://mars.jpl.nasa.gov/MPF/mpf/sci_desc.html  Slides 14: Richardson, M., Wilson, R. J., and Rodin, A. V. Water ice

clouds in the Martian atmosphere: General circulation model experiments with a simple cloud scheme, J. Geophys. Res., 107(E9), 5064, doi:10.1029/2001JE0011804, 2002.

 Slide 15: Balme, M., Greeley R. (2006), Dust devils on Earth and Mars,

Review Geophysics., 44, RG3003,doi:10.1029/2005RG000188.

 Slide 16:  Balme, M., Greeley R. (2006), Dust devils on Earth and Mars, Review

Geophysics., 44, RG3003,doi:10.1029/2005RG000188.

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Slide References

 Slide 17: Balme, M., Greeley R. (2006), Dust devils on Earth and

Mars, Review Geophysics., 44, RG3003,doi:10.1029/2005RG000188.



Read, P. L., & Lewis, S. R. (2004). The Martian Climate Revisited, Atmosphere and Environment of a Desert Planet, Chichester, UK: Praxis. Slide 18: Balme, M., Greeley R. (2006), Dust devils on Earth and Mars, Review Geophysics., 44, RG3003,doi:10.1029/2005RG000188.

 Wyatt, R. E. (1954), Pressure Drop on a Dust Devil, Monthly

Weather Review, Jan. 1954, pp. 7-8. Retrieved from

 http://docs.lib.noaa.gov/rescue/mwr/082/mwr-082-01-0007.pdf

Slide 19: Photo from http://www.space4case.inhetweb.nl/mmw/media/mars20 05/tharsismontes9000_20051126_10_1024.jpg

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Slide References

 Slide 20: Calculations by David A Roffman based on

Smith, D. E., et al. (2001), Mars Orbiter Laser Altimeter: Experiment summary after the first year of global mapping of Mars, J. Geophys. Res., 106, 23,689–23,722, doi:10.1029/2000JE001364. http://www- geodyn.mit.edu/mola.summary.pdf

 Slide 21: NASA/JPL/MSSS, (2005). PIA04294: Repeated Clouds

• ver Arsia Mons. Retrieved from

http://photojournal.jpl.nasa.gov/catalog/PIA04294

 Slide 22:

http://nssdc.gsfc.nasa.gov/planetary/mars/mariner.html and http://history.nasa.gov/SP-4212/ch8.html

 Slide 23: Kliore, A.J. (1974), Radio occultation exploration of

Mars, Exploration of the planetary system; Proceedings of the Symposium, Torun, Poland, September 5-8, 1973. (A75-21276 08-91) Dordrecht, D. Reidel Publishing Co., 1974, p. 295-316.

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Slide References

 Slide 24: http://www/solarview.com  Slide 25: Personal communications and with a Tavis rep.  Slide 26: Kahanpaa, H., Polkko J., 2009-02-26. The Time

Response of the PHOENIX Pressure Sensor, Finnish Meteorological Institute. Doc. No. FMI_S-PHX-BAR-TN-002-FM- 99.

 Slide 27: Taylor, P.A., Weng, W., Kahanpää, H., Akingunola,

A., Cook, C., Daly, M., Dickinson, C., Harri, A., Hill, D., Hipkin, V., Polkko J., and Whiteway, J. (2009). On Pressure Measurement and Seasonal Pressure Variations at the Phoenix landing site, Submitted to Journal of Geophysical Research (Planets).

 Vailsala picture adapted from

http://www.space.fmi.fi/phoenix/?sivu=instrument.

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Slide References

 Slide 28: Personal communication with H. Kahanpää, FMI  Slide 29: J. E. Tillman, University of Washington, Dept.

Atmospheric Science

 Slide 30:  Remote sensing of surface pressure on Mars with the Mars

Express/OMEGA spectrometer: 1. Retrieval method

• A. Spiga, Forget, F., B. Dolla, S. Vinatier, R. Melchiorri, P.

Drossart, A. Gendrin, J.-P. Bibring, Y. Langevin, and B. Gondet (2007) Journal of Geophysical Research, 112, E08S15

 Slide 31: Remote sensing of surface pressure on Mars with the

Mars Express/OMEGA spectrometer: 1. Retrieval method Forget, F., A. Spiga, B. Dolla, S. Vinatier, R. Melchiorri, P. Drossart, A. Gendrin, J.-P. Bibring, Y. Langevin, and B. Gondet (2007) Journal of Geophysical Research, 112, E08S15

 J. E. Tillman, University of Washington, Dept. Atmospheric

Sciences

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Slide References

 Slide 35:

http://davidaroffman.com/VL2%20STUCK%20PRESSURE%20GAUGE%20639% 20to%20799.pdf.

 Slide 36: http://www.universetoday.com/2006/09/21/aerobraking-mars-

• rbiter-surprised-scientists/

 Slide 37: Johnston, M.D., Esposito, P. B., Alwar, V., Demcak, S. W., Graat,

• E. J., & Mase, R. A. of the Jet Propulsion Laboratory, California Institute of

Technology, Mars Global Surveyor Aerobraking at Mars, 1998

 Slide 38: http://www.atm.ox.ac.uk/main/Science/posters2005/2005cw.pdf

and

 http://starbrite.jpl.nasa.gov/pds/viewInstrumentProfile.jsp?INSTRUMENT_ID

=WINDSOCK&INSTRUMENT_HOST_ID=MPFL

 and http://en.wikipedia.org/wiki/Mars_Science_Laboratory  and http://space.fmi.fi/solar.htm  Slide 39: http://www.jpl.nasa.gov/news/news.cfm?release=2007-080.  And http://www.universetoday.com/2006/

http://www.universetoday.com/2006/

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Spare Slides If Needed

 Slide 43: http://oregonexplorer.info/craterlake/facts.html

and Water ice in Vastitas Borealis Crater (Credit: European Space Agency / ESA/DLR/FU Berlin (G. Neukum)) Slide 55: Calculations based on heights (except for Phoenix lander) given by David E. Smith et al. 2001

 Slide 56: Greeley, R; Lancaster, N; Lee, S. and Thomas, P. Martian

Aeolian Processes, Sediments, and Features (Chapter 12 of Mars [1992] edited by Kieffer, H.H. et al). Mars photo from http://lightsinthedark.wordpress.com/2011/01/26/beautiful- barchans/ Namibian and Moroccan dunes from http://www.bukisa.com/articles/44523_worlds-most-amazing-cliffs- and-fascinating-dunes Slide 57: http://www.atm.ox.ac.uk/main/Science/posters2005/2005cw.pdf

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SCALE HEIGHTS FOR MARTIAN MOUNTAINS AND VALLEYS

(Page 7 of Roffman Basic Report for HIGHER THAN ADVERTISED MARTIAN AIR PRESSURE)

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Why Trash Occam?

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Difficulty in explaining Barchan and other sand dune features, especially in craters on Mars if pressure is as low as advertised.

Pathfinder Pressure Uncertainties

 The (pressure) variation seen by Pathfinder …

The amplitude of the diurnal tide is sensitive to the calibration of the pressure sensor, which is still preliminary (Schofield, et al., 1997)

 May explain why the Pathfinder anemometers

could not be calibrated, however the wind socks were supposed to only move when winds topped 5 m/s. Cameras had to be working. The thermal wind sensor had other problems.

 Less than 12 wind measurements reported.

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