MarsPHYS 178 – 2008 Week 4, Part 2

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Lowell’s Mars Globe

One of the remarkable globes of Mars prepared by

Percival Lowell, showing a network of dozens of canals,

oases, and triangular water reservoirs that he claimedwere visible on the red planet. (Lowell Observatory)

2 Table 9-1, p.199

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Mars - HST This NASA Hubble SpaceTelescope view of the planet Mars is the

clearest picture ever taken from Earth. The

picture was taken on February 25, 1995,

when Mars was at a distance of 100 millionkm from Earth. Because it is spring in Mars'

northern hemisphere, much of the carbon

dioxide frost around the permanent water-icecap has sublimated, and the cap has receded

to a core of solid water-ice several hundred

miles across.

Towering 25 km above the surrounding

plains, volcano Ascraeus Mons pokes above

the cloud deck near the western or limb. Thisextinct volcano, measuring 402 km across,

was discovered in the early 1970s by Mariner

9 spacecraft. Other key geologic featuresinclude (lower left) the Valles Marineris, an

immense rift valley the length of the

continental United States. Near the center ofthe disk lies the Chryse basin made up of

cratered and chaotic terrain.

The oval-looking Argyre impact basin(bottom), appears white due to clouds or

frost. Seasonal winds carry dust to form

striking linear features reminiscent of thelegendary martian "canals." Many of these

"wind streaks" emanate from the bowl of

these craters where dark coarse sand isswept out by winds. Dark areas, once

misinterpreted as regions of vegetation by

several early Mars watchers, are areas ofcoarse sand that is less reflective than the

finer, lighter dust. Seasonal changes in the

surface appearance occur as winds move thedust and sand around.

4

Mars - Happy Face Crater

The story of the Mars Orbiter Camera (MOC) onboard the

Mars Global Surveyor (MGS) spacecraft began with a

proposal to NASA in 1985. The first MOC flew on Mars

Observer, a spacecraft that was lost before it reached thered planet in 1993. Now, after 14 years of effort, a MOC

has finally been placed in the desired mapping orbit. The

MOC team's happiness is perhaps best expressed by theplanet Mars itself. On the first day of the Mapping Phase

of the MGS mission--during the second week of March

1999--MOC was greeted with this view of "Happy FaceCrater" (center right) smiling back at the camera from its

location on the east side of Argyre Planitia. This crater is

officially known as Galle Crater, and it is about 215kilometers (134 miles) across. The picture was taken by

the MOC's red and blue wide angle cameras. The bluish-

white tone is caused by wintertime frost. Illumination isfrom the upper left.

5 Fig 9-13, p.206

Mars Globe from Radar These globes are highly precise topographic maps, reconstructed from

millions of individual elevation measurements with the Mars Global Surveyor spacecraft. Color is usedto indicate elevation. The hemisphere on the left includes Olympus Mons, the highest mountain on

Mars, while the hemisphere on the right includes the Hellas basin, which has the lowest elevation on

Mars. (JPL/NASA)

6

Regional Topographic Views of Mars fromMOLA

With one year of global mapping of the MarsGlobal Surveyor mission completed, the

MOLA dataset has achieved excellent spatial

and vertical resolution. This map has been

produced from the altimetric observationscollected during MOLA's first year of global

mapping and provide a variety of regional

topographic views of the Martian surface.The maps were compiled from a data base of

266.7 million laser altimetric measurements

collected between March 1, 1999 andFebruary 29, 2000. In each map the spatial

resolution is approximately 1/16° by 1/32°

(where 1° on Mars is about 59 km) and thevertical accuracy is approximately 1 meter.

PIA01049

7Olympus Mons - Altimetry

8 Fig 9-14, p.206

Olympus Mons The largest volcano on Mars, and probably in the solar system in a rendering based

on data from the Mars Orbiter Laser Altimeter. The caldera, the circular opening at the top, is 65 km

across, about the size of Los Angeles. Note the extensive clouds over the lower slopes of the volcano.(Kees Veenenbos)

9

Elysium Chasm - Altimetry

Comparison of the cross-sectional relief of the deepest portion of the Grand Canyon (Arizona) on Earth versus a Mars

Orbiter Laser Altimeter (MOLA) view of a common type of chasm on Mars in the western Elysium region. The Grand

Canyon topography is shown as a trace with a measurement every 90 m along track, while that from MOLA reflectsmeasurements about every 400 m along track. The slopes of the steep inner canyon wall of the Martian feature exceed

the angle of repose, suggesting relative youth and the potential for landslides. The inner wall slopes of the Grand Canyon

are less than those of the Martian chasm, reflecting the long period of erosion necessary to form its mile-deep characteron Earth.

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Valles Marineris

This high resolution picture (right) of the Martian surface was obtained by the Mars Orbiter Camera (MOC). Seen in this view are aplateau and surrounding steep slopes within the Valles Marineris, the large system of canyons that stretches 4000 km along the

equator of Mars. The image covers only 9.8 km by 17.3 km but captures features as small as 6 m across. The highest terrain in the

image is the relatively smooth plateau near the center. Slopes descend to the north and south in broad, debris-filled gullies withintervening rocky spurs. Multiple rock layers, varying from a few to a few tens of meters thick, are visible in the steep slopes on the

spurs and gullies. Layered rocks on Earth form from sedimentary processes and volcanic processes. Both origins are possible for

the Martian layered rocks seen in this image. In either case, the total thickness of the layered rocks seen in this image implies acomplex and extremely active early history for geologic processes on Mars. The left and center 'context' images are Viking mosaics.

11 Fig 9-15, p.207

Martian Landslides

This Viking orbiter image shows one section of the Valles Marineris canyon system. The canyon walls are about 100

km apart here. Look carefully and you can see enormous landslides whose debris is piled up underneath the cliff walls,which tower some 10 km above the canyon floor. (NASA/USGS)

12Fig 9CO,

p.194

Heavily Eroded Canyonlands on Mars This Viking spacecraft view looks down

on a small part of the Valles Marineris canyon complex and shows an area about60 km across(NASA/USGS, courtesy of Alfred McEwen)

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Geologic 'Face on Mars'Formation

NASA's Viking 1 Orbiterspacecraft photographed

this region in the northern

latitudes of Mars on July25, 1976 while searching

for a landing site for the

Viking 2 Lander. Thespeckled appearance of the

image is due to missing

data, called bit errors,

caused by problems intransmission of the

photographic data from

Mars to Earth. Bit errorscomprise part of one of the

'eyes' and 'nostrils' on the

eroded rock that resemblesa human face near the

center of the image.

Shadows in the rockformation give the illusion

of a nose and mouth.

Planetary geologistsattribute the origin of the

formation to purely natural

processes. The feature is

1.5 kilometers across, withthe sun angle at

approximately 20 degrees.

The picture was taken froma range of 1,873

kilometers.

PIA01141

14 p.215

The “Face on Mars” isseen here with ten times

better resolution from

Global Surveyor. The

image has beenprocessed to simulate

the lighting conditions of

the Viking image foreasier comparison.

(NASA/Malin SpaceScience Systems)

15

Teardrop Islands

The water that carved the channels to the north andeast of the Valles Marineris canyon system had

tremendous erosive power. One consequence of

this erosion was the formation of streamlined islandswhere the water encountered obstacles along its

path. This image shows two streamlined islands that

formed as the water was diverted by two 8-10-kilometer-diameter craters lying near the mouth of

Ares Vallis in Chryse Planitia. The water flowed from

south to north (bottom to top of image). Note that theejecta blanket of the third large crater (located at the

tapered downstream tail of the uppermost island) is

uneroded, an indication that this crater formedsometime after the channel was active. The height

of the scarp surrounding the upper island is about

400 meters, while the scarp surrounding thesouthern island is about 600 meters high. (From

Mars Digital Image Map, image processing by Brian

Fessler, Lunar and Planetary Institute.)

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Flow around Dromore Crater,

Chryse Planitia, Mars

Viking 1 Orbiter image ofDromore Crater in Chryse

Planitia, Mars. Flow from the left

(west) appears to have brokenthrough low points on the ridge

and eroded the channels as it

flowed around the 15 kmdiameter crater. The image is

approximately 50 km across.

North is at about 1:30. (VikingOrbiter 020A62)

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Yuty - Rampart Crater withFluidized Ejecta (22°N,34°W)

The ejecta deposits around theimpact crater Yuty (18 km in

diameter) consist of many

overlapping lobes. Craters withthis type of ejecta deposit are

known as rampart craters. This

type of ejecta morphology ischaracteristic of many craters

at equatorial and midlatitudes

on Mars but is unlike that seen

around small craters on theMoon. This style of ejecta

deposit is believed to form

when an impacting objectrapidly melts ice in the

subsurface. The presence of

liquid water in the ejectedmaterial allows it to flow along

the surface, giving the ejecta

blanket its characteristic,fluidized appearance. (Viking

Orbiter image 3A07.)

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Parana Valles

drainage system

in MargaritiferSinus, Mars

This Viking 1Orbiter image

shows the Parana

Valles, a digitatevalley network in

the Margaritifer

Sinus region ofMars. These

networks look

similar to river

drainage networkson Earth, and

were presumably

formed by runningwater sometime in

Mars' past. This

image is about250 km across.

North is at ~10:30.

(Viking Orbiter084A47)

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Mars - Chaotic Terrain

Like many other channels that empty into the northern plains of Mars, Ravi Vallis originates in a region of collapsed anddisrupted ("chaotic") terrain within the planet's older, cratered highlands. Structures in these channels indicate that they were

carved by liquid water moving at high flow rates. The abrupt beginning of the channel, with no apparent tributaries, suggests

that the water that carved the channel was released under great pressure from beneath a confining layer of frozen ground. Asthis water was released and flowed away, the overlying surface collapsed, producing the disruption and subsidence shown

here. Three such regions of chaotic collapsed material are seen in this image, connected by a channel whose floor was

scoured by the flowing water. The flow in this channel was from west to east (left to right). This channel ultimately links up witha system of channels that flowed northward into Chryse Basin. (Image processing by Brian Fessler, LPI)

20 Fig 9-23, p.212

Evidence of Liquid Water on MarsThis intriguing channel, called Nanedi Valles resembles

Earth river beds in some (but not all) ways. The tight curves

and terraces seen in the channel certainly suggest thesustained flow of a fluid like water. The channel is about 2.5

km across and the entire Global Surveyor image is 10 km

wide. (NASA/Malin Space Science Systems)

21 Fig 9-24, p.213

Outflow Channels

Here we see a region of large outflow

channels, photographed by Viking.These features appear to have been

formed in the distant past from massive

floods of water. The width of this image

is about 150 km. (NASA/JPL)

22 Fig 9-22, p.212

Runoff Channels These runoff channels in the old martian highlands are interpreted as the valleys of

ancient rivers fed either by rain or underground springs. The width of this image is about 200km.(NASA/from Mars Digital Image Map, processing by Brian Fessler, LPI)

23 Fig 9-25b, p.213

Recent Gullies on MarsGullies on the wall of

Newton Crater. Each

image is about 2 kmacross.

(NASA/JPL/USGS)

24 Fig 9-26, p.213

Stratification in the

Martian Crust

As many as 100layers can be seen in

this high-resolution

photo of a wind-eroded mesa within

the Valles Marineris

canyons. Manygeologists interpret

this photo as

evidence for layers ofsediment deposited in

an ancient martian

sea. The width of theimage is only 1.5 km.

(NASA/JPL/USGS)

25 Fig 9-25a, p.213

Recent Gullies on

MarsGullies on a cliff near

the South Polar Cap.

(NASA/JPL/USGS)

26 Fig 9-19, p.209

Sand Dunes on Mars

These dark dunes in the interior of ProctorCrater overlay a lighter sandy surface. Each

dune in this high-resolution view is about 1 km

across. (NASA/JPL/USGS)

27 Fig 9-18, p.209

Tracks of Dust Devils

This high-resolution

photo from MarsGlobal Surveyor shows

the dark tracks of

several dust devils thathave stripped away a

thin coating of light-

colored dust. This viewis of an area about 3

km across. Dust devils

are one of the most

important ways thatdust gets redistributed

by the martian winds.

(NASA/JPL/USGS)

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Mars - North Polar Cap

These images were created

by assembling mosaics of

three sets of images takenby HST in October, 1996

and in January and March,

1997 and projecting them toappear as they would if seen

from above the pole. The

resulting polar maps beginat 50 degrees N latitude and

are oriented with 0 degrees

longitude at the 12 o'clock

position. This series ofpictures captures the

seasonal retreat of Mars'

north polar cap. October1996 (early spring in the

Northern hemisphere): In

this map, assembled fromimages obtained between

Oct. 8 and 15, the cap

extends down to 60 degreesN latitude, nearly it's

maximum winter extent. A

thin, comma- shaped cloudof dust can be seen as a

salmon-colored crescent at

the 7 o'clock position. Thecap is actually fairly circular

about the pole at this

season; the bluish "knobs"

where the cap seems toextend further are clouds

that occurred near the edges

of the sets of images used tomake the mosaic.

29 Fig 9-21, p.211

Layers at the Martian North Pole

The small inset in the left image shows a map of the residual north polar cap of Mars, which is about 1000 kmacross and composed of water ice. The small black box in the middle of the map shows the area covered in the

tilted Viking orbiter image at left. The box in that image shows the area of the Global Surveyor high-resolution

image at right. On the right image, we see a slope on the edge of the permanent north polar cap, with dozens of

layers visible—some thinner than 10 meters. (NASA/JPL/Malin Space Science Systems)

30 Fig 9-20, p.210

Martian Meteorite

A fragment of basalt ejectedfrom Mars in a crater-forming

impact, that eventually arrived

on the Earth’s surface.

(NASA/JSC)

31 Fig 9-16a, p.208

Three Martian Landing Sites The Mars landers -- Viking 1 in Chryse, Viking 2 in Utopia, and Pathfinder in Ares Valley --

all photographed their immediate surroundings. It is apparent from the similarity of these three photos that each spacecraft toucheddown on a flat windswept plain littered with rocks ranging from tiny pebbles up to meter-size boulders. It is probable that most of

Mars looks like this on the surface. (NASA/JPL/USGS)

32 Fig 9-16b, p.208

Viking 2 in Utopia

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Sojourner on Pathfinder

The Sojourner rover and undeployed ramps onboard the Mars Pathfinder spacecraft can be seen in in this image, by the Imagerfor Mars Pathfinder (IMP) on July 4 (Sol 1). This image has been corrected for the curvature created by parallax. The microrover

Sojourner is latched to the petal, and has not yet been deployed. The ramps are a pair of deployable metal reels which will provide

a track for the rover as it slowly rolls off the lander, over the spacecraft's deflated airbags, and onto the surface of Mars. Pathfinderscientists will use this image to determine whether it is safe to deploy the ramps. One or both of the ramps will be unfurled, and

then scientists will decide whether the rover will use either the forward or backward ramp for its descent.

34

Sojourner at Yogi In this scene showing the rover deployed at rock Yogi, the colors have been enhanced to bring out

differences. Yogi (red arrow), one of the large rocks with a weathered coating, exhibits a fresh face to the northeast,

resulting perhaps from scouring or from fracturing off of pieces to expose a fresher surface. Barnacle Bill and Cradle (bluearrows) are typical of the unweathered smaller rocks. During its traverse to Yogi the rover stirred the soil and exposed

material from several cm in depth. During one of the turns to deploy Sojourner's Alpha Proton X-Ray Spectrometer (inset

and white arrow), the wheels dug particularly deeply and exposed white material. The lander's rear ramp, which Sojournerused to descend to the Martian surface, is at lower left.

35

D-Star Panorama by Opportunity

NASA's twin Mars Exploration Rovers have been getting smarter as they get older. This view from Opportunity shows thetracks left by a drive executed with more onboard autonomy than has been used on any other drive by a Mars rover.

Opportunity made the curving, 15.8-meter (52-foot) drive during its 1,160th Martian day, or sol (April 29, 2007). It was testing

a navigational capability called "Field D-star," which enables the rover to plan optimal long-range drives around anyobstacles in order to travel the most direct safe route to the drive's designated destination. Field D-Star and several other

upgrades were part of new onboard software uploaded from Earth in 2006. Victoria Crater is in the background, at the top of

the image. The Sol 1,160 drive began at the place near the center of the image where tracks overlap each other. Tracksfarther away were left by earlier drives nearer to the northern rim of the crater. For scale, the distance between the parallel

tracks left by the rover's wheels is about 1 m from the middle of one track to the middle of the other. The rocks in the center

foreground are roughly 7 to 10 cm tall. The rover could actually drive over them easily, but for this test, settings in theonboard hazard-detection software were adjusted to make these smaller rocks be considered dangerous to the rover. The

patch of larger rocks to the right was set as a keep-out zone. The location from which this image was taken is where the

rover stopped driving to communicate with Earth. A straight line from the starting point to the destination would be 11 m.Opportunity plotted and followed a smoothly curved, efficient path around the rocks, always keeping the rover in safe areas.

NASA/JPL-Caltech/Cornell University PIA10213

36

Phoenix Mission Lander on Mars, Artist's Concept

The Phoenix Mission is the first project in NASA's openly competed program of Mars Scout missions. The mission's plan

is to land in icy soils near the north polar permanent ice cap of Mars and explore the history of the water in these soils and

any associated rocks, while monitoring polar climate. The spacecraft and its instruments are designed to analyze samplescollected from up to a half-meter deep by a robotic arm. The arm extends forward in this artist's concept of the lander on

Mars. (NASA/JPL )

PIA07247

37

'Snow White' Trench

This image was acquired by

NASA's Phoenix MarsLander's Surface Stereo

Imager on Sol the 43rd Martian

day after landing (July 8,

2008). This image shows thetrench informally called "Snow

White."

Two samples were delivered to

the Wet Chemistry Laboratory,

which is part of Phoenix'sMicroscopy, Electrochemistry,

and Conductivity Analyzer

(MECA). The first sample was

taken from the surface areajust left of the trench and

informally named "Rosy Red."

It was delivered to the WetChemistry Laboratory on Sol

30 (June 25, 2008). The

second sample, informallynamed "Sorceress," was taken

from the center of the "Snow

White" trench and delivered tothe Wet Chemistry Laboratory

on Sol 41 (July 6, 2008).

NASA/JPL-Caltech/University of

Arizona/Texas A&M University

PIA11010:

38

Color View of 'Rosy Red' Delivered to TEGANASA's Phoenix Mars Lander's Surface Stereo Imager took this false color

image on Sol 72 (August 7, 2008), the 72nd Martian day after landing. It

shows a soil sample from a trench informally called "Rosy Red" after beingdelivered to a gap between partially opened doors on the lander's Thermal

and Evolved-Gas Analyzer, or TEGA.

NASA/JPL-Caltech/University of Arizona/Texas A&M UniversityPIA11023

39

40 Table 9-2, p.203

41 The New Solar System ch13

42 The New Solar System ch13

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