The Face of Mars

8/8/2019 The Face of Mars

1/35

U

0

'z~m

ro4

IQ

~

U-aO

>2

:

I~

Q

I2

=3Ory

?

ry

~

~U>

L

U

ZU

I

wn

Ea? a

-Z

*

0

1

.CZ

I

pAL

0

o

O

o

Y

Eo0

=

0

C1

0

g

V

'-0

0o

o

o 0e

I0^2

C

14 o

C-

c

7

U34

~

Q)

:

ac

tg

4

0N

IPr


2/35

. . . man 's past in space is but aprologue in his insatiable

search for knowledge ofhis environment."

W. H. Pickering

Pasadena Star News, January 1, 1972

Sketch showing the comparison in size of the Martian volcanic mountain. Nix Olympica, with California.


3/35

ir -troduics -tiora

Th is do cum ent provides a brief

summary of salient science resultsobtained from the M ariner 9 m issionthrough early June 1972. Mariner 9, thefourth U.S.A. spacecraft to make thejourney to Mars and the first to orbit theplanet, represents the latest in the evolvingfamily of Mariner spacecraft.

The previous missions to Mars, made in1965 and 1969 by Mariners 4, 6, and 7 ,were flyby missions and provided only abrief glimpse of the planet. Although theirviews of Mars were more limited, themissions were invaluable because theysupplied man with the first close look atMars and formed the basis for theMariner 9 technology. In turn, the datafrom M ariner 9 will provide inform ationand technological experience from whichthe Viking 1975 Project will benefit.Therefo re, the success of M ariner 9 willalso be reflected in the Viking orbiter

spacecraft, which will transport the Vikinginstrumented capsules to Mars for theirlanding on the planet's surface in 1976.

Details (this doc;

studied (


4/35


5/35

3

.

o

:

o

,

-C

S

C

a

3

^

C

o

3O

_

'

coC

0

S-

.

grC

v

-o

S

o

B

PC.(-O

C

c

c

8

3

30

O

B

CD

~'

~:

~

~o

'~

'

-

'

"

'

*

-C

>*-

^*.

'.

;

-

VT-

K-

,mnm\iFf 5 0 km

Figure 6. (aJ Crater complex of Nix Olympic(c) South Spot crater, (d j Middle Spot.


11/35

(b)

^y Crater complex of North Spot. Figure 7. Views of the south polar cap.


12/35

scale. Mariner 9 pictures displaying the gradualdisappearance of the residual polar cap areshown in Figure 8. The s outh pole is locatedjust off the residual cap area (about the centerof the cap and just above the cap in theNovember 18 picture ). Investigations haveshown that the areas are smooth, and the linesare terraces, or changes in elevation, betweenthe smooth, terraced terrain. The entire cap inthe November 18 pictures covers about a 10arc on the Martian surface. (This was reducedto about an 8 arc by December 24.)

Mariner 9 obtained the first close-up viewsof the Martian satellites, Phobos and Deimos.Both satellites are heavily cratered, indicating aprobable age of several billion years. They aretwo of the darkest objects in our solar systemever to be photographed. Phobos has an albedo(reflective power) of about 5 percent, andDeimos about 6 percent.

Phobos the closer satellite, is about 25 kilometers (16 miles) long and about 21 kilometers (12 miles) wide. An especially strikingfeature is the 5.3-kilometer (3.3-mile) craternear the bottom (south pole) in Figure 9a andnear the center in Figure 9b. The impact thatproduced the crater is close to the largestimpact Phobos could have sustained without

fracture and disruption. Many of the irregularedges on Phobos may have been produced bythe breaking off of pieces on impact. Deimos,the farther satellite, is about 13-1/2 kilometers(8-1/2 miles) long and about 12 kilometers(7-1/2 m iles) wide. Two clear crater-like depressions, each about 1-1/2 kilometers (1 mile)across, are apparent in Figure 10 near theterminator (region of shading that separates theday from the night side of the satellite). Thedeep cleft at the bottom is probably a valleyabout \Y tkilometers deep.

NOVEMBER 18

10

DECEMBER 13

Figure 8. Four early views of the south polar cap taken overa 36-day period.


13/35

Figure 10. Computer-processed picture ofDeimos obtained at a distance of8830 kilometers (5487 miles).

Figure 9. Computer-processed pictures of Phobos. (a) View obtained at a distanceof 14,440 kilometers (8973 miles), (b) View obtained at a distance of 5550 kilometers (3449 miles).


14/35

-

C~~~.

C

CD

CD

C

lw,CD

CD

C0

C :5

C

D

0

-q

-5e

0n

o

Op

5S

-

CD

c

,CD c

o

C

0

"C

O

0 ,D

*

C

0

e

0

CD

0C

-

kC

(D

C

0

5

:>

o

5

-

X

-0 0

40

.

o

oW CD

>

0

0

0,

0 W

v

(C

CD

p

,

CD

CD

0

0

go

C

fD

0

'

X

CW

0O.

>

C

D

,

4

>

.

W

CD

CD

C

C

C

0

-

-~

'0

w

-

CD

CD

-

CrO

0

~~~~~,0

0

"

0C~

D

CD

0D

~

0

C

4CD

CZ

0

~CD

~

CD

r~

CDCD

CD

W

C

P

C

CD

0

0

0

E

CD

C

D

L

EL

C

D

o-

C

-

C

C

0~~~

,

0

~CD 0

CD

-

-

Cr"

-'0

C

-D

C

o

50

M

C

C

C0

0

-0

C

D

i

tW @

Y8

~

o0

,+ . -1

CD

3

~o

CDo

i

I0R

N;0;Z Q

a

:>

_

z;0

ZID

0 0

H

O0

8

2 ,I >

2

0

1,

00

0O

,

10

20

3

O _O O0

2

m a

C0 x

C

P

WC

0o

CD

0

o 5w

OD

AL

ITUDE,

km

0 o 0 Z .M -


15/35

A

SN

N

O

_~

o

IO.~Oc

.0

8

S-t

,U ~

E

'

L

ap_

z~

.-Q

'8~

gD

LIzS

.3

a

X

A

SN

N

o

U

t

I

S

s~

a

s

S

>oo

.

g

JLXPoJ

s_-

M DN\1N]Ia

3DNV3:33i

*


16/35

T

MPERATURE,

O

_~

_

o

-

-_

ITM

U

F

I

IT

MPERATURE,

0F

0

-

OC D0

oBCO

0

o

=o

C

o

o-~

00

o

0

0

-

0

o

A

+

-o

O0

(D >

PXC4

-

g

-o

C

0 0 -4

=w

3

0D

W

Z

-0

w

5

A

)

o

oC

2

C

_

t

.

C

CD

C

D

'

0

B

C

:5.

c

~~~~~~~~

0~

o-~L

~~

D


19/35

%\

L

Jmt"

"

t*'

*

.

1

nt

~T

'

."


20/35

mulations of ground ice or may be deflatedhollows developed by wind action in looselyconsolidated material. A complex pattern ofdelicate swirls and blotches, which cloak thesouth polar region, is shown in Figure 22. Thearea covered in the picture is about 80 by100 kilometers (50 by 62 miles) and is locatedat about 80 south latitude.

The first clear view of rilles (cracks) in theMartian crust was obtained on January 7 inMare Sirenum (see Figure 23). These structuresare part of a system of parallel fissures extending more than 1800 kilometers (1100 miles)along the surface. Lunar rilles have been interpreted as tensional features produced bystretching of the upper rock layers. The sameorigin seems probable for the Martian rilles.

The Martian canyonlands, part of a120,000-square-kilometer (46,300-square-mile)complex in Noctis Lacus on the northern edgeof the Solis Lacus region, also were photographed by Mariner 9. The canyons, about 10to 20 kilomete rs (6 to 12 miles) wide , havesmooth floors and are separated from oneanother by flat-surfaced plateaus. The Martiancanyons may be as deep as 6 kilometers(4 miles), and the walls slope 10 to 15 degrees.Their overall dimensions are similar to those ofthe Grand Canyon in Arizona. The linearsegments of the canyon walls are roughlyparallel to one another. Observations suggestthat the canyons are of structural origin, butthe intricate fluting of the walls indicateserosional modification. An intricate network ofcanyons is shown in Figure 24. The picture,

which covers an area 542 kilometers wide by426 kilometers high (336 by 264 miles), showsevidence of the erosion processes.

The clearer atmosphere revealed NixOlympica as a mountain 500 kilometers(310 miles) wide at th e base (see Figure 25) .Steep cliffs drop off from the mountain flanksto a surrounding great plain. The main crater atthe summit, a complex multiple volcanic vent,is 65 kilometers (40 miles) wide. The mountainis more than twice as broad as the most massivevolcanic pile on Earth. The mountain thatforms the Hawaiian Islands is 225 kilometers(140 miles) across and rises 9 kilometers(6 miles) from the floor of the Pacific to thesummit crater, Mauna Loa.

Figure 22. Picture showing complex pattern of swirls and blotches. Dark splotchesat low er left, right center, and bottom center are on the floors of surfacedepressions.

Figure 23. Rilles in the Martian crust. The widestrille, at upper left, is about 1-1/2kilometers (1 m ile) across and contains a more sha llow rille in its floor. Thediagonal rille across the center of the picture is about 40 kilometers (25 miles) long.


21/35

Figure 25. C omputer-processed picture of Nix O lympica photographed byMariner 9 in late January 1972.

Figure 24. Network of Martian canyons.

N H N . \

1 9


22/35

Toward the end of the mapping mission,features of special interest were studied such asthe braided channel sweeping past a crater19 kilometers (12 miles) wide (see Figure 26) .This channel suggests the former presence offluid erosion of the Martian surface. However,the meandering "river" (see Figure 27), thoughnot unique on the Martian surface, is the mostconvincing evidence that a fluid once flowedalong the surface, draining an extended areaand eroding a deep channel. Landforms arebeing studied in detail to determine whetherwater or some other fluid system was the activeagent. Light and dark streaks, which usuallyoriginate at small topographic features such ascraters and bumps, were observed over widelyseparated regions of the Martian surface (seeFigure 28). Elongated patches of similar albedo

are roughly parallel within a region, suggestingthat their formation is related to erosion and/ordeposition by Martian winds.

With the dust subsiding, the ultravioletspectrometer was able to penetrate to thesurface. Using the physical process calledRayleigh sc attering, the topograph y of Marswas examined, providing a third dimension ofinformation (height) to the television pictures.Comparison of pressure measurements made bythe ultraviolet spectrometer with a mosaic oftwo pictures of the Tithonius Lacus region onMars revealed a vast canyon four times as deepas Earth's Grand Canyon (see Figure 29). TheMartian canyon is estimated from ultravioletsp ec tro me ter data to be 6 kilometers(19,7 00 feet, or a bout 3-3/4 m iles) deep and120 kilometers (75 miles) wide. (Earth's GrandCanyon is 1.7 kilometers (5500 feet) deep and21 kilometers (13 miles) wide. The vast chasmsand branching canyons represent landform evolution apparently unique to Mars. Subsidence

along lines of weakness in the crust andsculpturing by winds are believed to haveformed the features.

Figure 26. Two-picture mo saic showing braided channel sweeping past acrater. Both pictures were taken from an average range of ab out1800 kilometers (1116 miles).


23/35

Figure 27. This meandering "river", about 575 kilometers (355 miles) longand 5 to 6 kilometers (3 to 3-1/2 miles) wide,resembles a giant version of anEarth "arroyo" . .. a watercut gully found frequently in the mountainoussouthwestern United States. The feature extends from 3 8 to 45 westlongitude and 27 to 30 south latitude.


24/35

IS3

INJ

Spectra from the ultraviolet spectrometer carbon monoxide, and ionized molecular


25/35

Figure 30. Clouds of a type notuncommon on Earth on the lee sideof m ountains. The only surfacedetail visible here is a frost-rimmedcrater about 90 kilometers(56 m iles) wide. T he flow of airover the crater rims produces wave

clouds that propagate for severalhundred kilometers.

showed that the atmosphere is composed primarily of carbon dioxide with small amounts ofcarbon monoxide, oxygen, and a few otherminor constituents that result from the photochemistry of a carbon dioxide atmosphere witha small amount of water.

Measurements performed in the upper atmo

sphere of Mars (above 100 kilometers) show thepresence of atomic hydrogen, atomic oxygen,and carbon monoxide as the neutral species; theionosphere contains ionized carbon dioxide,

oxygen. The amount of ionization is variablewith location and time above the planet andmay depend upon the Sun's radiation input tothe upper atmosphere of Mars. The atomichydrogen signal observed by the ultravioletspectrometer also varies with time and location.Correlation of the Mars atomic hydrogenLyman alpha signal (1216 angstroms) with

observations of the influence of the Sun on theEarth's atmosphere shows that the atmosphereof Mars is responding primarily to solar photonradiation rather than the solar wind. This is

:: \ J ? z : .

'if- ' : fe w:

f

V

tr t

*


26/35

Figure 31. Thick wave clouds viewed by Mariner 9. (a)Wave formation in the twilight lighting, (b) The same featureobserved the next day as a silhouette on the limb of the planet.

24

determined by observing the time lag betweenthe response of Earth's atmosphere to thevariable solar flux when compared with theMartian atmosphere.

The loss of atomic hydrogen from the planetalso was measured by the ultraviolet spectrometer. If the source of the hydrogen were fromwater, the loss would be equivalent to2-1 /2centimeters (1 inch) of rain over an area about9-1/2 meters (30 feet) wide and about 1-1/2 kil

ometers (1 mile) long, or about 100,000 gallonsof water per day. This is not as alarming as itseems; this quantity of water could have beenlost from Mars each day since the planet wasfirst created and still would represent less than1 percent of its total available water.

One of the observations made by Mariner 7in 1969 was that there appeared to be ozone onor above the south polar cap. However, noconfirm ation of the presence of ozone was

observed by Mariner 9. After December 30,when observations of the north polar regionwere possible (above 40 north latitude), theabsorption spectrum of ozone was observedeverywhere in the north polar hood. During thissame time period, observations of the southpolar area continued to show no presence ofozone until the change of the Martian season.With the southern hemisphere entering the

Martian fall in March 1972, the ultravioletspectrometer observed an increase in reflected


27/35

0 . 0 3

0 . 0 5

1 0 . 0

n 1 1 1 r n 1 1 1 1 r

REVOLUTION 5( -38 ,283)

R E V O L U T I O N 11 4( - 1 6 , 3 0 8 )

200 210 220 230 240 250

TEMPERATURE, K

Figure 32. Atmospheric changes observed on 3 successive days. The circle in theFebruary 12 picture indicates the location of the crater visible in the February 13 and 14pictures and shows the apparent perturbations emphasized by the cloud pattern.

Figure 33. Representative Martian atmospheric temperature profiles,

going from isothermal to almost adiabatic. Profiles were obtainedfrom infrared interferometer spectrometer data on November 16,December 14, and January 9.

light near the south polar cap. This has beeninterpreted as the onset of a south polar haze.Associated with this haze was the presence ofthe ozone absorption spectrum. With theapproach of winter in the southern hemisphere,the ozone concentration in the south hascontinued to increase.

An unanticipated "bonus" derived from themission was the observation of young stars inthe ultraviolet portion of the spectrum. Mea

surements of these stars cannot be made fromEarth because the Earth's atmosphere absorbsthe ultraviolet part of the spectrum. Theobservations will supply information about theevolution of these stars . . . whether or not theyhave gas clouds about them, and whether theyare in regions of space in which large amountsof galactic dust exist.

Throu ghout the Mariner 9 mission, Mars hasbeen experiencing winter in its northern hemi

sphere. During this season, latitudes above about45 north have been blanketed by clouds suchas shown in Figure 30. A patch of thick cloudsobserved at 54.8 north latitude is shown inFigure 31a; these same clouds were viewed thenext day silhouetted on the limb of the planet(Figure 31b). Pictures of the same region showing atmospheric changes on successive days are

shown in Figure 32. Data from the infraredinstrum ents indicate that the cloud deck is consistent with that of condensed carbon dioxide. 25

CC

5iO

< ~ - oC 5C C 3=


28/35

o r/

-o

0a

5

0

-

a~O>

0O

0

0

0

0

0

s

-

CD

C

'1

0

3

p

0

D

,CD

C

-*

4C

3C

CD

CD

eD ~

0

4 * 3

? ff 438 O 442

STANDARD 90 -DAY MISSION ENTRIES STANDARD 90 -DA Y MISSION EX ITS O SECOND SET DATA ENTRIES(PROVISIONAL) * SECOND SET DATA EXITS (PROVISIONAL)

SOUTH

0 X 0 o0CD

. 0 W )J o 0-' W o 0 0 E- PO :Lc


32/35

DISTANCE

FROM CENT

R OF MA

km

5

0

0

.

0

~

'~

0B

:oCW

0

-

1

~0

n

.0 .

,X

w

C

w

C

-C

CC '0

)0

0

)

-

B

D

~0

~

"

Z~~

~CD

cnC

0

D

-x

Mcn

o

"

:3

'~

~

~D

=.

~

=

C

.-~~~~

?>

CD5~~l


35/35

'-

0

0

0

v

0

C DX

H

.

a

(

Bw

go,

0~

-

e

,

_

o

X

-0 0

Documents

The Face of Mars