Rendered images of surface details on Mars
About these images
Fortunately, I finally got my hands on a more detailed (1/45 degree,
i.e. 1.3 arc minutes) color map of Mars without a shadow
and obtained the 1/128 degree topography data (i.e. less than
30 arc seconds, that is 0.22 square kilometers around the
equator). As this map does not cover the poles, the 1/64 degree
map was used to fill up latitude ranges 88-90°, North and South.
Unfortunately, all this information sums up to a total of 2400Mb
which poses some trouble in handling.
Hence, I wrote a patch for POVRay which allows me to only read
parts of image maps into memory. An example scene applying this
technique while setting up the rendering of a some landing site can
be seen on the right (the red cylinder marks the planned viewport center;
height scale factor is 40).
Furthermore, most images here were rendered with my
isosurface accuracy patch applied to POVRay-3.5.
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What one can see
Mars actually has a very thin atmosphere (6.5hPa, i.e. less than
1/100th that of Earth), consisting mostly of CO2 (carbon
dioxide, 95%).
After looking at some real images from NASA's space robots, I chose to
give Mars an atmosphere similar to the one in the
Earth renders with
scattering and a density gradient.
The visible part of it is about 30km thick.
The size and strength of the atmosphere is exaggerated for artistic reasons.
The images were taken from quite low above the surface (normally
500 to 1000km) which is still much higher than a space shuttle travels
around Earth (which is just about 300 to 400km over ground).
I normally applied strong light often coming in a very flat angle to
achieve sharp shadows and improved visibility of surface details.
Note that unless stated otherwise,
the topography in the below images is natural height.
Mars robot landing sites
It is well-known that quite a lot of robots were sent to Mars in order
to do some research (as looking for signs of life, etc.). Unfortunately,
too many of them failed...
As I was interested on how the landing sites look like, I decided to
have a closer look.
510km altitude looking North, natural height
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Spirit landing site
In Jan 4, 2004, NASA's Mars rover Spirit landed on the
red planet. NASA chose a location at 14.59°S, 175.30°E (IAU 2000),
which is right in the center of the large crater which can be seen in
the left image (about 25% from top; MOLA elevation -1910m).
Especially note the large (dry) river bed which seems to flow into
the crater.
Applying my image slice patch, memory consumption was kept down to about
100Mb while using the highest resolutions available (1/128° topo,
1/45° color).
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680km altitude looking NNW, natural height
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Beagle2 landing site
In Dec 26, 2003, a ESA's (European Space Agency) first Mars robot,
Beagle2 (an allusion to Charles Darwin's travel on the ship "Beagle"),
landed on the red planet.
ESA chose a location at 10°-12°N, 86°-94°E for their robot,
centered at 11.6°N, 90.5°E which is just in the upper thirs of the left
image (right in middle of the "boring" flat sand with few craters).
This region is called Isidis Planitia and has a MOLA elevation
of -3600m to -3900m.
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680km altitude looking WNW, natural height
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Opportunity landing site
In Jan 25, 2004, NASA's Mars rover Opportunity landed on Mars.
The landing site is located at 1.98°S, 354.06°E (IAU 2000) and
has a MOLA elevation of -1910m.
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Other interesting sites
680km altitude looking ESE, natural height
680km altitude looking ESE, natural height
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Some other interesting site
This is some interesting site I came across while looking at the Mars
topography. Looks like a (dry) river is connecting some craters flowing
from right back to right front and then to the left into some larger
lake or ocean. Also note the dark patches which look like sediments from
flowing water.
As we're at computer graphics here anyway, why not try how it would
look when we put some water there? Well, see yourself on the second
image. The water surface is at about -2600m (MOLA elevation)
with slightly increasing altitude as we move to the right.
So, what about "terra forming" on Mars? Better forget it: Solar wind is
constantly blowing away the atmosphere of the red planet. Long time ago,
Mars had much more atmosphere but the solar wind has blown it away,
especially the light gases.
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Mountains
There are 4 really large mountains on Mars which were once volcanos but
seem to be inactive today.
While tracing these images with POVRay-3.5, I notized strange black
dots on some parts of the images. One day, I decided to investigate
the problem and finally wrote an
accuracy improvement patch
for POVRay, which eliminated the disorion.
The images below were traced with my patch applied, of course.
Olympus Mons: 850km altitude looking SE, natural height
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Olympus Mons
Of course, we may not miss Olympus Mons which is said to be
the highest volcano in the solar system: it is 24km high and measures
550km across. The large scrap around the volcano is 6km high.
To compare it: Mauna Loa, the largest volcano on Earth, is 9km high
and measures 120km in horizontal extent.
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Ascraeus Mons: 510km altitude looking NW, natural height
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Pavonis Mons: 510km altitude looking NW, natural height
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Arsia Mons: 510km altitude looking NW, natural height
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Shield Volcanos
In the Tharsis Montes region, there are three shield volcanos
lined up in NE direction called (north-to-south) Ascraeus Mons,
Pavonis Mons and Arsia Mons. These volcanos
measure 350km to 450km across and their tops are about 15km above
the surrounding plains.
On the left there is an image of the middle one.
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Vallis Marineris
There is a gigantic canyon system on Mars, called Vallis Marineris.
It extends over 4000km and is up to 7km deep. To compare:
Grand Canyon, the largest canyon on Earth, is 350km long, up to
1.8km deep and measures 6 to 29km across.
While Grand Canyon in NW-Arizona (USA) was created by water
erosion of the Colorado River, several theories exist for
Vallis Marineris: One is that the huge scrap was caused by
another planet(oid) flying very near by slightly touching the surface
of Mars.
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Flying along Vallis Marineris
This is a little animation of a flight along Vallis Marineris,
a large canyon on Mars. It is available on the
film page.
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