Use Mars Satellites Abstract Introduction

Home , Dust devil tracks, Noctis Labyrinthus

A GOOD WAY TO LEARN ABOUT MARS: USE MARS SATELLITES Jim Secosky email: [email protected] Website: Red Planet Trek: http://paws.flcc.edu/~secoskjj

ABSTRACT NASA has allowed amateurs to suggest areas to be imaged with Mars satellites. From 2003, until contact was lost in the fall of 2006, amateurs picked sites to be photographed with the Mars Global Surveyor (MGS) under the public target program. In 2007, elementary, high school, and college students from around the world started to direct NASA to places to focus on with the powerful HiRISE on the Mars Reconnaissance Orbiter. Jim Secosky, a retired science teacher and amateur user of HST, suggested thousands of places to explore with MGS's Mars Orbiter Camera (MOC). From the over 500 Jim received, he has put together a series of images that illustrate many geological features. Key Words: Mars Global Surveyor, Arabia, layers, gullies INTRODUCTION The Mars Global Surveyor was launched in 1996 and finished its mission in 2001. In August 2003, after receiving 120,000 images (about 3% of the surface), NASA started to allow amateurs to suggest areas to be imaged with the Mars Orbiter Camera (MOC). By the time contact was lost with the spacecraft in November 2006, over 250,000 images had been taken, 4,000 suggestions were made by amateurs and about 1,000 images under the public target program were received. MOC took content images and high resolution images of three sizes. The image footprint was approximately 1 or 2 miles wide and about 6, 11, or 26 miles long. Amateurs suggested places to look at that showed most of the major features of Mars including dust devil tracks, layers, buttes, canyons, volcanoes, patterned ground, sand dunes, gullies, and possible glacial features. OBSERVATIONS

Figure 1-MGS wide angle image showing ice cap and volcanoes. To give us some perspective, figure 1 shows some well-known major features. At the top is the northern ice cap. Olympus Mons, Alba Patera, Ascraeus Mons and Arsia Mons are the major 1 volcanoes on the Tharus Rise. Olympus Mons is three times higher than Earth's Mount Everest. Below Ascraeus Mons is a region of intersecting canyons knows as Noctis Labyrinthus or the labyrinth of the night. Just to its right or east the famous Valles Marineris begins.

Figure 2-- MOLA elevation map This brightly colored map was done with a laser on the MGS. White represents the highest altitude, while dark blue the lowest. The high spots are volcanoes. Besides the volcanoes of the Tharus Rise, another smaller group of volcanoes are found with Elysium Mons. The deepest area, Hellas, represents a large impact. The Valles Marineris is a deep canyon, probably caused by tectonic forces from the great load of the Tharus Rise volcanoes. The highland/lowland dichotomy shows as a large difference in elevation between the northern plains and the southern highlands. Besides displaying a boundary in elevations, it is a boundary in surface ages. The southern highlands for the most part show a high density of impact craters. The older a surface is the more craters it will have. The northern plains are smooth with few craters so they are thought to be young--Amazonian in age. The south is an old surface called Noachian in age. In between the two great time periods is the Hesperian, named for the region to the northeast of Hellas. This display of Mars is often used; it has zero degrees longitude at the far left with the other lines of longitude being so many degrees east. HiRISE and the Mars Express both use this system of longitude. To the right of Olympus Mons are three large volcanoes in a line. Pavonis Mons, the middle one, sits right on the equator, thereby providing an easy reference to the location of the equator. Notice how Arabia has an old surface with many craters, yet has a lower elevation than the heavily cratered southern highlands. It is an interesting place. I suggested many areas for MGS to image in this region. It seems to have layered formations scattered throughout. Layers can be formed from volcanic processes, wind, or even under water. I was interested in tracing possible lakes and seas from the past, since life may once have thrived there.

Figure 3 --map made by Malin Space Sciences using MOC on MGS This map with visible colors has zero degrees in the center. Longitude is sometimes measured west of this line. Syrtis Major is a very dark feature easily visible with backyard telescopes. Notice Arabia is quite some distance from the bulge of Olympus Mons. Some have suggested that Arabia was an old impact that was subsequently uplifted as an isostatic adjustment to the mass of Olympus Mons. Others have suggested that it was formed from a great impact that struck the northern region on an angle. Just to the north of Arabia lies Ismenius Lacus, an area having vast reaches of so-called frettered terrain. Two bands located 30-40 degrees north and south of the equator are where most gullies have been discovered. Gullies that are found on steep slopes may be caused by recent flows of liquid water.

Figure 4--Lee, Bell, Wolff photo showing Arabia up close Throughout Arabia layers of rock have been found. The infamous "Face of Mars" is found at the upper western edge of Arabia in an area called Cydonia.

Figure 5--The "Face" on Mars This feature looked just like a face in the Viking photos back in 1976. A more detailed view with the MGS showed it to be just an eroded plateau.

Figure 6--various views of image R19-01445 of the public target program. The image in the upper right was part of an image suggested by an amateur astronomer under the public target program. The R of the identification number denotes the mission phase. This image was number 01445 taken in month 19 of the R mission phase. The context image in the upper right contains a rectangle that shows the image footprint for the high resolution image. Other photos show parts of the high resolution blown up. Note the many layers. Some may be due to an ancient lake. The sequence for this formation would most likely be a large impact crater followed by the deposition of many layers in the crater and perhaps above it. Later erosion removed all but the small buttes in the center of the crater. In other words, these layers probably filled the entire crater. Recently, HiRISE imaged this general area and revealed many more layers (PSP_008520_2085).

Figure 7--images S21-00038 and S21-00037 from Malin Space Science Systems/NASA Inside a crater over 1,000 km away lays another butte that contains many layers similar to those of the previous picture. Again, these layers may have formed from lake or sea deposits. Since layers are seen so far away from each other the conditions for lakes may have been widespread in Arabia.

Figure 8--image S07-00496 from Malin Space Science/NASA About 1,000 km from the previous two sets of layers, this group of layers does not lie inside of a crater; rather it is between craters, so there was something about Arabia that caused layered deposits to form.

Figure 9--map of Arabia produced by U.S. Geological Survey. This map made from Viking photos shows the locations of the three sets of layered terrain. Extensive layered areas also are found in Henry and in craters just to the left of this frame. Also, of interest is the report of the detection of methane just to the left or west of the bottom. Methane has been reported from three locations on Mars. Methane should not last on Mars, so if these reports are validated, microbes may be producing the methane. The small, colored rectangles on the map represent image footprints for MGS high resolution photos. They are one or two miles in width and 6, 11, or 26 miles long. In the public target program one had to carefully avoid areas that had been photographed already. One had to have a very good reason to reimage a location. When I choose suggestions for the program, I often viewed the Viking maps in pieces 5 degrees square, looking for interesting features or things that looked different.

Figure 10--S02-00191, fretted terrain north of Arabia Just north of Arabia lays a vast region of fretted terrain, named for elongated features that resemble wrinkles. Fretted terrain contains large cliffs with wide, flat canyons. It is thought that as ice in the subsurface disappears by sublimation the material just crumbles. At the low Martian atmospheric pressures and temperatures ice does not melt; it just goes directly into a gas. The image footprint shows an attempt to view the cliff edge at high resolution.

Figure 11--cliff in S02-00190 This is a high resolution view of part of the cliff in the previous photo. Estimated at over one half mile high, this cliff would look amazing if you were standing at the base. Earth's Grand Canyon is just twice as tall this cliff. Maybe someday people will fly around cliffs like this on Mars, just as people fly over the Grand Canyon. 8

Figure 12--Phoenicis Lacus with Noctis Labyrinthus Just south of the equator sits a vast system of interlocking canyons called Noctis Labyrinthus. This view is on a Viking map. The high resolution view will be at the end of the arrow.

Figure 13--Noctis Labyrinthus with Pavonis Mons. Pavonis Mons marks the equator. Just to its south east is Noctis Labyrinthus in this image with MGS from Malin Space Science Systems/NASA.

Figure 14--S18-02389 with image rectangle I attempted to find layers or strata along the canyon wall in the location indicated with the rectangle. Any layers may have been formed by bodies of standing water in the past.

Figure 15--S18--02388 This shows the end of the rectangle in high resolution. Many layers are visible. The many volcanoes of Tharsus are off to the west so they may have formed some or all of the layers by a series of eruptions. This photo like others from MGS is credited to Malin Space Sciences/NASA.

Figure 16--S11-01674, gullies in crater On the upper (northern) wall of this crater, gullies are visible. Researchers first reported these features in 2000. They are believed to result from the movement of liquid water. Liquid water is needed for life to flourish.

Figure 17--S15--01135, apron covering sand dunes What was most exciting about gullies was that they are relatively young. The more craters on a surface, the older it is. Here the aprons from the gullies do not have any visible craters. The apron came after the sand dunes since the apron lies on top of the dunes. Notice the dunes themselves are also young because they do not have craters.

Figure 18--S14-01819, gullies showing alcoves channels, and aprons. Some gullies show alcoves and aprons with a connecting channel. It is thought that the area at the bottom of the alcove is undermined by liquid causing it to flow down, forming a winding channel, and ending up as an apron near the bottom of the slope. The winding nature of the channel indicates a rather slow speed of flow, therefore other ideas of formation can be eliminated. A landslide would form a straight channel. Likewise, liquid carbon dioxide would shoot out and travel much faster. Some gullies do not show all three features like this example does. At the bottom of some craters are ridges that may be a form of glacier.

Figure 19--S14-01118, gullies with possible glaciers This crater shows some gullies at the top and some ridges at the bottom. The tongue-shape forms at the bottom resemble terrestrial alpine glacier features, called terminal moraines. On Mars a glacier might flow for a while then instead of melting, like on Earth, it would disappear into the atmosphere as it sublimed from a solid to a gas phase. However, the rock and dirt it carried would pile up into ridges.

Figure 20--S05-00189 This set of images were quite exciting to me. I wanted to image this hill to see layers.

Figure 21--S05-00188 But when I looked at the high resolution view, there was a gully. This was the first gully I found! Gullies were one of the most important discoveries of the MGS. They may be one of the best places to find life and/or sources of water. We know that ice exists right beneath the surface at high latitudes, but these gullies are found much closer to the equator. When I obtained this image, I looked at the other gully images that Malin Space Sciences/NASA had released. There seemed to be only one other on a hill, so this one was a rare find. For sure, more recent studies have found a few more, but gullies on Martian hills are extremely infrequent. After examined this image, I wanted to image the scene again in higher resolution and to look for any changes.

Figure 22--S11-03165 In about 6 months, I received this image. You can see a little more detail, but there are no changes. NASA has reimaged hundreds of gullies in hopes of seeing some that are active. One was reported to have changed during the mission. A deposit of new material was seen during the years of the mission. However, later analysis showed that the new deposit could have just been a landslide because the slope was steep enough to have allowed the material to just move down by the force of gravity.

Figure 23--S20-00949, exhumed crater The MGS mission discovered that much of the surface of Mars contains features that have been exhumed from past ages. In this case at an earlier time, the surface was struck by a large meteorite, creating a crater with a central peak. Then the environment changed and great amounts of material buried the crater and the surface. Then, the material eroded away. At some point enough material was eroded away to reveal this crater from long, long ago.

Figure 24--S07-01520, dark spot on crater floor In this crater I was interested in discovering the nature of this dark matter on the crater floor. Notice how the image footprint straddles both the dark and light parts. I wondered if I could see a difference. 15

Figure 25--S07-01519, dark sand dunes The high resolution view revealed that dark dunes caused the dark spot.

Figure 26--S10-00778, dust devil tracks These dark lines are dust devil tracks. In many parts of Mars, giant dust devils remove a thin, bright-colored layer of dust from the underlying dark basalt. Every few months or so the patterns change.

Figure 27--light colored buttes against a black background Some parts of Mars have undergone major change. These light colored buttes are all that remain of a bright layer that once covered the entire region. The dark color is probably basalt from volcanoes. The light colored layer may be like the light colored material that Opportunity Rover examined. Opportunity found the material to contain sulfates probably formed with water.

CONCLUSION

Using MGS was very exciting, especially when some of the images contained possible evidence of past water. The public target program imaged many geological features common to Mars: sand dunes, craters, dust devil tracks, exhumed craters, layers (maybe formed under water), gullies, and possible glacial features. Images used in this talk are available at http://PAWS.flcc.edu/~secoskjj All images from the public target program can be viewed at http://www.msss.com. Information about using HiRISE can be found under public outreach at http://hirise.lpl.arizona.edu Using a satellite traveling around Mars is an excellent way to learn science, and it makes for a really fascinating project. Schools are desperate to improve science education. As members of the Mars Society, we can help kids with science projects using HiRISE and, in the process; help build widespread public support for human exploration of Mars. Some of us are teachers. Many of us could help neighbors, relatives, or a local teacher with such a project. The more kids get involved with Mars, the more they will want to explore it. At some point the HiRISE is supposed to be open for everyone to use--that's why from early on it was called the "people's camera." Soon we can all start to explore Mars!

ACKNOWLEDGEMENTS

The author is grateful for help from many people. All of his suggestions were submitted from public computers at libraries, hence, he wishes to thank the following libraries in New York: Red Jacket (Shortsville), Finger Lakes Community College (Canandaigua), Wood Library (Canandaigua), Clifton Springs Library, and Naples Library. He also wishes to thank the computer staff at Finger Lakes Community College for help assembling the images. Nearly all images are products of Malin Space Science Systems/NASA. Other images were from MOLA Science Team/GSFC/NASA, U.S. Geological Survey, and the team of Steve Lee, Jim Bell, Mike Wolff, and NASA

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