The North Pole - Mare Boreum Region
This Region covers all of the Martian surface north of latitude 65°. It includes the north polar ice cap, which has a swirl pattern and is roughly 1,100 km across. Mariner 9 in 1972 discovered a belt of sand dunes that ring the polar ice deposits, which is 500 km across in some places and may be the largest dune field in the solar system. The ice cap is surrounded by the vast plains of Planum Boreum and Vastitas Borealis. Close to the pole, there is a large valley, Chasma Boreale, that may have been formed from water melting from the ice cap. An alternative view is that it was made by winds coming off the cold pole. Another prominent feature is a smooth rise, called Olympia Planitia. In the summer, a dark collar around the residual cap becomes visible; it is mostly caused by dunes.
Spring –Summer Ice on North Pole
The Region includes some very large craters that stand out in the north because the area is smooth with little change in topography. These large craters are Lomonosov and Korolev. Although smaller, the crater Stokes is also prominent.
The ground of the Planum Boreum mixed with ice and sand.
Planum Boreum (Latin: "the northern plain") is the northern polar plain on Mars. It extends northward from roughly 80°N. Surrounding the high polar plain is a flat and featureless lowland plain called Vastitas Borealis which extends for approximately 1500 kilometers southwards, dominating the northern hemisphere.
Viking mosaic Mare Boreum and surrounding areas southward
The planet Mars has two permanent polar ice caps. During a pole's winter, it lies in continuous darkness, chilling the surface and causing the deposition of 25–30% of the atmosphere into slabs of CO2 ice (dry ice). When the poles are again exposed to sunlight, the frozen CO2 sublimes, creating enormous winds that sweep off the poles as fast as 400 km/h. These seasonal actions transport large amounts of dust and water vapor, giving rise to Earth-like frost and large cirrus clouds. Clouds of water-ice were photographed by the Opportunity rover in 2004. The caps at both poles consist primarily of water ice. Frozen carbon dioxide accumulates as a comparatively thin layer about one meter thick on the north cap in the northern winter only, while the south cap has a permanent dry ice cover about 8 m thick.
Early speculation about life on Mars: The Mars' polar ice caps were observed as early as the mid-17th century, and they were first proven to grow and shrink alternately, in the summer and winter of each hemisphere, by William Herschel in the latter part of the 18th century. By the mid-19th century, astronomers knew that Mars had certain other similarities to Earth, for example that the length of a day on Mars was almost the same as a day on Earth. They also knew that its axial tilt was similar to Earth's, which meant it experienced seasons just as Earth does — but of nearly double the length owing to its much longer year. These observations led to the increase in speculation that the darker albedo features were water, and brighter ones were land. Spectroscopic analysis of Mars' atmosphere began in earnest in 1894, when U.S. astronomer William Wallace Campbell showed that neither water nor oxygen were present in the Martian atmosphere. By 1909 better telescopes and the best perihelic opposition of Mars since 1877 conclusively put an end to the canal theory, it was therefore natural to suppose that Mars may be inhabited by some form of life.
The Vastitas Borealis: (Latin, 'northern waste' ) is the largest lowland region of Mars. It is in the northerly latitudes of the planet and encircles the northern polar region. Vastitas Borealis is often simply referred to as the northern plains or northern lowlands of Mars. The plains lie 4–5 km below the mean radius of the planet. To the north lies Planum Boreum. The region was named by Eugene Antoniadi, who noted the distinct albedo feature of the Northern plains in his book La Planète Mars (1930). The name was officially adopted by the International Astronomical Union in 1973.
Terrain in the Vastitas Borealis\
Two distinct basins are recognized within the Vastitas Borealis: the North Polar Basin and Utopia Planitia. Some scientists have speculated the plains were covered by an ocean at some point in Mars' history and putative shorelines have been suggested for its southern edges. Today these mildly sloping plains are marked by ridges, low hills, and sparse cratering. Vastitas Borealis is noticeably smoother than similar topographical areas in the south.
Surface of Mars, as seen by Phoenix (spacecraft). The ground is shaped into polygons which are common where the ground freezes and thaws in the North Pole Region.
Dunes and Layers
Lomonosov Crater: is a medium sized crater on Mars, with a diameter close to 150 km. It is located in the Martian northern plains north of the planet's equator. Since it is large and found close (65.9° north) to the boundary between the and the Mare Boreum Region and the , Mare Acidalium Region and is found on both maps. The topography is smooth and young in this area, hence Lomonosov is easy to spot on large maps of Mars.
Rim of Lomonosov Crater
Korolev Crater is a crater in the Mare Boreum Region of Mars, located at 73° north latitude and 195.5° west longitude. It is 84.2 km in diameter and was named after Sergey Pavlovich Korolev (1906-1966), the head Soviet rocket engineer and designer.
Edge of ice mound in the center of Korolev Crater
Stokes Crater: is an impact crater on Mars. It is located on the Martian Northern plains. It is distinctive for its dark-toned sand dunes, which have been formed by the planet's strong winds. It was named after George Gabriel Stokes. Research released in July 2010 showed that it is one of at least nine craters in the northern lowlands that contains hydrated minerals. They are clay minerals, also called phyllosilicates.
Possible Phyllosilicate-rich terrain in Stokes Crater
The Chasma Boreale: is a large canyon in Mars's north polar ice cap in the Mare Boreum Region of Mars at 83° north latitude and 47.1° west longitude. It is about 560 km (350 mi) long and was named after a classical albedo feature name. The canyon's sides reveal layered features within the ice cap that result from seasonal melting and deposition of ice, together with dust deposits from Martian dust storms.
Terrain in the central part of the Chasma Boreale
Information about the past climate of Mars may eventually be revealed in these layers, just as tree ring patterns and ice core data do on Earth. Both polar caps also display grooved features, probably caused by wind flow patterns. The grooves are also influenced by the amount of dust. The more dust, the darker the surface. The darker the surface, the more melting as dark surfaces absorb more energy.
Computer-generated view based on images of Chasma Boreale captured by the THEMIS instrument on Mars Odyssey.
The Phoenix Lander: was a robotic spacecraft on a space exploration mission on Mars under the Mars Scout Program. The Phoenix lander descended on Mars on May 25, 2008. Mission scientists used instruments aboard the lander to search for environments suitable for microbial life on Mars, and to research the history of water there. The Phoenix lander landed on Vastitas Borealis within the Mare Boreum Region at 68.218830° N and 234.250778° E on May 25, 2008. The probe collected and analyzed soil samples in an effort to detect water and determine how hospitable the planet might once have been for life to grow. It remained active there until winter conditions became too harsh around five months later.
Location of Phoenix Lander
Water on Mars exists almost exists exclusively as water ice, located in the Martian polar ice caps and under the shallow Martian surface even at more temperate latitudes. A small amount of water vapor is present in the atmosphere. There are no bodies of liquid water on the Martian surface because its atmospheric pressure at the surface averages 600 pascals (0.087 psi) —about 0.6% of Earth's mean sea level pressure— and because the temperature is far too low, (210 K (−63 °C)) leads to immediate freezing. Despite this, about 3.8 billion years ago, there was a denser atmosphere, higher temperature, and vast amounts of liquid water flowed on the surface, including large oceans. It has been estimated that the primordial oceans on Mars would have covered between 36% and 75% of the planet.
Artist Concept of Phoenix Lander
Phoenix was NASA's sixth successful landing out of seven attempts and was the first successful landing in a Martian polar region. The lander completed its mission in August 2008, and made a last brief communication with Earth on November 2 as available solar power dropped with the Martian winter. The mission was declared concluded on November 10, 2008, after engineers were unable to re-contact the craft.
The mission had two goals. One was to study the geologic history of water, the key to unlocking the story of past climate change. The second was evaluate past or potential planetary habitability in the ice-soil boundary. Phoenix's instruments were suitable for uncovering information on the geological and possibly biological history of the Martian Arctic. Phoenix was the first mission to return data from either of the poles, and contributed to NASA's main strategy for Mars exploration, "Follow the water." Phoenix landed in the Green Valley of Vastitas Borealis on May 25, 2008, in the late Martian northern hemisphere spring , where the Sun shone on its solar panels the whole Martian day. By the Martian northern Summer solstice (June 25, 2008), the Sun appeared at its maximum elevation of 47.0 degrees. Phoenix experienced its first sunset at the start of September 2008. The polygonal cracking in this area had previously been observed from orbit, and is similar to patterns seen in permafrost areas in polar and high altitude regions of Earth. A likely formation mechanism is that permafrost ice contracts when the temperature decreases, creating a polygonal pattern of cracks, which are then filled by loose soil falling in from above. When the temperature increases and the ice expands back to its former volume, it thus cannot assume its former shape, but is forced to buckle upwards. The Lander's Robotic Arm touched soil on the red planet for the first time on May 31, 2008 (sol 6). It scooped dirt and started sampling the Martian soil for ice after days of testing. Phoenix's Robotic Arm Camera took an image underneath the lander on sol 5 that shows patches of a smooth bright surface uncovered when thruster exhaust blew off overlying loose soil. It was later shown to be ice. On June 19, 2008 (sol 24), NASA announced that dice-sized clumps of bright material in the "Dodo-Goldilocks" trench dug by the robotic arm had vaporized over the course of four days, strongly implying that they were composed of water ice which sublimated following exposure.
Color versions of the photos showing ice sublimation, with the lower left corner of the trench enlarged in the insets in the upper right of the images.
On June 24, 2008 (sol 29), NASA's scientists launched a major series of tests. The robotic arm scooped up more soil and delivered it to 3 different on-board analyzers: an oven that baked it and tested the emitted gases, a microscopic imager, and a wet chemistry lab. The lander's Robotic Arm scoop was positioned over the Wet Chemistry Lab delivery funnel on Sol 29 (the 29th Martian day after landing, i.e. June 24, 2008). The soil was transferred to the instrument on sol 30 (June 25, 2008), and Phoenix performed the first wet chemistry tests. Preliminary wet chemistry lab results showed the surface soil is moderately alkaline, between pH 8 and 9. Magnesium, sodium, potassium and chloride ions were found; the overall level of salinity was modest. Chloride levels were low, and thus the bulk of the anions present were not initially identified. The pH and salinity level were viewed as benign from the standpoint of biology. TEGA analysis of its first soil sample indicated the presence of bound water and CO2 that were released during the final (highest-temperature, 1,000°C) heating cycle
Weather: Snow was observed to fall from cirrus clouds. The clouds formed at a level in the atmosphere that was around −65 degrees C, so the clouds would have to be composed of water-ice, rather than carbon dioxide-ice (dry ice) because, at the low pressure of the Martian atmosphere, the temperature for forming carbon dioxide ice is much lower—less than −120 degrees C. As a result of the mission, it is now believed that water ice (snow) would have accumulated later in the year at this location. This represents a milestone in understanding Martian weather. Wind speeds ranged from 11 to 58 km per hour. The usual average speed was 36 km per hour. These speeds seem high, but the atmosphere of Mars is very thin—less than 1% of the Earth's—and so did not exert much force on the spacecraft. The highest temperature measured during the mission was −19.6°C, while the coldest was −97.7°C.
Polar regions: Mars' north and south poles once attracted great interest as settlement sites because seasonally-varying polar ice caps have long been observed by telescope from Earth. Mars Odyssey found the largest concentration of water near the north pole, but also showed that water likely exists in lower latitudes as well, making the poles less compelling as a settlement locale. Like Earth, Mars sees a midnight sun at the poles during local summer and polar night during local winter.
It has been suggested that Mars once had an environment relatively similar to that of Earth during an earlier stage in its development. While water appears to have once existed on the Martian surface, it now only appears to exist at the poles and just below the planetary surface as permafrost. The lack of both a magnetic field and geologic activity on Mars may be a result of its relatively small size, which allowed the interior to cool more quickly than Earth's, though the details of such a process are still not well understood. The soil and atmosphere of Mars contain many of the main elements needed for life. Large amounts of water ice exist below the Martian surface, as well as on the surface at the poles, where it is mixed with dry ice, frozen CO2. Significant amounts of water are stored in the south pole of Mars, which, if melted, would correspond to a planet wide ocean 11 meters deep. Frozen carbon dioxide (CO2) at the poles sublimates into the atmosphere during the Martian summers, and small amounts of water residue are left behind, which fast winds sweep off the poles at speeds approaching 250 mph (400 km/h). This seasonal occurrence transports large amounts of dust and water vapor into the atmosphere, giving potential for Earth-like cirrus clouds. Most of the oxygen in the Martian atmosphere is present as carbon dioxide (CO2), the main atmospheric component. Molecular oxygen (O2) only exists in trace amounts. Large amounts of elemental oxygen can be also found in metal oxides on the Martian surface, and in the soil, in the form of per-nitrates. An analysis of soil samples taken by the Phoenix lander indicated the presence of perchlorate, which has been used to liberate oxygen in chemical oxygen generators. Electrolysis could be employed to separate water on the planet into oxygen and hydrogen if sufficient liquid water and electricity were available.