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-----------------------------1905 - Mars Explorations
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- “ExoMars is a satellite orbiting Mars since last month, October 2016. Much of the press has been about the lander, Schiaparelli, that had an altitude indicator malfunction and crashed on the surface. However, the satellite in orbit is still working fine.
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- The satellite is currently taking pictures in 3D and color from as low as 146 miles elevation. The resolution at this altitude is down to 20 meters across. The orbit is elliptical extending out to 62,000 miles completing its orbit every 4.2 days. The plan is to take 12 to 20 images of selected targets each day.
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- In addition to photos, the orbiting satellite carries 4 scientific instruments to measure methane, carbon dioxide, and evidence of water.
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- Detecting methane may provide evidence of some biological activity although it could also mean geological activity such as hydrothermal vents that can also produce methane.
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- One of the twenty successful missions to Mars has been the “Curiosity Rover” that has been exploring the surface of Mars for the last 4 years. Its most impressive discovery was uncovering evidence of warm, flowing water on the surface of Mars. The Rover must avoid these areas to prevent contamination. The areas are dark streaks that appear, fade, and re-appear. A total of 452 of these areas have been observed appearing in the warmest times of the year.
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- The water source is believed to be salt water that is frozen about a meter below the surface.
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- Curiosity Rover will avoid these areas as it climbs a mountainside to study sedimentary deposits. The goal is to learn from sediments how Mar’s environment has changed over the last 3 billion years. The geology of Mount Sharp has already shown evidence of a series of lakes along its basin.
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- The whole study must remain cautious because the Rover was only partially sterilized before launch and we do not know how long Earth microbes could survive in Mar’s atmosphere , or how far they could spread.
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- The next mission to Mars will be aimed at discovering Mar’s microbial life. It is imperative that these earlier missions do not contaminate this investigation.
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- There are currently 7 active missions studying Mars. The most recent arrival ExoMars 2016 will test for traces of methane in the atmosphere. The hope is to determine if the methane is from geological, chemical, or biological processes? ( See Footnote 1). This mission will also test for subsurface ice deposits.
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- May 2018 “ Insight Lander” is designed to study the density and structure of the core, mantle ,and crust of Mars.
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- In 2020 another Rover mission will collect and analyze soil for chemical signs of past life. It will use a plutonium-fueled nuclear radioactive thermal generator as a power source for an arm, camera, and seven other scientific instruments.
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- Several more missions from several nations are in the planning stage as well. This includes Elon Musk’s plans for a planned manned mission in 2025.
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- The mission would require a lot of material sent in advance of the crew. On year two the crew would launch taking 210 days to reach Mars. Spend 496 days on the planet and return taking another 210 days. The whole mission duration would take 6 years. It would cost more than $450 billion dollars, according to plan.
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- Footnote (1) - Methane as a gas gets broken down within 400 years by the effects of ultraviolet light. It must be replenished which could come from microbes which would be our first indication of life on Mars. But, a hot water reaction to the mineral olivine could be a source of methane. Also, the Sun’s ultraviolet rays breaking up micro-meteoroids on the dusty surface could produce methane. To tell the differences the ratios of carbon-13 and carbon-12 will be used.
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- Footnote (2) - Mars has 2 moons, Phobos, and Deimos. Deimos is 7.8 miles in diameter ( town size ). Phobos is 13.8 miles in diameter ( city size ). Deimos orbits at 14,580 miles elevation. Phobos orbits at a mere 5,827 miles above the surface taking only 7 hours and 39.2 minutes to complete each orbit.
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- The tidal forces and rotational stresses are pulling Phobos apart. Its self-gravity and tensile strength are holding it together. Its orbit is descending 2 centimeters per year. This inward spiral although small will lead to its destruction in 25 million years from now.
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- Phobos’ composition is porous , like a rubble pile. Its density is only 1.9 grams per cubic centimeter ( our Moon is 3.3 gm/cc). Like most meteorites its composition is carbonaceous chrondites, magnetite, olivine crystals, silicates and complex organic molecules, such as amino acids.
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- When Phobos reaches 3,400 miles above the surface it will completely disintegrate spreading into a ring circling Mars.
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- There several other reviews on Mars available upon request.
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----- 707-536-3272 ---------------- Saturday, December 3, 2016 -----
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