Mars ExplorationExam ResultsAverage = 66Median = 68Highest = 94Lowest = 25ABCDEMars• Distance from the Sun =1.524 that of Earth• Diameter = 53% Earth• Gravity = 38% of Earth• Atmospheric pressure =0.6% that of EarthMars in Popular Culture• God of War (Ares-Greeks, Mars-Romans)• Perceval Lowell thinks that he see canalsand argues that there must be people• Science Fiction Martians, e.g. War of theWorlds, by H. G. Wells and many, manyothersPerceval Lowelllooking at Mars athis observatory inFlagstaff, AZLowell’s drawings of MartiancanalsFrom the start, science fictionwriters such as H. G. Wellswere fascinated by Mars.On October 30, 1938, a radioplay by Orson Welles, basedon the book, fooled thousandsinto thinking that Martianswere attacking Earth.History of Mars Spacecraft Explorationhttp://mars.jpl.nasa.gov/missions/log/How is a Mission Chosen?• Someone (a committee of respected scientists, theNASA administrator, a politician) decides onbroad science goals.• Teams of scientists and spacecraft engineers writea proposal describing the mission including thespacecraft, science instruments, and observationsto be made.• Another committee is formed to review theproposals and pick the “best” one.• The spacecraft is built and launched, data obtainedand analyzed, and results are communicated to therest of the world.Science Goals for the MarsProgram• Determine whether Life ever arose onMars• Characterize the Climate of Mars• Characterize the Geology of Mars• Prepare for Human Exploration1. Search for and characterize a variety of rocks and soils that hold clues to pastwater activity. In particular, samples sought will include those that haveminerals deposited by water-related processes such as precipitation,evaporation, sedimentary cementation, or hydrothermal activity.2. Determine the distribution and composition of minerals, rocks, and soilssurrounding the landing sites.3. Determine what geologic processes have shaped the local terrain andinfluenced the chemistry. Such processes could include water or wind erosion,sedimentation, hydrothermal mechanisms, volcanism, and cratering.4. Perform "ground truth" -- calibration and validation -- of surface observationsmade by Mars orbiter instruments. This will help determine the accuracy andeffectiveness of various instruments that survey Martian geology from orbit.5. Search for iron-containing minerals, identify and quantify relative amounts ofspecific mineral types that contain water or were formed in water, such asiron-bearing carbonates.6. Characterize the mineralogy and textures of rocks and soils and determine theprocesses that created them.7. Search for geological clues to the environmental conditions that existed whenliquid water was present. Assess whether those environments were conduciveto life.Science Goals for the Rover MissionsMariner 4 Image of Martian SurfaceMariner 7 Images of MarsMariner 9 arrives atMars in the midst of aplanet-wide dust storm.All that can be seen on thesurface are some diffuseround spots. What arethese? Will the dust stormend in time?Finally, the storm lessensand the dust begins toclear…Mariner 9 image of Mars duringthe big dust stormEureka! We can see the surface, but what is this?False color image of OylmpusMonsMariner 9 reveals the firstvolcanoes on another solarsystem body.Terrestrial ShieldVolcanoOlympus Mons: The Solar System’sLargest MountainOlympus Mons is about 26 km (16 miles) high and covers an area the size ofArizona. It is a shield volcano, like the volcanoes in Hawaii. Notice thecaldera at the top.Shield Volcanoes are mountains built up by lava. The lava has low viscosity (runs easily), so shieldvolcanoes are large with shallow slopesFamous Shield VolcanoesMauna Kea, HawaiiMt Fuji, JapanViking Missions to MarsFirst spacecraft to land on another planet (we’dalready landed on the moon).Goals were:• search for microbial life on Mars.• Characterized the surface and atmosphere• Obtain high resolution images of the surfaceOrganic Molecules. To a chemist organic only meanscontaining carbon. There is no implication orassociation with life. Planetary scientist use the wordin this sense. Thus, if a planetary scientist says thatthere are organic molecules on Mars, she only meansthat the molecules contain carbon.News media often (almost always) get this confused.Nevertheless, Viking carried a mass spectrometerdesigned to search for organic molecules, in thehope that discovery of large organic moleculeswould indicate the presence of life. No significantabundance of organic molecules was found.Problems with life on Mars1. No liquid water. It’s much drier and colder thananywhere on Earth.2. No ozone layer. The UV radiation from the Sun isintense on the surface of Mars. This would breakapart any large organic molecules before theyformed.3. Soil is highly oxidized. It’s very difficult to build uplarge molecules in an oxidizing environment. Lifedeveloped on Earth before there was significantoxygen in the atmosphere.4. People, scientists included, still hope…There’s lots of water (H2O) onMars, it’s just in the form of ice orwater vapor. Liquid water cannotexist at the temperatures andpressures on Mars.Upper left: Maritan polar caps, composed ofCO2 and H2O ice.Lower left: close-up of north polar cap.Lower right: Frost on the Martian surface.Ancient River Beds?What does this look like to you? An ancient river system perhaps?More Images of Possible Ancient River BedsFrom Hartmann and ImpeyEvidence for Water?A series of troughs and layered mesas inthe Gorgonum Chaos region of themartian southern hemisphere appears inthe chaotic terrain. Gullies proposed tohave been formed by seeping groundwater emanate from a specific layer nearthe tops of trough walls, particularly onsouth-facing slopes. Such a layer iscalled an aquifer, and this one appearsto be present less than a few hundredmeters (few hundred yards) beneath thesurface in this region. This image wastaken by the Mars Global Surveyorcamera on January 22, 2000.Islands in the StreamThe teardrop shape is characteristic of water flowing past an obstacle.Ancient Sediments?Water on Mars?Mars can not have liquid water at the currenttemperature and pressure of its atmosphere, yetthere are numerous forms on the surface thatappear to have been caused by the flow of water.This is one of the main questions facing planetaryscientists today. To support water, Mars musthave a much thicker atmospheres. Was
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