Mission to Mars: Project Based Learning Benchmark Lessons Dr. Anthony Petrosino, Department of Curriculum and Instruction, College of Education, University of Texas at Austin Benchmarks content author: Elisabeth Ambrose, Department of Astronomy, University of Texas at Austin Project funded by the Center for Instructional Technologies, University of Texas at Austin http://www.edb.utexas.edu/missiontomars/bench/bench.html Table of Contents Mars as a Solar System Body 4 Place in the Solar System 4 Physical Properties and Composition 5 The Moons of Mars 7 Mars geography 8 Mountains 10 Volcanoes 10 Valleys 11 Craters 12 Surface Rocks 14 Crust Composition 16 Atmosphere composition 17 Ice caps 17 Conditions on Mars 18 Gravity 18 Atmosphere 18 Weather, winds, storms 19 Temperatures, seasons, climate 20 Length of year 22 Length of day 22 Water on Mars 22 2 Polar Ice Caps 22 Water channels 23 Surface Water 25 Previous, Current, and Future Missions to Mars 25 Mariner 4 25 Mariner 6-7 26 Mariner 9 26 Viking 1-2 27 Mars Pathfinder/Sojurner Rover 27 Mars Global Surveyor 28 2001 Mars Odyssey 29 2003 Mars Exploration Rovers 29 2005 Mars Reconnaissance Orbiter 30 Smart Lander and Long-Range Rover 30 Scout Missions 31 Sample Return and Other Missions 31 Getting to Mars 31 Escape velocity 31 Routes and travel time 33 Supplies: food, water, oxygen 35 Psychological needs/concerns 35 References 40 3 Mars as a Solar System Body Place in the Solar System Sun and planets. NASA/JPL. This picture depicts the four gas The Solar System. NASA/JPL. giant planets (Jupiter, Saturn, Uranus, This picture depicts the correct and Neptune), Earth, and the Sun. Earth relative sizes of the 9 planets of the Solar is the tiny dot between Jupiter and the System in the correct order. The planets Sun. The relative sizes of the objects are Mercury, Venus, Earth, Mars, Jupiter, are to scale, with 3200 km corresponding Saturn, Uranus, Neptune, and Pluto. to one pixel of the image. Mars is the fourth planet from the Sun. It If the relative sizes of the planets is one of the four inner planets. Mars were shrunk to be one billionth of its orbits at a distance of 1.52 Astronomical actual size, the Earth would be the size Units (227,940,000 km) from the Sun. of a large marble (2 cm diameter), Mars One Astronomical Unit is equal to 1.496 would be the size of a pea (1 cm x 108 km, the average distance from the diameter), Jupiter would be the size of a Earth to the Sun. Astronomical Units are grapefruit, Saturn would be the size of an abbreviated A.U. Its orbit is situated orange, Uranus and Neptune would each between those of Earth and the Asteroid be the size of lemons, and the Sun would Belt. be the size of a tall man. 4 Climate Orbiter was approaching the planet, shows the brightly lit side of Mars that is facing the Sun. The relative sizes of the Mercury, Venus, Earth, and Mars. NASA/JPL. Physical Properties and Composition While it is easy to compare the Mars has a mass of 6.4x1023 kg, relative sizes of the planets in an image, or about 100 times less than the mass of it is more difficult to compare their Earth. It has a diameter of 6,000 km, or relative distances from the Sun. If the about half that of Earth. The surface Solar System was shrunk to one billionth area of Mars is about the same as the of its actual size, the Moon would be land area of Earth. There is no evidence about 30 centimeters away from the of current plate tectonic activity or active Earth. The Sun would be 150 meters volcanism on Mars, although there is (one and a half football fields) away from evidence to suggest that such the Earth. Mars would be 325 meters phenomena have been present in the away (three football fields), Jupiter would past. Mars is made of an inner core with be 750 meters away (5 city blocks), a 1700 km radius, a molten mantle, and Saturn would be 1500 meters away (10 a very thin crust that ranges from 80 km city blocks), and the nearest star would to 30 km thick in places. The planet is be more than 40,000 km away (twice the made mostly of iron. In fact, iron oxide circumference of the Earth!) (rust) on the surface of Mars is what From the Earth, Mars looks like a makes the so-called “Red Planet” appear big, reddish star. A somewhat closer red. view as in this image taken as the Mars 5 greenhouse effect that raises the temperature on the planet about five degrees. The atmosphere is thick enough to produce very large dust storms that can be seen from Earth. The interior of Mars. NASA/JPL. A dust devil on Mars, taken by the Mars The surface of Mars. NASA/JPL. Global Surveyor. NASA/JPL. Because Mars is not very massive, it can retain only a thin atmosphere of mostly carbon dioxide. Carbon dioxide makes up 95.3 percent of the atmosphere, while nitrogen at 2.7 percent, argon at 1.6 percent, oxygen at 0.15 percent, and water at 0.03 percent make up the remainder. The carbon A Martian sunset, taken by the Imager for Mars Pathfinder. NASA/JPL. dioxide on Mars does produce a small 6 The red and blue colors in this the moon is only 22 km. It is very odd- Martian sunset are caused by absorption shaped, and has a mass of just 1.1x1016 and scattering of light by dust in the kg. It is composed mostly of carbon-rich atmosphere. rock and is heavily cratered. Most Mars also has ice caps on both its astronomers think that Phobos is a north and south poles. The ice caps captured asteroid. grow and shrink with the seasons, and Phobos orbits Mars very quickly. they are made of both carbon dioxide ice It usually rises, transverses the Martian (“dry ice”) and water ice. The ice caps sky, and sets twice every Martian day. can be seen from Earth. The moon is also very close to Mars’ surface. Just as an airplane flying over the Earth’s equator cannot be seen above the horizon for an observer in the United States, Phobos is so close to Mars’ surface that it cannot be seen above the horizon from all points on Martian North Polar Cap. NASA/JPL. Mars. As it orbits, it slowly spirals in towards the Martian surface. Phobos The Moons of Mars looses 1.8 meters of altitude per century, Mars has two moons named and in 50 million years it will either crash Phobos and Deimos, Greek for fear and into the surface or be destroyed in the panic. Phobos is the closer of the two, atmosphere. orbiting Mars 9378 km above the planet’s center. It is very small – the diameter of 7 Deimos, taken from the Viking 2 Orbiter. Phobos taken from the Viking 1 Orbiter. NASA/JPL. NASA/JPL. Mars Geography Deimos orbits farther out than Like Earth, the surface of Mars Phobos, and it is even smaller, with a has many kinds of landforms. Some of diameter of only 12.6 km and a mass of Mars’ spectacular features include 1.8E15 kg. In fact, Deimos is the Olympus Mons, the largest mountain in smallest known moon in the Solar the Solar System. The Tharsis Bulge is System. Like Phobos, Deimos is made a huge bulge on the Martian surface that of mostly cratered carbon-rich rock, is is about 4000 km across and 10 km high. very amorphous, and is thought to be a The Hellas Planitia is an impact crater in captured asteroid. Like our own Moon, the southern hemisphere over 6 km deep Deimos orbits far enough away from and 2000 km in diameter. And the Valles Mars that it is being slowly pushed Marineris, the dark gash in Mars’ surface farther and farther away from the planet. shown in the picture below, is a system 8 of canyons 4000 km long and from 2 to 7 km deep. Martian Topography. NASA/JPL. This is a map of Martian topography. In the left image, the Mars, taken by the Hubble Space Telescope. NASA/JPL. Tharsis Bulge can be seen in red and The white patches in the map of white. The Valles Marineris is the long the Martian surface shown below are blue gash through the middle. In the clouds and storms in Mars’ atmosphere. right image, the blue spot is the Hellas impact basin. Craters can also be seen in the right image. Mars with clouds and storms, taken by the Hubble Space Telescope. NASA/JPL. Mars Topography. NASA/JPL. This image is a flat map of Mars, made from data from an instrument aboard the Mars Global Surveyor. There 9 are striking differences between the Mountains northern and southern hemispheres. The picture below shows the The northern hemisphere (top) is Libya Montes, examples of mountains on relatively young lowlands. It is about 2 Mars. The Libya Montes were formed by billion years old. The southern a giant impact. The mountains and hemisphere (bottom) consists of ancient valleys were subsequently modified and and heavily cratered highlands, much eroded by other processes, including like the surface of the Moon. It is about 4 wind, impact cratering, and flow of liquid billion years old. There is a very clean water to make the many small valleys boundary between the two regions, that can be seen running northward in although the reason for this sharp break the scene.