MSIP Resource Manual

MARS STUDENT IMAGING PROJECT

Resource Manual

Mars Education Program Jet Propulsion Laboratory Arizona State University Version 2.00 The Mars Student Imaging Project

Written and Developed by:

Keith Watt, M.A., M.S. Assistant Director ASU Mars Education Program

Image Processing Curriculum by: Sara Watt, M.S. ASU Mars Education Program

Editing by:

Paige Valderrama, M.A. Assistant Director ASU Mars Education Program

Sheri Klug, M.S. Director ASU Mars Education Program

Chapter 1: Mars in Society and Culture

Mars has always played a significant role in human society. The early Greeks noted that unlike the other planets, Mars sometimes seemed to reverse its direction across the sky. This “contrary” motion suggested disorder and anar- chy to the Greeks, which, along with its reddish color, led them to name the planet after Ares, their god of war. The Romans later changed the planet’s name to that of their god of war, Mars, and the name has remained ever since.

In the Beginning Science and our view of the world with the theory, however. Careful ob- change only when we are presented servations showed that the planets did with some observation we can’t ex- not quite move in perfect circles. plain. Early Greek scientist-philoso- Faced with an observation that couldn’t phers believed that Earth was at the be explained with current theories, center of the Universe and all other Ptolemy modified Eudoxus’ theory and celestial bodies revolved around it. replaced his simple circles with a com- Eudoxus, a mathematician who lived plicated system of “epicycles”, circles in the fourth century B.C., was one of that interlock like gears in a complex the first people to propose this theory. machine. Ptolemy’s theory could de- Eudoxus’ version of the theory was el- scribe and predict the motions of the egantly simple: God is perfect, the planets with an accuracy never before only perfect forms are circles, there- achieved. For almost 1,400 years, fore the Sun and planets must move until the 16th century, Ptolemy’s in circles around the Earth. Claudius theory was considered to be the only Ptolemy, a Greek scholar who lived in correct theory of the Universe. The Alexandria, Egypt, around 140 AD theory was endorsed by the Catholic noted that there were some problems Church, which declared any other ex- planation for the planets’ motions to be heresy and punishable by death.

Ptolemy’s theory only had one prob- lem: it was wrong. One hundred years after Eudoxus, the astronomer Aristarchus watched the shadow of the Earth sweep across the surface of the Moon during a lunar eclipse. His observations showed that the Sun had to be much larger than the Earth, and he felt that it was not likely that a large The Ptolemaic Universe Credit: University of Tennessee 2 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

Sun would rotate around the smaller Johannes Kepler, the task of creating Earth. He proposed instead that the a mathematical description of Mars’ or- Earth revolves around the Sun. He bit. Tycho, however, was very protec- was condemned for heresy because of tive of his data, his theory and all of his writings were as are many sci- rounded up and destroyed. The only entists today. reason we know anything about He would throw Aristarchus at all is because he is men- out an observa- tioned in the writings of the great tion over dinner mathematician Archimedes. No other in casual con- scientist was willing to risk the wrath versation, which of the Church by mentioning the Kepler would astronomer’s work. In 1543, nearly frantically 2,000 years later, however, scrawl down in a Aristarchus’ theory was taken up by Johannes Kepler (1571-1630) notebook that Polish doctor, lawyer, and part-time as- Credit: University of St Andrews, Scotland he kept under tronomer Nicolaus Copernicus. the table. When Tycho finally died sev- Copernicus’ careful observations could eral years later, Kepler broke into not be explained by Ptolemy’s theory. Tycho’s safe and stole all of his data. Only if the Sun were at the center of Tycho’s family demanded the docu- the Solar System could his data make ments be returned, and Kepler did so sense. Once again, because of new – but only after he had made exact observations, new science and a new copies of all of the precious data. worldview was born. Kepler, like most of his fellow scientists, felt certain that the planets trav- The New Scientists eled in perfect circles. After years of Mars played a major role in the con- struggling with Tycho’s observations of troversy. Even Copernicus’ theory Mars, however, he finally reached the could not explain the strange motions inescapable conclusion that all the of Mars. In 1600 Tycho Brahe had un- work done before him was wrong: the dertaken the careful study of Mars’ or- planets move in ellipses, not circles. bit. Tycho was perhaps the greatest In addition, he discovered two other observational astronomer the world laws of planetary motion that he pub- has ever known. We can make more lished in 1609. Thanks to Mars, we accurate observations today only be- now understood not only its motion, cause we have more accurate instru- but the motion of the entire Solar Sys- ments. Tycho was world famous, a tem as well. rock star of science who toured the palaces of kings and other nobility all In 1634, Kepler published a book called over Europe. Tycho had given his stu- The Dream, in which he described a dent, a German mathematician named fanciful flight from the Earth to the 3 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

Moon. It was one of the first works of cifically to study Mars. His writings science fiction. Science fiction books ignited the imagination of generations have spurred generations of people to of people around the world, including wonder about the stars and the plan- great science fiction authors such as ets that travel through the heavens. Edgar Rice Burroughs (the Barsoom By the end of the 19th century, how- series of 11 novels), Ray Bradbury ever, improved telescopes showed that (The Martian Chronicles), and H.G. the Moon was a barren, desolate place, Wells (The War of the Worlds). Wells’ a place where no life could possibly work was made even more popular exist. Mars, however, was still a fuzzy when Orson Welles (no relation to H.G. disk in even the best telescopes. Sci- Wells) and his Mercury Theater on the ence fiction authors, scientists, and the Air performed the most famous radio imaginations of the general public play in American history. To celebrate turned away from the Moon and looked Halloween of 1938, Welles adapted instead to the Red Planet. In 1877, The War of Worlds, a tale of a Martian Italian astronomer Giovanni invasion of the Earth, into a radio Schiaparelli observed a series of lines broadcast. Story events were pre- that seemed to cross most of the sur- sented as “news broadcasts” report- face of Mars. In his notes, he called ing New York City in flames and un- these lines canali, an Italian word that stoppable aliens destroying everything means “channels”. American amateur in their paths. Millions of people, who astronomer Percival Lowell, however, tuned in to the play late, thought the translated the word as “canals”, a very broadcasts were real and fled their similar meaning, but one that has very homes in terror of the “invasion”. Most different implications: “canals” implies had taken to the streets in panic and intelligence. Lowell believed that never heard the play’s end and Welles’ Schiaparelli had discovered the engi- wish for them to have a happy Hal- neering works of a dying Martian so- loween. NBC issued a public apology ciety desperately trying to bring wa- the next day; Welles became one of ter from the Hollywood’s most successful actors. Martian icecaps Mars, and the possibility of life there, to the equatorial was so firmly ingrained in the minds lands. Lowell of the public that no one questioned was so excited that the events of that night might not by the discovery have actually been real. Mars has al- that he had a ways had this power over us. state-of-the-art observatory Today scientists know that Mars in its built in Flag- current form probably cannot support

Lowell’s drawing of Mars staff, AZ, spe- life as we know it. Spacecraft sent to Credit: The Wanderer Project 4 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

Mars have found no trace of Lowell’s it once have life? Where did all the “canals” or of his dying civilization. But water on Mars go? Could Earth also was Mars always as it is now? Data change as Mars has? These are just a returned from our Mars spacecraft few of the questions scientists hope show us that it almost certainly was to answer, important questions that not. At some time in the past, Mars you will also help to answer as you was much warmer and wetter than it begin your exploration in the Mars Stu- is today. What happened to Mars? Did dent Imaging Project.

The Inner Solar System Credit: Keith Watt 5 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

Chapter 2: Mars Exploration Background

As mentioned in Chapter 1, Mars has attracted the attention and imaginations of observers for thousands of years. The first serious observations of the Mar- tian surface were conducted by Schiaparelli in 1877, whose work was expanded upon by Lowell in 1890. Until the dawn of the space age in the early 1960’s, telescopic observations were the only way we could study Mars. Even the best telescopes, however, must still look up through the Earth’s atmosphere in order to see out into space. It’s a lot like trying to watch clouds from the bottom of a swimming pool: the objects are there, but they are fuzzy, wavering, and hard to make out. If we want to conduct serious observations of another planet, we need to go there.

The Mars Race On October 4, 1957, the Soviet Union the probe was lost. No one has ever launched Sputnik 1, the first man- determined what happened to the made object into space. In doing so, probe, but its loss gave the American they did more than launch a space- team another chance to be the first to craft, they launched a race that would Mars. ultimately end with the United States landing a total of 12 astronauts on the Thrilled with the success of Mariner 2, surface of the Moon. While many the first unmanned mission to Venus, people are familiar with the Moon NASA began its program of Mars ex- Race, not many people realize that ploration, hoping to be the first coun- there was a “Mars Race” as well. In try to explore Mars as well. Approxi- 1960, the Soviet Union attempted to mately every two years the planets are launch two robotic space probes to in just the right position for an Earth- Mars. Both exploded at launch. In Mars trip that requires the least 1962, however, amount of fuel. In 1964, NASA pre- they successfully pared to launch Mariner 3 and Mari- launched their Mars 1 probe and put it on course for the Red Planet. All seemed to be go- ing well until the spacecraft was about halfway to Mars. Suddenly, Sputnik all contact with Mariner 4 Credit: NASA Credit: NASA/JPL 6 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

ner 4 to Mars. During the launch of solved its difficulties and sailed on to Mariner 3, the spacecraft’s protective Mars. On July 15, 1965, Mariner 4 launch shroud collapsed, destroying became the first spacecraft to visit the spacecraft. With only three weeks Mars. The spacecraft returned 21 im- remaining in the low-fuel launch win- ages that revealed the dry, cratered dow, NASA engineers scrambled to get surface of Mars. Dreams of a garden Mariner 4 ready to take the place of planet were laid to rest forever, but its sister spacecraft. On November 28, the data showed that Mars was a fas- 1964, Mariner 4 launched successfully cinating planet in its own right. and put onto the path to Mars. The Soviet Union was not far behind, how- Missions to Mars continued with Mari- ever. Two days later, on November ner 6 and Mariner 7 in 1969, both per- 30, they launched Zond 2 and put it forming flyby missions similar to Mari- on course to Mars as well. There was ner 4. Mariner 6 performed flawlessly, now a literal race to the Red Planet. but Mariner 7, during its mission, sud- Two spacecraft were headed to Mars. denly lost contact with Earth. Engi- Which would get there first? neers were afraid the “ghoul” had returned, but they managed to re-es- The race stayed close for the first tablish contact and determined that a months of the trip, but just as Zond 2 battery on board had exploded during reached the point near where Mars 1 the pass behind the planet. The con- vanished, it too lost all communica- trollers instructed Mariner 7 to shut tions. NASA engineers joked about a down its damaged systems and con- “Great Galactic Ghoul” that ate Mars tinue the mission. The two spacecraft spacecraft. They stopped laughing together returned 58 pictures of the when Mariner 4 began having commu- Martian surface taken from a distance nications difficulties in the same area. half as far from the planet as Mariner Unlike Zond 2, however, Mariner 4 re- 4. The images, and particularly those from Mariner 7’s flight over the Mar- tian polar caps, once again changed the way we view Mars. Mariner 7 carried an infrared spectrometer on board that was able to analyze the composition of the ice. The spacecraft discovered that the south polar cap of Mars is not water ice at all, but is instead composed almost entirely of frozen carbon dioxide, or “dry ice”.

Zond Credit: Lunar and Planetary Institute 7 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

Mariner 9 NASA engineers quickly realized that after launch. The fleet of spacecraft in order to carefully study a planet, headed to Mars had been reduced from you have to not only go there, you five to three in just a few weeks. have to stay. What was needed was a spacecraft that would travel to Mars The three remaining craft, the Soviet and place itself in orbit around the Mars 2 and Mars 3 and the American planet. The United States was not Mariner 9, were all launched in May of alone in this assessment. The Soviet 1971. Once again, the race to Mars Union designed three spacecraft that was on. The race was won by Mariner would travel to Mars during the next 9, which was on a slightly faster course launch window. In 1971 they were to than its Soviet counterparts. On No- join the American Mariner 8 and Mari- vember 14, 1971, Mariner 9 became ner 9 probes on the long journey to the first artificial satellite of another the Red Planet. The Soviets, however, planet. Mars 2 arrived two weeks later were attempting to leapfrog the United and Mars 3 shortly after that. Unfor- States: each of their spacecraft con- tunately, when the three spacecraft ar- tained not only an orbiter, but also a rived at Mars, there was nothing much lander designed to descend and send to see. In September of 1971 a dust back the first pictures from the sur- storm, visible from Earth, began which face of Mars. The American Mariner 8 eventually covered the entire planet. spacecraft died when the second stage Nothing of this scale had ever been of its Atlas-Centaur booster rocket observed on any planetary body. The failed to ignite. The Soviet Cosmos Soviet Mars 2 dispatched its lander 419 made it into space, but never left anyway, as it programmed to do, but Earth orbit because the ignition timer the lander crashed on the surface, for its last stage had been mistakenly sending back no data. Mars 3’s lander set for 1.5 years rather than 1.5 hours faired a bit better, sending back a few seconds of data before it was blown over and destroyed by the raging Mar- tian winds. Still, the Soviet Union had become the first nation to land a spacecraft on another planet – even if it didn’t do much once it got there. The Soviet orbiters snapped feature- less pictures of the dust-enshrouded planet until their batteries died. Noth- ing could be seen through the dust on any of the images. Mariner 9, however, had been designed with an on- Mariner image of cratered area on Mars board computer that could be repro- Credit: NASA 8 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

grammed from Earth. NASA control- and the three Tharsis Montes volca- lers instructed the spacecraft to shut noes, each larger than any volcano on itself down and conserve power until Earth. The spacecraft also discovered the storm passed. By December of Valles Marineris, the largest canyon 1971, the storm was over and NASA system in the Solar System, formed woke up the sleeping spacecraft, which when some cataclysmic event caused returned the highest resolution pic- the crust of Mars to bulge so much it tures of Mars that had ever been ob- cracked. The canyon is so huge, if tained. placed on the Earth it would extend from San Francisco to Washington, Once again, new observations com- D.C. The entire Grand Canyon would pletely changed everything we thought fit in one of its side canyons. Most we once knew. Observations of Mars significantly, Mariner 9 discovered long by previous spacecraft had led us to channels that look unmistakably like believe the surface of Mars was a dry riverbeds – indicating that Mars cratered, dead landscape, not much may have once had liquid water. These different from Mercury or the Moon. and other wonders were returned to All of those spacecraft, however, had Earth in the 7,329 images sent back flown past only the southern hemi- to Earth during the course of Mariner sphere of Mars. The northern hemi- 9’s year-long mission. The spacecraft sphere of Mars is made up of smooth ran out of fuel on October 27, 1972, plains and lava basins, totally unlike and went forever silent. the cratered south. Mariner 9 also solved the mystery of the “seasonal The Viking Missions variations” Mars seems to display. NASA missed the next launch window These dark areas on the surface seem in 1973 because it was preparing for to change location with the seasons an even more ambitious mission: a and were thought to be indications of large-scale lander that would carry a plant life growing during the warmer Martian summers. Mariner 9 found that the dark areas were just huge areas of dark rock exposed when the bright red Martian dust was blown away by surface winds. As the seasons changed, so did the direction of the winds, uncovering new dark re- gions. The three previous Mariner spacecraft sent to Mars had shown no indication of volcanic activity. Mari- ner 9 discovered Olympus Mons, the Viking orbiter largest volcano in the Solar System, Credit: NASA/JPL 9 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

complete laboratory to the surface of experiments did not in fact detect life Mars. The Soviet Union was not idle, on Mars. The question still remains, however, using the 1973 launch op- however: even if there is no life on portunity to send four spacecraft to the Mars now, did life ever exist there in Red Planet. None were successful. By its past? The question is still unan- 1975, the American Viking 1 and Vi- swered. king 2 spacecraft were launched and headed to Mars. Like their Soviet With the end of the Apollo lunar pro- counterparts, each Viking spacecraft gram, NASA’s shrinking budget forced carried both an orbiter and a lander. it to concentrate on the Shuttle Trans- The landers carried no less than 14 portation System, better known as the different experiments, most of which Space Shuttle. As a result no Ameri- were designed to detect life on the sur- can spacecraft visited Mars for nearly face. The trouble was that no two sci- twenty years. The Soviet Union (which entists agreed upon a definition of life, would simply become Russia the fol- much less the means to test for it. lowing year) launched Phobos 1 and 2 Both landers touched down safely, Vi- in 1988 to study the moons of Mars, king 1 on July 20, 1976, and Viking 2 but the “Great Galactic Ghoul” struck on September 3, 1976. The landers once again: Phobos 1 was lost en route immediately began the tests for life to Mars just one month after launch. that were finally worked out as the Phobos 2 arrived near Mars and man- best that could be done. The experi- aged to perform, among other things, ments initially caused great excite- important studies of the solar wind ment when they indicated they might near Mars before a computer failure have actually found biological activity caused controllers to lose contact with in the Martian soil. Later analysis of the spacecraft just before reaching its the results, however, indicated that the destination. Neither mission was excitement was misplaced. Today, counted as a success. most scientists believe that the Viking

Mockup of Phobos Viking lander Credit: High Energy Astrophysics Science Archive Research Center Credit: NASA 10 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

In 1992, the United States decided to but it also included something never return to the Red Planet and renew its before attempted: an independent studies of this fascinating world. As rover, named Sojourner, capable of with the Russian spacecraft, Mars Ob- traveling up to ten meters (32 feet) server lost contact with Earth a year away from the lander. The mission later just as it was about to enter or- tested a number of new technologies. bit around Mars. The Mars Observer Instead of using a Viking-style mission cost nearly one billion dollars. retrorocket, the Pathfinder lander was It would be the last of the “old-style” encased in four large six-chambered planetary explorers. air bags. Upon entering the Martian atmosphere, the lander parachuted Faster, Better, Cheaper most of the way to the surface, then Under the leadership of its new ad- deployed and inflated its air bags for ministrator, industrialist Dan Goldin, landing. The spacecraft bounced 15 NASA decided to try a new approach to 20 times, sometimes as high as 50 dubbed “faster, better, cheaper”. The feet. The landing went exactly as idea was to use many, smaller space- planned. On July 4, 1997, Pathfinder craft, instead of one huge expensive opened its landing petals, and began spacecraft. In this way, the loss of its science mission while sending the one craft would not doom an entire Sojourner rover on its way. The mis- exploratory mission. The first in this sion was a complete success. The series of “Discovery missions” was lander returned over 16,500 images, Mars Pathfinder. In contrast to the some in 3D. The rover returned over billion-dollar Mars Observer mission, 550 images but, more importantly, Pathfinder was designed, built and sent back over 15 chemical analyses launched for only 250 million dollars, of rocks and soil, as well as data on one-fourth the cost of Observer. Like Martian winds and weather. On Sep- Viking, Pathfinder included a lander, tember 27, 1997, the Pathfinder lander, now called Sagan Memorial Station, failed to answer a routine sta- tus check. Controllers tried for several months to reach the silent craft, but finally gave up on March 10, 1998, officially ending one of the most successful Mars missions in history.

Although launched a month earlier than Mars Pathfinder, an orbiter called Mars Global Surveyor actually arrived at Mars after Pathfinder. Mars Global Pathfinder Lander and Rover Surveyor was designed to use a tech- Credit: NASA/JPL 11 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

nique called “aerobraking”, in which topography – terrain heights – of Mars. the spacecraft dips into the Martian at- The spacecraft completed its primary mosphere to slow down and place it- mapping mission on January 31, 2001, self in Mars orbit. Aerobraking is a but was in such good health, mission delicate maneuver. If the spacecraft managers decided to extend the mis- enters too low into the atmosphere, it sion and to continue gathering data. will burn up. The spacecraft spent al- It was fortunate that they did so, as most a year and half slowly modifying on June 15, 2001, Global Surveyor its orbit around Mars until it was in a scientists detected the beginnings of nearly circular polar orbit. This orbit what would become the largest global would allow Global Surveyor to image dust storm since the Mariner 9 mis- virtually the entire planet during the sion almost exactly thirty years prior. course of its two-year science mission, which began in March of 1999. Like Flush from the successes of Mars Path- Pathfinder, Global Surveyor has been finder and Global Surveyor, NASA com- a phenomenal success, returning more missioned two more spacecraft for the data about the Martian surface and at- 1998-99 launch window. Mars Climate mosphere than all previous Mars mis- Orbiter was to function as a Martian sions combined. The spacecraft car- weather satellite and as a communi- ried not only a camera (the Mars Or- cations relay satellite for the other biter Camera, or MOC), it also carried craft, Mars Polar Lander. Polar Lander an infrared spectrometer (the Thermal was to land near the south polar ice Emission Spectrometer, or TES) de- cap of Mars and dig under the surface signed to search for minerals and mea- in search of water ice. It also carried sure the temperature of Mars, as well two “penetrators”, called Deep Space a laser altimeter (the Mars Orbiter La- 2 (Deep Space 1 was a probe designed ser Altimeter, or MOLA) which provided to study comets using an experimen- the first accurate measurement of the tal ion propulsion unit). Unfortunately,

Mars Global Surveyor Mars Polar Lander Credit: NASA/JPL Credit: NASA/JPL 12 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

Climate Orbiter suffered from human- it simply landed in rough terrain and caused failure, similar to that which was unable to point its antenna at struck the Soviet Cosmos 419 in 1971. Earth. This last theory is particularly Navigation parameters were fed to the ironic: the spacecraft could have been spacecraft in English units, when the completely healthy, it just needed program was designed to use metric someone to kick it back upright. units. The spacecraft disappeared be- Strangely, though, nothing was heard hind Mars on September 23, 1999, and from the Deep Space 2 penetrators ei- never reappeared. The fate of Polar ther, even though they were deployed Lander is still unknown. The space- early in Polar Lander’s descent. We craft seemed to be functioning nor- may never know what happened to mally as it entered the Martian atmo- Mars Polar Lander – at least not until sphere, but no signal from the surface we are able to go there and look at was ever received. Theories include the crash site ourselves. that Polar Lander burned up on entry, crashed into the surface, or perhaps

Mars Global Surface Map Credit: NASA 13 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

Chapter 3: Mars in the Solar System

Mars is a world of puzzles. It is both very similar to and very different from our own Earth. Mars is the fourth planet from the Sun and orbits at a distance one and a half times that of Earth’s orbit. As a result, Mars receives much less light and heat from the Sun than the Earth does, so it is much colder. Also, unlike the Earth, Mars has a very thin low-pressure atmosphere which is unable to retain what heat it does receive. Because of the temperatures and pressures on the Martian surface today, water cannot exist in liquid form. Mars today is therefore a dry, frozen desert.

Similarities and Differences Mars is similar to Earth in a number of Venus is a hothouse, with tempera- important ways. It has an axial tilt of tures soaring to hundreds of degrees 23.98 degrees, very similiar to Earth’s centigrade and atmospheric pressures 23.44 degrees. Mars therefore has high enough to crush our toughest seasons, just like Earth, with cold win- metals like tin cans. Mars, on the other ters and warmer summers. Mars’ ro- hand, could one day conceivably be tation period, its “day”, is 24 hours, changed to be more like Earth through 37 minutes, again almost exactly the advanced engineering known as same as Earth’s. Like Earth, Mars has “terraforming”. In many respects, ice caps at both poles. It has clouds, Mars is a much more hospitable envi- winds, weather, dust storms, volca- ronment than Venus, making it an noes, and channels. For many years, obvious target for our imaginations. Venus was considered the “twin” of Earth. Unlike Mars, Venus is very simi- But Mars is very different from Earth lar in size and mass as Earth and as well. Surface temperatures on Mars therefore has very similar gravity. But range from hundreds of degrees centigrade below zero in the winter to nearly freezing (0º C) in the summer. Because Earth’s orbit is nearly circular, our seasons are virtually the same in both hemispheres. Mars travels in a more elliptical orbit around the Sun than does the other planets, so it is 20% closer to the Sun during southern summer than it is in northern summer. This results in very long, relatively warm southern summers and

Earth/Mars Comparison very long, cold northern winters. Mars Credit: NASA/JPL has an atmospheric pressure less than 14 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

seven-tenths of one percent of Earth’s, activity not long after the period of far too low to sustain most forms of major impacts. Mars, however, was life as we know it. The southern ice geologically active for most of the life cap is made mostly of frozen carbon of the Solar System – the great vol- dioxide (“dry ice”), not water. Much cano Olympus Mons was probably ac- of the surface of Mars is covered with tive just thirty million years ago – so craters much like the Moon. All of has examples of young terrain in the these differences make Mars a world north right alongside the ancient unto itself, rather than a “twin” of Earth cratered terrain in the south. In many or another planet. ways, Mars uniquely records the history of the Solar System in its surface The northern and southern hemi- features. spheres of Mars are very different. In general, the south is very heavily Polar Caps cratered, while the north is made up The polar caps of Mars change dra- mainly of smooth dark plains. There matically over the course of a Martian are many exceptions to this general year (which is almost two Earth years). rule, for example, Hellas Planitia During each hemisphere’s winter, car- (planitia are smooth, low plains or ba- bon dioxide freezes out of the atmo- sins) lies in the southern hemisphere sphere at the poles to form “dry ice”. and, at 3 km below “datum”, is the This dry ice causes the polar cap in deepest basin on Mars. The word “da- that hemisphere to grow by a substan- tum” is used rather than “sea level”, tial amount. As much as one-third of because, obviously, Mars currently has the atmosphere of Mars freezes into no seas! The datum is defined as the dry ice at each pole during winter in altitude at which the atmospheric pres- its hemisphere. Changes of this mag- sure is 6.1 millibars (6.1 thousandths nitude in the atmospheric pressure of of the sea level pressure on Earth). the Earth would signal that a storm of The planet isn’t spherical either. There is a very large bulge in the crust lo- cated at around 113º west longitude. This region, called the Tharsis Bulge, is home to the largest volcanoes on Mars – and in the entire Solar Sys- tem. The southern hemisphere reveals the ancient cratering record of impacts early in the Solar System’s history. On Earth, this record has been virtually erased by the effects of volcanoes, wind, and water. Planets such as Mer- Mars South Polar Cap, Summer 2000 cury died young, ceasing geological Credit: Malin Space Science Systems 15 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

unprecedented power was forming, side of the crater rather than simply but on Mars it is just a part of the falling straight back to the surface. yearly cycle. In the summer, the tem- Craters of this type are called rampart perature rises above the vapor point craters because the ejecta is made up of carbon dioxide and therefore the dry of sheets that have distinct outer ice sublimates back into the atmo- ridges, or ramparts. sphere. The polar cap then begins to shrink, though there is always some Another unique type of crater on Mars ice left at the poles. The two poles is the pedestal crater. This type of cra- are not the same, however. The ice ter is found largely in the northern that remains at the north pole during hemisphere. Craters of this type seem the northern hemisphere’s summer is to sit upon a raised pedestal of ejecta. mostly water ice, while the residual ice Some of these craters also show ridges at the south pole is still mostly carbon like rampart craters, but in other cases dioxide ice. Scientists assume that the ridges have been eroded away by there is water ice buried below the dry wind. In some cases the pedestal cra- ice at the south pole. Mars Polar ter looks to be situated atop a flat, Lander was intended to resolve this raised plateau which rises above the particular question once and for all surrounding terrain. (but unfortunately did not). Any of these types, including the more Craters “standard” lunar-type crater can be As with Earth and the Moon, Mars was made into an incomplete circle by lava bombarded with debris left over from flows covering part of the rim. These the formation of the Solar System. flooded craters are particularly com- The craters left behind have many of mon near the Tharsis Montes volca- the same properties as those on the noes. Moon: a nearly circular raised rim, steep walls, and a smooth floor. If the debris hit with enough energy to liq- uefy the surface at impact, a central peak often formed in the center of the crater floor. Ejecta, material blasted into the air from the impact, fell in a blanket that extends outward from the crater. Unlike the Moon, however, ejecta blankets on Mars do not have a perfectly circular form. Many craters have irregular ejecta blankets that seem to indicate that some of the ejecta flowed across the surface out- Belz Crater, Chryse Planitia, Mars Credit: NASA 16 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

Wind Features Although Mars has a very low atmo- Mars built up into major eruptions that spheric pressure, the surface winds are always occurred in the same places – very fast. Wind effects are respon- the weak points in Mars’ stable crust. sible for many of the features that are One of the most significant features seen on Mars today. Sand dunes, very influencing the development of volca- similar to those seen on Earth, are noes, however, is the Tharsis Montes abundant in the northern hemisphere. bulge. The bulge is the site of Olympus These dunes form in broad lines that Mons, the largest volcano in the Solar run perpendicular to the wind direc- System, as well as the three Tharsis tion. By tracking these dunes, we gain Montes volcanoes, each larger than some idea of how the Martian winds any volcano on Earth. Olympus Mons flow over time. The wind is also re- is 22 km (13.75 miles) high and 550 sponsible for eroding the Martian land- km (343.75 miles) in diameter. If scape, often in strange and bizarre placed on the surface of the Earth, it shapes. The wind is strong enough to would be two and a half times the blow the red dust away to expose height of the tallest mountain on Earth darker-colored rock below, an effect (Mt. Everest at 8.85 km or 5.5 miles) which, as mentioned in Chapter 2, and would cover almost the entire once convinced scientists that Mars state of Arizona! Numerous other vol- was covered with vegetation. canoes dot the region as well. These volcanoes were almost certainly Volcanoes formed from lava upwelling through Mars has the largest volcanoes in the vents in the fractures created by the Solar System. One theory why this is bulge. No one really knows what true is that Mars seems to have a much formed the bulge. A number of theo- thicker crust than Earth, and so it ries have been proposed, but none doesn’t have floating, moving crustal have yet been proven. Mars has no plates. Instead of lots of compara- magnetic field to speak of, so it prob- tively small eruptions, as occurs with ably has no molten, liquid core as the volcanoes on Earth, the pressure on Earth does. Some rocks, however, do show “frozen-in” magnetic field lines, which could be evidence that Mars had a strong magnetic field – and therefore a liquid core – in the past. What happened to the core to cause it to solidify? What formed the Tharsis bulge? These are some of the puzzles that Mars presents to us today.

Olympus Mons Credit: Goddard Space Flight Center 17 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

Canyons Canyons exist in many places on Mars, flowing out of the canyon after it was but none are as famous as Valles formed. Unlike most canyons on Marineris (“The Valley of the Mariners”, Earth, Valles Marineris was not formed named for the American probes sent by flowing water. The canyon is an- to Mars). The largest canyon in the other effect of Solar System, Valles Marineris is even the Tharsis visible from Earth. The canyon is not bulge. One actually a single canyon, but is instead theory is that it a system of interconnecting canyons. was formed by a Valles Marineris varies in depth, but literal ripping reaches a maximum over 7 km (4.37 apart of the Mar- miles). Individual canyons are as tian crust during much as 200 km (125 miles) wide. the event that The central section of Valles Marineris caused the is made up of three nearly parallel can- Tharsis bulge. yons, having a total width of over 700 Another theory km (437.5 miles) and nearly 2,400 km proposes that the (1,500 miles) in length. The total canyon was length of the Valles Marineris system formed when is over 4,000 km (2,500 miles). The magma under- Nanedi Vallis canyon is divided into three general neath it was Credit: Malin Space Science Systems parts. In addition to the central sec- drawn out in the eruptions of the tion, to the west, near the Tharsis Mon- Tharsis Montes. Once again, we have tes, is an extremely complex system many puzzles, but very few answers. of interlocking canyons called Noctis Labyrinthus. The eastern end of the Channels canyon is a region of chaotic terrain As mentioned previously, Mars today that could be the result of huge floods cannot have liquid water present on its surface. We have ample evidence, however, that Mars did at one time have water flowing across its surface. Much of this evidence is in the form of channels that appear to be the result of water runoff and outflows from flooding. We know some channels were formed by flooding that resulted when large impact craters were formed on the surface. The force of the impact melted the permafrost (a layer of ice that scientists think lies frozen Central Valles Marineris Credit: NASA 18 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

beneath the Martian surface) and argon. The remaining 1% is mostly caused the resulting water to flow vio- oxygen, carbon monoxide, and water lently away from the crater. This wa- vapor. We believe that much of the ter eventually refroze or evaporated water on Mars is frozen at the poles into the atmosphere. In addition to and under the ground in a layer called water-created channels, channels “permafrost”, but some of it actually could also have been formed by flow- exists as ice-crystal clouds that float ing lava. Channels formed by water in the atmosphere. These clouds don’t and channels formed by lava have very look like the fluffy cumulus clouds we different appearances. The character- see here on Earth, but they can re- istics of the channel (its walls, its semble the thin, wispy cirrus clouds floors, whether or not it has tributar- we often see high in our atmosphere. ies, etc.) also tell us something about Where different air masses come to- how much water was present and how gether, cyclones can form on Mars, just fast it was flowing. The questions of as they do on Earth. The most strik- what happened to the water on Mars ing features of the Martian atmo- and what the surface of Mars was like sphere, however, are the dust storms, when water flowed across it are the which can grow strong enough to cover central questions facing Mars scientists the entire planet. In addition to the today. Our experience on Earth has dust storm of 1971, which blocked been that where there is water, there Mariner 9’s view of the planet, in 1977 is life. Is the same thing true on Mars? the Viking orbiters observed no fewer than 25 major dust storms, two of Atmosphere which grew to global proportions. In The atmosphere of Mars is very thin, 2001, the Mars Global Surveyor space- but Mars still has weather! The atmo- craft was fortunate to witness the for- sphere is composed of about 95% car- mation and growth of the largest dust bon dioxide, 2.5% nitrogen, and 1.5% storm since the 1971 storm. We have learned a great deal about how the surface of Mars and its atmosphere interact as a result of seasonal heat- ing. This is information that we can use here on Earth as we try to understand our weather and its interactions with the surface.

Local Dust Storm on the Surface of Mars Credit: NASA 19 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

Chapter 4: The 2001 Mars Odyssey Spacecraft

(Note: Much of this material was taken from official NASA sources. The au- thor gratefully acknowledges their assistance!)

2001 Mars Odyssey is an orbiting spacecraft designed to determine the composition of the planet’s surface, to detect water and shallow buried ice, and to study the radiation environment near Mars. The mission will last for at least two Martian years, or almost four Earth years.

Overview The surface of Mars has long been space onboard a Delta II rocket thought to consist of a mixture of rock, launched from Space Launch Complex soil and icy material. However, the ex- 17A at Cape Canaveral Air Station, act composition of these materials is Florida. Sixty-six seconds after liftoff, largely unknown. Odyssey will collect the first six solid rocket strap-ons were infrared and visible images that will discarded. The remaining strap-on be used to identify the minerals rocket boosters were then ignited, and present in the soil and rocks on the when their fuel was expended, were surface to study small-scale geologic jettisoned. About 4 minutes, 23 sec- processes and landing site character- onds after liftoff, the first stage, the istics. By measuring the amount of lower section of the Delta II booster, hydrogen in the upper meter of soil stopped firing and was discarded eight across the whole planet, the space- seconds later. About six seconds after craft will help us understand how much that, the engine for the second stage water may be available for future ex- (the middle sec- ploration. The spacecraft will addition- tion of the Delta II ally give us clues about the planet’s booster) was ig- climate history. Furthermore, the or- nited. The fairing, biter will collect data on the radiation or nose-cone en- environment to help assess potential closure of the risks to any future human explorers. launch vehicle, Finally, the spacecraft can act as a was discarded 4 communications relay for future Mars minutes, 42 sec- landers. onds after liftoff. The second-stage Launch and Interplanetary burn ended about Cruise Injection 10 minutes after Odyssey’s mission to Mars began at liftoff.

11:02 a.m. Eastern time on April 7, The Delta II rocket 2001, as the spacecraft roared into Credit: Boeing 20 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

At this point, the vehicle was in a low- the signal from the spacecraft. At Earth orbit at an altitude of 195 kilo- 11:55 a.m. Eastern time, flight con- meters (120 miles). The vehicle trollers at NASA’s Jet Propulsion Labo- coasted for several minutes, and once ratory received the first signal from it was at the correct point in its orbit, the spacecraft through the Deep Space the second stage was restarted for a Network (DSN) station in Canberra, brief second burn. For stability, small Australia, indicating that all was well rockets then fired to spin the third aboard the orbiter. stage on a turntable attached to the second stage. The third stage sepa- Interplanetary Cruise rated and ignited its motor, sending The interplanetary cruise phase is the the spacecraft out of Earth orbit. Af- period of travel from the Earth to Mars ter the final burn, the third stage and and lasts about 200 days. It begins the attached spacecraft were despun with the first contact with DSN after so that the spacecraft could be sepa- launch and extends until seven days rated and placed into its proper cruise prior to arriving at Mars. Primary ac- orientation. This was accomplished by tivities during the cruise include check- a set of weights that were reeled out out of the spacecraft in its cruise con- from the side of the spinning vehicle figuration, check-out and monitoring on flexible lines, much as spinning ice of the spacecraft and the science in- skaters slow themselves by extend- struments, and navigation activities ing their arms. Approximately 30 min- necessary to determine and correct utes after liftoff, the spacecraft sepa- Odyssey’s flight path to Mars. rated from the Delta’s third stage, and the remaining spin was removed us- Odyssey’s flight path to Mars is called ing the orbiter’s onboard thrusters. a Type 1 trajectory, which takes the The solar array was deployed so that spacecraft less than 180 degrees the Deep Space Network could acquire around the Sun. During the first two months of cruise, only the Deep Space Network station in Canberra was capable of viewing the spacecraft. Late in May, California’s Goldstone station was able to view Odyssey, and by early June, the Madrid station was also able to track the spacecraft. The project also added the use of a tracking station in Santiago, Chile, to fill in tracking coverage early in the mission.

The orbiter transmits to Earth using DSN antenna in Goldstone, CA Credit: InterPlanetary Network and Information Systems Directorate its medium-gain antenna and receives 21 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

commands on its low-gain antenna total of five times to adjust its flight during the early portion of its flight. path. The first of these trajectory cor- About 30 days after launch, the or- rection maneuvers (TCM) was sched- biter was commanded to receive and uled for eight days after launch, and transmit through its high-gain an- it corrected launch injection errors and tenna. Cruise command sequences are adjusted the Mars arrival aim point. It generated and uplinked approximately was followed by a second maneuver once every four weeks during one of 90 days after launch. the regularly scheduled Deep Space Network passes. The remaining three trajectory correction maneuvers were used to direct The spacecraft determines its orien- the spacecraft to the proper aim point tation in space chiefly via a star cam- for insertion into Mars orbit. These ma- era and a device called an inertial mea- neuvers were scheduled at 40 days be- surement unit. The spacecraft flies fore arrival (September 14), seven with its medium- or high-gain antenna days before arrival (October 17) and pointed toward the Earth at all times, seven hours before arrival (October while keeping the solar panels pointed 24). The spacecraft communicated toward the Sun. The spacecraft’s ori- with Deep Space Network antennas entation is controlled by reaction continuously for 24 hours around all wheels (devices with spinning wheels of the trajectory correction maneu- similar to gyroscopes). These devices vers. Maneuvers were conducted in a are occasionally “desaturated,” mean- “turn-and-burn” mode, in which the ing that their momentum is unloaded spacecraft turned to the desired burn by firing the spacecraft’s thrusters. attitude and fired the thrusters. It was not Earth-pointed during the thruster During interplanetary cruise, Odyssey firing, so no communication was ex- was scheduled to fire its thrusters a pected in this short but critical time period.

Science instruments were powered on, tested and calibrated during cruise. The Thermal Emission Imaging Sys- tem (THEMIS) took a picture of the Earth/Moon system about 12 days after launch confirming that THEMIS was operating normally. Star calibration imaging was performed 45 days after launch. Two calibration periods for the gamma ray spectrometer were con- 2001 Orbiter Interplanetary Trajectory ducted during cruise. Each of the Credit: NASA/JPL 22 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

spectrometer’s three sensors could be the upper part of the planet’s atmo- operated during the calibration peri- sphere. During each of its long, ellip- ods depending upon spacecraft power tical loops around Mars, the orbiter capabilities. The Mars Radiation Envi- passed through the upper layers of the ronment Experiment (MARIE) was de- atmosphere each time it made its clos- signed to collect radiation data con- est approach to the planet. Friction stantly during cruise to help determine from the atmosphere on the space- what the radiation environment is craft and its wing-like solar array throughout the journey to Mars. caused the spacecraft to lose some of its momentum during each close approach, known as “a drag pass.” As the spacecraft slowed during each close approach, the orbit gradually lowered and circularized.

Following aerobraking walk-out, the final stage of the aerobraking process, the orbiter was in an elliptical orbit with a periapsis (closest point) near a 120 Image of Earth taken by THEMIS kilometer (75 mile) altitude and an Credit: Arizona State University apoapsis (furthest point) near the desired 400 kilometer (249 mile) alti- Mars Orbit Insertion (MOI) and tude. Periapsis was near the equator. Aerobraking A maneuver to raise the periapsis was Odyssey arrived at Mars on October performed to achieve the final 400 ki- 24, 2001 Universal Time (October 23 lometer (249 mile) circular science or- in the United States). As it neared its bit. The transition from aerobraking closest point to the planet over the northern hemisphere, the spacecraft fired its 640-newton main engine for 20 minutes, 19 seconds to allow itself to be captured into an elliptical, or looping, orbit around Mars. After cap- ture, Odyssey looped around the planet every 18.5 hours.

Aerobraking is the transition from the initial elliptical orbit to the two-hour circular science orbit. It is a technique that slows the spacecraft down by us- Predicted Aerobraking orbits ing frictional drag as it flies through Credit: NASA/JPL 23 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

to the beginning of the science orbit ditions are most favorable for specific required about one week. The high- instruments. gain antenna was deployed during this time and the spacecraft and science The relay phase begins at the end of instruments were checked out. the primary science mission in approximately two to five years. During this Mapping Orbit and Communica- phase, the orbiter will provide com- tions Relay Phases munication support for U.S. and inter- The science mission began in Febru- national landers and rovers. ary of 2002. The primary science phase will last for 917 Earth days. The Thermal Emission Imaging Sys- science orbit inclination is 93.1 degrees tem (THEMIS) or almost perpendicular to the Mar- By looking at the visible and infrared tian equator. This is a nearly polar (90 parts of the electromagnetic spectrum, degree inclination) orbit, but the ac- THEMIS will determine the distribution tual poles themselves will not directly of minerals on the surface of Mars and pass under the spacecraft. The orbit help understand how the mineralogy period will be just under two hours. of the planet relates to the landforms. Successive ground tracks (areas that During the Martian day, the sun heats pass underneath the spacecraft) are the surface. Surface minerals radiate separated in longitude by approxi- this heat back to space in characteris- mately 29.5 degrees and the entire tic ways that can be identified and ground track nearly repeats every two mapped by THEMIS. At night, since sols, or Martian days of 24 hours, 37 THEMIS maps heat, the imager will minutes. search for active thermal spots and may discover “hot springs” on Mars. During the science phase, THEMIS will take multi-spectral thermal-infrared In the infrared spectrum, the instru- images to make a global map of the ment uses nine minerals on the Martian surface, and spectral bands will also acquire visible images with a to help detect resolution of about 18 meters (59 minerals within feet). The Gamma Ray Spectrometer the Martian ter- (GRS) will take global measurements rain. These during all Martian seasons. The Mars spectral bands, Radiation Environment Experiment similar to (MARIE) will be operated throughout ranges of col- the science phase to collect data on ors, serve as the planet’s radiation environment. spectral “fin- Opportunities for science collection will gerprints” of be assigned depending on when con- Thermal Emission Imaging System Credit: Raytheon Santa Barbara Remote Sensing 24 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

particular types of geological materi- oxygen, iron, magnesium, potassium, als. Minerals, such as carbonates, sili- aluminum, calcium, sulfur, and carbon. cates, hydroxides, sulfates, hydrother- Knowing what elements are at or near mal silica, oxides and phosphates, all the surface will give detailed informa- show up as different colors in the in- tion about how Mars has changed over frared spectrum. This multi-spectral time. To determine the elemental method allows researchers to detect, makeup of the Martian surface, the in particular, the presence of minerals experiment uses a gamma ray spec- that form in water and to understand trometer and two neutron detectors. those minerals in their proper geologi- When exposed to cosmic rays (charged cal context. particles in space that come from the stars, including our Sun), chemical el- Using visible imaging in five spectral ements in soils and rocks emit uniquely bands, the instrument will also take identifiable signatures of energy in the 20-meter (65.6-feet) resolution mea- form of gamma rays. The Gamma Ray surements of the surface to determine Spectrometer looks at these signa- the geological record of past liquid en- tures, or energies, coming from the vironments. More than 15,000 images elements present in the Martian soil. — each 18x18 kilometers (11x11 miles) — will be acquired for Martian By measuring gamma rays coming surface studies. These more detailed from the Martian surface, it is possible data sets will be used in conjunction to calculate how abundant various el- with mineral maps to identify poten- ements are and how they are distrib- tial landing sites for future Mars mis- uted around the planet’s surface. sions. The part of the imaging sys- Gamma rays, emitted from atomic tem that takes pictures in the visible nuclei, show up as sharp emission lines light will be able to show objects about on the instrument’s spectrum. While the size of a house. This resolution will the energy represented in these emis- help fill in the gap between large-scale sions determines which elements are geological images from the Viking orbiters in the 1970s and the very high- resolution images from the currently orbiting Mars Global Surveyor. The THEMIS investigation is led by Arizona State University in Tempe, AZ.

Gamma Ray Spectrometer (GRS) The Gamma Ray Spectrometer will measure the abundance and distribution of about 20 primary elements of the periodic table, including silicon, Gamma Ray Spectrometer Credit: University of Arizona 25 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

present, the intensity of the spectrum and from stars beyond our solar sys- reveals the elements’ concentrations. tem as well. Space radiation can trig- ger cancer and cause damage to the By measuring neutrons, it is possible central nervous system. Similar instru- to calculate the abundance of hydro- ments are flown on the Space Shuttles gen on Mars, thus inferring the pres- and on the International Space Sta- ence of water. The neutron detectors tion (ISS), but none have ever flown are sensitive to concentrations of hy- outside of Earth’s protective magneto- drogen in the upper meter of the sur- sphere, which blocks much of this ra- face. Like a virtual shovel “digging diation from reaching the surface of into” the surface, the spectrometer will our planet. allow scientists to peer into this shallow subsurface of Mars and measure A spectrometer inside the MARIE in- the amount of hydrogen that exists strument will measure the energy from there. Since hydrogen is most likely these sources. As the spacecraft or- present in the form of water ice, the bits Mars, the spectrometer sweeps spectrometer will be able to measure through the sky and measures the ra- directly the amount of permanent diation field. The instrument, with a ground ice and how it changes with 68-degree field of view, is designed to the seasons. GRS is led by the Uni- collect data continuously during versity of Arizona in Tucson, AZ. Odyssey’s cruise from Earth to Mars and while in Martian orbit. Mars Radiation Environment Experiment (MARIE) Led by NASA’s Johnson Space Center in Houston, TX, this science investigation is designed to characterize as- pects of the radiation environment both on the way to Mars and in the Martian orbit. Since space radiation presents an extreme hazard to crews of interplanetary missions, the experiment will attempt to predict antici- pated radiation doses that would be experienced by future astronauts and Mars Radiation Environment Experiment Credit: NASA/Johnson Space Center help determine possible effects of radiation in the Martian environment on human beings.

Space radiation comes from cosmic rays emitted by our local star, the Sun, 26 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

Chapter 5: An Introduction to THEMIS

Of the three instruments on board 2001 Mars Odyssey, the one you will be using is the Thermal Emission Imaging System (THEMIS, pronounced THEE- mis). THEMIS is the second in a series of ASU instruments which are planned for the exploration of Mars. The first, the Thermal Emission Spectrometer, or TES, flew aboard Mars Global Surveyor. The third, a smaller version of TES called, appropriately enough, “Mini-TES”, will fly aboard the Mars Exploration Rovers (MER) in 2003. All use similar principles to explore the Red Planet.

Seeing the Invisible THEMIS is actually composed of two of the spectrum. The THEMIS IR cam- instruments, a thermal infrared (IR) era has detectors sensitive to nine dif- camera and a visual (VIS) camera. ferent wavelengths, or “colors”, of in- You experience infrared radiation ev- frared light. Minerals on and just be- ery day as heat! Each color that we low the surface of Mars receive heat see in a rainbow actually corresponds from the Sun and re-radiate that heat to a specific wavelength or frequency. back into space. The re-radiated heat Red light has a very long wavelength, – infrared light – contains the “signa- while blue light has a very short wave- ture”, composed of specific infrared length. Infrared light has wavelengths “colors”, that allow THEMIS to detect even longer than red light – it’s a color different minerals. By making maps “redder than red”, a color so red your of the different colors received by the eye can’t even see it! The range of all THEMIS IR camera, we can map the wavelengths, which includes the col- minerals on the surface of Mars from ors that your eye can see, is called orbit. the electromagnetic spectrum. The part of the electromagnetic spectrum Both the THEMIS IR and VIS cameras that your eye can see is actually a very tiny slice called the visible spectrum. The part of the spectrum that we call infrared ranges from the edge of the visible spectrum to the start of the radio portion of the spectrum. Yes, radio is nothing more than light! It’s just a color of light so far beyond red that your eye can’t perceive it. Within the visible spectrum there is actually an infinite number of colors, not just the seven we usually give names to. First THEMIS image The same is true of the infrared part Credit: Arizona State University 27 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

are high-resolution. This means that tors such as the position of the Sun or they can see small details on the sur- Mars’ moons must be taken into ac- face of the planet. Each “pixel”, or count. The mission planner is respon- dot that makes up the image, on the sible for looking at the needs of all of IR camera represents an area of 100 these groups and trying to please ev- meters (328 feet) on each side. Thus, eryone! In reality this is often an im- a football field imaged by THEMIS possible task, but the mission planner would take up just a bit more than one tries very hard to make it all fit to- “dot” in the image. The VIS camera, gether. on the other hand, can resolve features as small as 18 meters (65.6 feet) The Principle Investigator for THEMIS on a side. The VIS camera could there- is Dr. Philip Christensen. Dr. fore see things as small as a house – Christensen is responsible for the over- which would appear as a single “dot” all management of the THEMIS project in the VIS image. Each VIS image is and has the ultimate responsibility for of a relatively small area, about 18 x the instrument. Dr. Christensen de- 18 km (11 x 11 miles), roughly the cides what percentage of observations size of a small town. The combina- available will be assigned to which sci- tion of resolution and image size ence teams. That information is given makes the VIS camera an excellent to THEMIS Mission Planner Kelly mapping tool. The Mars Student Im- Bender along with the requests for ob- aging Project will use the VIS camera. servations from the different science teams. Ms. Bender takes these re- Mission Planning quests and schedules them as best as Flying a spacecraft to Mars cannot be possible so that Dr. Christensen’s per- accomplished without a large staff to centages are met and as many of the support it. In the case of Odyssey, the science teams’ observations are made spacecraft itself is managed by as possible. She must also consider Lockeed Martin Astronautics (LMA) in the needs of the two other instruments Denver , CO, under contract to NASA’s on board Odyssey, as well as the needs Jet Propulsion Laboratory (JPL) in of the spacecraft engineers at LMA re- Pasadena, CA. Odyssey carries three garding the positioning of the space- science instruments on board, each of craft. It is not an easy task! which is controlled by a separate team. Each team has its own needs for the Once the mission planner has sched- spacecraft, and these often conflict uled all the observation requests for with other teams or with the needs of the upcoming two-week period, she the LMA engineers. Within each in- writes a small program that transmits strument team are several science the commands to JPL. JPL “packages” teams, each with different priorities for the commands in a format that the observations. In addition, orbital fac- spacecraft can read directly, then 28 MARS STUDENT IMAGING PROJECT RESOURCE MANUAL

passes that information on to LMA in commands are sent from ASU it can Denver. LMA checks to make sure take as much as a day before they there are no commands that will harm travel through the communications the spacecraft or other instruments, pipeline and reach Odyssey. The ob- then passes the commands to the servations can usually be taken in a Deep Space Network (DSN), a system day, and the results are available on of communication dishes spread the third day, if all goes well. Some- around the world that maintain com- times problems with the spacecraft or munication with Odyssey. DSN then with the weather on Mars can delay transmits the commands to the space- observations for as much as a week craft, which, if all was done correctly, or more. Exploring another planet is carries out its new instructions. Once never a routine job! the observations are complete, Odys- sey transmits its data back to DSN on Teachers: Earth and back through the pipeline It is important that you as the stu- to the mission planner. At this point, dents’ MSIP teacher have a general un- THEMIS Data Archivist Kim Murray derstanding of the spacecraft and its processes the data into a form that is mission, capabilities, and constraints, usable by the science teams and hands as this will help you guide your stu- the new images over to them. In ad- dents to choose the most appropriate dition to the two-week lead time re- questions for their research. quired for planning purposes, once the