National Aeronautics and Space Administration

John FL Kennedy Space Center Kennedy Space Center, Florida 32899

Dear Friend of Space

NASA and the Kennedy Space Center welcome your request for information on the national space program. We try to answer all sertous leners, and provide any printed mafler we have on hand that will be useful to you. However, the world-wide interest in space exploration and utilization results in more than 3,000 requests a month arriving at KSC. This volume makes it impossible for us to do special research projects, or anempt to locate materials other than those in the wide variety of brochures, folders, lithographs and booklets that we keep in stock.

About 17 or 18 of our stock iterns of broad interest are preassembled into a "special kit." We also have several subkits, targeted more narrowly to specific subjects such as astronomy, the solar system, Earth's environment, etc. Our experience over many years, in answering hundreds of thousands of requests, indicates that one or another of the items in the special kit will provide the information wanted by most people. We have enclosed one of these special kits tf that will be helpful to you, or substituted or added one or more subkis if they will better serve your needs.

If you have a computer and access to the Internet, you may already be aware of the Lmmense amount of information NASA provides on-line on the World Wide Web. Afew major addresses are listed below, and you can reach many more from the NASA home page. In particular, NASA Spacelink is a huge factual database with sections on current events which are constantly being update. Spacelink provides the istest data on upcoming launches, payloads, happenings within NASA, and space news of general interest. If you do not have access to Internet and the World Wide Web, you can reach Spacelink directly at 205-895-0028. The data format is 8-N-i, and the terminal emulation is VT-i 00.

NASA Spacelink: http://spacelink.msfc.nasa.gov

NASA Home Page: http://www.nasa.gov

Kennedy Space Center Home Page: http://www.ksc.nasa.gov

If you have a satellite dish you can take advantage of the frequent programs on "NASA TV," a channel which provides daily programming as well as special coverage during launches and other major events. The signal is broadcast from GE-2, transponder SC at 85 degrees West longitude, with vertical polarization. Frequency will be on 3880 Megahertz, audio on 6.8 Megahertz.

If you are able to visit the Kennedy Space Center in person, bus tours are available through a concessionaire at a modest charge; MAX movies on a giant screen for which there is also a charge; and many exhibits, movies and programs that are free, as is the parking. Students coming as a group of ten or rnore, with a teacher sponsor, receive discounted rates for both the tour and MAX movies.

Your interest in NASA and the space program is deeply appreciated. We hope that the information in this tefler and the enclosed materials wilt kitfill your needs.

Stee'e Dutczak
Chief, Education Services Branch

The huge Saturn V/Apollo vehicle, Americats most powedul space vehicle, is housed in the 100,000 square foot ApollolSaturn V Center. Visitors can stroll through the plaza area, where they can relive an Apollo launch and witness a lunar landing through dramatic multimedia shows.

For the public

The John F. Kennedy Space Center, commonly called KSC, is located on Merritt Island on the east coast of Florida. The National Aeronautics and Space Administration, or NASA, launches Space Shuttles from kSC. Under the supervision of the U.S. Air Force, Lockheed Martin launches Titan and Atlas vehicles, and McDonnell Douglas launches Deltas, from the adjacent Cape Canaveral Air Station to the east. Both facilities are open for commercial bustours every day of the year except Christmas.

Tours of KSC and Cape Canaveral begin at the official KSC Visitor Complex, on the west side of KSC (see map). Parking is free, as are access to the buildings, the exhibits, and space movies. There is a charge (reduced rates for children under 12) for the bustours, and forseeing the spectacular IMAX movies (one is in 3-D). The Visitor Complex opens at 9:00 a.m., and the first bus tour begins within the hour.

Onyourtourof KSC you will seethe giantVehicle Assembly Building, the Space Shuttle launch pads, the huge Mobile Launch Platforms on which Space Shuttles are assembled, and the ponderous and powerful Crawler-Transporters which haul a Shuttle on its Flatform lo the pad.

The tour of KSC includes delivery to, and return from, the newest visitor aifraction at KSC, the Apollol Saturn V Center. This houses one of the enormous 363-fl tall Saturn V/Apollo vehicles that took astronauts to the Moon, and numerous Apollo Program artifacts andexhibits. Italsoincludesthe New FrontiersGallery and two theater presentations, the Firing Room Theater and the Lunar Surface Theater. These immerse the student in the triumphs and setbacks in the great scientific adventure of landing astronauts on the Moon and returning them safely to Earth.

The separate tour of Cape Canaveral Air Station includes a visit to the Air Force Space Museum. Here you will see early versions of the Delta, Atlas and Titan vehicles which later became the backbone of Unmanned Launch Operations for NASA. It was these vehicles that made the names "Cape Canaveral," or "The Cape," recognized around the world. The Space Museum is built around Launch Complex 26, which displays a Redstone rocket on the pad where America's first satellite, Explorer 1, was launched into orbit by a similar vehicle in 1958. Nearby is Launch Complex 5/6, where astronauts Alan Shepard and Gus Grissom became the first Americans to be launched into space. Check for times when planning to take this tour.

Bus tours run until about two hours before dark. Photography is allowed throughout the Visitor Complex and on the bus tour. If you do not have a camera they are available for loan, without charge (identification required), or disposable cameras may be purchased at the Space Shop. The user must provide the film, also available in the Space Shop.

Professional educators are invited to visit the Educators Resource Center (ERC), located in the Center for Space Education in the northwest corner of the Visitor Complex- The ERC has extensive facilities to aid the teacher in the preparation of aerospace- related teaching materials. These include a large number of free aerospace publications, and 35mm slides, videotapes and text data that can be copied on-site.

Exploration Station, the hands-on minds-on student science center, is also located in the Center for Space Education. It has two auditoriums, one devoted to lectures and science demonstrations and a second science activities room, open to everyone from 9:OOto5:00. Teachers and othergroupsponsors should call 407-867-2959 for reservations.

The building immediately in front of the parking lot is Spaceport Central, which has a large number of fascinating and informative exhibits. The information counter, where one can obtain current schedules and free maps, is inside this building. Free guided tours are offered periodically throughout the day. These will helpyou understand the meaning ofwhat you see- from communications satellite displays to models of the huqe launch facilities you may see later on your bus tour. The free space theater is located here.

North of Spaceport Central is the Gallery of Space Flight, whereyou can see real Mercury, Gemini and Apollo spacecraft. They were recovered after their missions and brought here, to be preserved as pantofournational history.Theexhibits inthis building provide a fascinating look at the early days of the American manned space flight program.

West of Spaceport Central, a stroll through the Rocket Garden takes you from the comparatively tiny Mercury/Redstone that lifted the first American into space, to the huge Saturn lB vehicle. This Saturn launched three-man Apollo crews into Earth orbit during the Apollo, Skylab, and Apollo-Soyuz Test Project programs. The Shuttle Plaza, on the eastside of the Visitor Complex, contains a full-size model of a Shuttle orbiter, which may be entered by visitors. It provides a realistically detailed look at the cargo bay, living quarters and cockpit of an orbiter. Nearby are two of the giant solid rocket boosters and external tank that provide the brute power to lift a Space Shuttle toward orbit.

The Galaxy Center is on the north side of the Visitor Complex. Admission is free, but there is a charge to attend the two giant IMAX theaters. Three movies are available: check at the Information Counter for time and theater. With IMAX, a complex camera system projects to a curved screen 50 feet high and 70 feet wide. The breathtaking imagery is supported by a six-track stereo sound system. Attending an MAX movie is very much actually being there during the sound and fury of a Space Shuttle liftoff, or working with space-suited astronauts in the vast openness and sometimes eerie silences of space.

The NASA Art Gallery, a large group of paintings by well-known artists depicting various aspects of the history of space flight, is located at the east end and along the walls of the Galaxy Center. This unique collection is a must-see item for fans of space art. There are also many other exhibits located throughout the hallways. And a huge memorial to astronauts who died in the line of duty is located directly north of the building.

Finally, you can browse through the large variety of models and souvenirs for sale in the Space Shop, or eat lunch at the Orbit Cafeteria or MILA's Roadhouse. There are also fast food, ice cream and snack stands available

We recommend that you plan to spend a day visiting KSC. Here, on the threshold of space, each visitor has the opportunity to gain a new appreciation of the past, present and future of the "space age" in which we live.

The tour of Launch Complex 39 includes a drive past Pad 39A, one of two pads at KSC capable of launching Space ShuWe vehicles. A mound located between Fads A and B provides visitors with a good vantage point from which to photograph both launch sites.

Facilities and activities

The 140,000-acre John F. Kennedy Space Center is the major launch site for the National Aeronautics and Space Administration (NASA).

Prior to the Space Shuttle era, manned launches from KSC included the Apollo missions, which landed men on the Moon; three flights to Skylab, the first United States space station; and the Apollo/ Soyuz Test Project mission.

NASA also has launched a wide variety of unmanned spacecraft, using expendable rockets, lifting off from Cape Canaveral and from Vandenberg Air Force Base in California. These have included weather and communications satellites, orbiting scientific satellites, lunar explorers and landers, and interplanetary probes to Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune.

Except for operational areas, the KSC reservation is designated as a national wildlife refuge. The Canaveral National Seashore lies within the refuge area. Both are open to the public during daylight hours exceptwhen tests on the pad or launch preparations are in progress.

There are recreational beaches east of Titusville and New Smyrna Beach, and nature study trails on the refuge. Information is available at facilities located east of Titusville on State Road 402.

Through an agreementwith the U.S. Air Force, NASA uses many facilities on Cape Canaveral, including several it has built there. The 5,000-mile- long Air Force Eastern Test flange supports NASA, as well as Air Force launches.

The KSC Visitor Complex can be reached by vehicles coming from the north, south or west (see map). State Road 405 leads directly onto the NASA Causeway, on which the facility is located. State Road 405 can be reached from Interstate 95, U.S. 1, or the north branch (State Road 407) of the Beeline Expressway (State Road 528). The latter leads south of Orlando to the Disney World area. State Road 3, which intersects NASA Causeway east of KSC Visitor Complex provides an alternate route from the south.

A Versatile Vehicle

The first true aerospace vehicle, the Space Shuttle, takes ofi like a rocket. The winged orbiter then maneuvers around the Earth, like a spaceship, and lands on a runway like an airplanet.

The Space Shuttle is designed to carry large and heavy payloads into Earth orbit. But unlike earlier manned spacecraft, which were good for only one flight, the Shuttle orbiter and solid rocket boosters can be used again and again.

The Shuttle also provides a new capability, to repair or service spacecraft in orbit, or return them to Earth for a more extensive overhaul and another launch.The Long Duration Exposure Facility (LOEF), a tree-flying payload, remained in orbit almost six years before it was recovered and returned to Earth, where it yielded a wealth of new data on the space environment. An INTELSAT commercial communi cations satellite stranded in a useless orbit was re trieved in dramatic fashion by Shuttle astronauts, re paired and then re-boosted to its proper orbit to be gin operation. The Hubble Space Telescope is suc cessfully serviced in orbit and has helped unlock a

many of the mysteries of the universe since the re pairs and improvements were made.

Satellites today play a major role in the fields of environmental protection, energy, weather forecast ing, navigation, fishing, farming, mapping, oceanog raphy and many other space-borne applications. Sat ellites also provide worldwide communications, link ing the people and nations of the world together A single channel on many communications satellites, can provide television coverage to most entire na tions. Satellites have become an indispensable part of the modern world.

All satellites released from a Space Shuttle ini tially enter low Earth orbit - about 115 to 250 miles(1 85-402 kilometers) altitude. Some, such as Hubble or the environment-monitoring Upper Atmo sphere Research Satellite, remain there throughout their working lives.

Many spacecraft, such as the weather and com munications satellites that can "see" a third of the world at once, operate at a much higher level known as geosynchronous orbit. This is a flight path about 22,300 miles (35,888 kilometers) above and aligned with the equator, with a speed in orbit that matches that of the Earth's surface below. From the ground such satellites appear to hang motionless in the sky. Spacecraft reach this altitude by firing an attached propulsion unit, such as an Inertial Upper Stage (IUS), or the smaller Payload Assist Module (PAM), after deployment from the Shuttle orbiter. At altitude an on-board engine fires to tircularize" the orbit.

Sometimes interplanetary explorers, such as the Magellan mission to Venus or the Galileo mission to Jupiter, are launched from the Space Shuttle. They also use the US to exit Earth orbit and begin their journey to Earth's planetary neighbors.

The ability of the Shuttle to land on a runway, unlike the expensive parachute descent and recov ery at sea techniques used in the Mercury, Gemini and Apollo human spaceflight programs, saves both time and money. In addition, again unlike prior manned spacecrafi, the most expensive Shuttle corn ponents can be refurbished and made ready for an other launch. The complex and expensive orbiter is designed to last 100 flights minimum, and the solid rocket booster casings, engine nozzles, parachutes, etc., for 20 launches. Only the external tank is ex pended on each flight. The high cargo capacity and major component reusability of the Shuttle make it unique among space vehicles.

The orbiter is the only part of the Space Shuttle which has a name in addition to a part number. The first orbiter built was the Enterprise, which was de signed for flight tests in the atmosphere rather than operations in space. It is now at the Smithsonian Mu seum at Dulles Airport outside Washington, D.C. Five operational orbiters were built: (in order) Columbia, Challenger (lost in an accident Jan.28, 1986), Discovery.

The orbiter Columbia returns to Kennedy's Shuffle Landing Facility completing Mission STS-62 on March 18,1994. All four orbiters in the Shuffle fleet are now equipped with a drag chute that is deployed during landing to assist in stop ping and to provide greater stability in the event ota flat tfre or steering problem.

Discovery, Atlantis and Endeavour (Challenger's re placement).

The Parts of the Space Shuttle

The flight components of the Space Shuttle are two solid rocket boosters, an external tank and a winged orbiter. The assembled Shuttle weighs about 4.5 million pounds (2.041 million kilograms) at liftofl.

The orbiter carries the crew and payload. It is 122 feet (37 meters) long and 57 feet (17 meters) high, has a wingspan of 78 feet (24 meters), and weighs from 168,000 to 175,000 pounds (76,000 to 79,000 kilograms) empty. It is about the size and gen eral shape of a DC-s commercial jet airplane. Orbit ers may vary slightly from unit to unit.

The orbiter carries its cargo in a cavernous pay- load bay 60 feet (18.3 meters) long and 15 feet (4.6 meters) wide. The bay is flexible enough to provide accommodations for unmanned spacecraft in a vari ety of shapes and sizes, and for fully equipped sci entific laboratories such as the Spacelab or SPACEHAB. Depending on the requirements of the particular mission, a Space Shuttle can carry about 37,800 pounds (17,146 kilograms) into orbit,

An orbiter is equipped for flight with three main engines, each producing 400,500 pounds (1.781 mil lion newtons) of thrust when operating at 104 per cent at liftofl (at sea level). This figure is derived from flight experience and is about 2.7 percent better than the required design minimum. The engines burn for over eight minutes, while together drawing 64,000 gallons (242,240 liters) of propellants each minute when at full power

The orbiter is mated to the huge external tank, standing 154 feet (47 meters) long and 28 feet (8.5 meters) in diameter. The tank weighs a total of 1.68

The Shuffle's usefulness as a platform for on-orbit servic ing of spacecraft was demonstrated during the STS-61 HattIe servicing mission in 1993. Spacewalking astronauts successfully corn pleted repairs and upgrades to the Hubble telescope whfle it was temporanly stored in the orbiter Endeavour's payload bay

million pounds (762,048 kilograms) at liftoff. Two in ner tanks provide a maximum of 145,000 gallons (548,825 liters) of liquid oxygen and 390,000 gallons (1,476,150 liters) of liquid hydrogen. The tank feeds these propellants to the main engines of the orbiter throughout the ascent into orbit, and is then dis carded.

Most of the Shuffle's power at liftoff is provided by its two solid rocket boosters. Each booster is 149.1 feet (45.4 meters) high and 12.2 feet (3.7 meters) in diameter, and each weighs 1.3 million pounds (590,200 'kilograms). Their solid propellant consists of a mixture of aluminum powder as the fuel, alumi num perchlorate as the oxidizer and iron oxide as a catalyst, all held together by a polymer binder. Flight experience indicates they produce about 2.908 mil lion pounds (12.935 million newtons) of thrust each for the first few seconds after ignition, before gradu ally declining for the remainderof a two-minute burn. Together with the orbiter's three main engines firing at 104 percent, total thrust of the Space Shuffle at liftoff is 7.0175 million pounds (31.2 million newtons).

In-orbit maneuvering capability is provided by two smaller Orbital Maneuvering System (OMS) en gines located on the orbiter. They burn nitrogen tetroxide as the oxidizer and monomethyl hydrazine as the fuel, from on-board tanks carried in two pods at the upper rear, The aMS engines are used for major maneuvers in orbit, and to slow the vehicle for re-entiy at the end of the mission.

Crew Accommodations

Nominal crew size for a Shuttle flight is up to seven people; 10 could be carried in an emergency. The crew occupies a two-level cabin at the forward end of the orbiter. They operate the vehicle from the upper level, the flight deck, with the flight controls for the mission commander and pilot located in the front. A station at the rear, overlooking the payload bay through two windows, contains the controls a mis sion specialist astronaut uses to operate the Remote Manipulator System arm which handles elements in the payload bay. Mission operations displays and controls are on the right side of the cabin, and pay load controls on the left. The latter are often oper ated by payload specialists, who are usually not ca reer NASA astronauts. The living, eating and sleep ing area for off-duty crew members, called the 51-F ON-ORBIT 1965 - KSC Center Director Roy D. Jr. served as pilot durinQ the only abon-to-orbit in Shuffle history He said that he hopes he aiways retains the inernory of what it was like to be a payload' during such a precipitous mornent, but also noted that the incident showed the NASA can-do spirit at its best₁ as the mission was coin pieted successfully and even allowed time for lighter moments.

Middeck is located below the flight deck. It contains pm-packaged food, a toilet, bunks and other arneni ties. Experiments for the flight also may be stowed in middeck lockers.

A typical Shunle crew includes a commander and pilot, mission specialists and sometimes payload specialists. The commander and pilot are selected Iron' the pilot astronaut corps, highly qualified individuals with at least 1,000 hours pilot-in-command time In jet aircraft who also must meet other rigorous qualifica tions. Mission specialists are scientists, physicians or other highly qualified specialists.

Payload specialists are persons other than NASA astronauts - including foreign citizens - who have specialized onboard duties. They may be added to Shuttle crews if activities that have unique require ments are involved.

Shuttle crews experience a designed maximum gravity load of 39 during launch, and less than 1 Sq during re-entry. These accelerations are about one- third the levels experienced on previous U.S. human spaceflights. Many other features of the Space Shuttle, such as a standard sea-level atmosphere, make spaceflight more comfortable for the astronaut.

Typical Shuttle Mission

The rotation of the Earth has a significant effect on the payload capabilities of the Space Shuttle. A due east launch from the Kennedy Space Center in Florida uses the Earth's rotation as a launch assist, since the ground is turning to the east at that point at a speed of 915 miles (1,473 kilometers) per hour.

Spacecraft and other payload items arrive at the Kennedy Space Center and are assembled and checked out in special buildings before being loaded into the orbiter. Each Shuttle arrives as a set of com ponent parts. The solid rocket booster propellant seg ments are received and checked out in a special fa cility, then taken to the Vehicle Assembly Building (VAB) and stacked on a mobile launcher platform to form two complete rockets. The external tank is re ceived and prepared for flight in the VAB, then mated to the solid rockets. An orbiter is checked out in the Orbiter Processing Facility, then moved to the VAB and attached to the external tank. A giant crawler- transporter picks up the mobile launcher platform and the assembled Shuttle and takes them to the pad. The Shuttle remains on the platform until liftoff.

The orbiter's main engines ignite first and build to full power before the huge solid rockets ignite and liftoff occurs. The solid rockets burn out after about two minutes, are separated from the tank, and para

chute into the ocean about 160 miles (258 kilome ters) from the launch site. Two special recovery ships pull the parachutes out of the water and tow the rocket casings to land, where they are refurbished and sent back to the manufacturer to be refilled with propellant.

The orbiter continues into space - a total of over eight minutes of burn-time on the three main engines - and then separates from the external tank. The latter breaks up as it re-enters the atmo sphere over an uninhabited area.

On most missions the orbiter enters an elliptical orbit, then coasts around the Earth to the opposite side.The OMS engines then fire long enough to sta bilize and circularize the orbit. On some missions the OMS engines also are fired soon after the exter nal tank separates if more velocity is needed to reach the desired altitude for the burn that circularizes the orbit. Later OMS burns can raise or adjust this orbit, if required by the needs of the mission. A typical Shuttle flight lasts about ten days, but modifications now being performed will enable some orbiters to stay in space for up to 16 days.

After completing mission objectives, which might include deploying a spacecraft, operating onboard scientific instruments or conducting experiments, the orbiter re-enters the atmosphere and lands. Kennedy Space Center is considered the prime end-of-mis sion landing site, while Edwards Air Force Base, Calif., is the alternate. Unlike prior crewed space craft, which followed a ballistic trajectory upon re entry, the orbiter has a cross range capability (can move to the right or left off the straight line of its entry path) of about 1,270 miles (2,045 kilometers). The landing speed is from about 212 to 226 miles (341 to 364 kilometers) per hour. The orbiter is im mediately "safed" by a ground crew with special equipment, the first step in the process which will result in another launch of this particular orbiter.

Spacelab and SPACEHAB:

Science in Orbit

Periodically the Shuttle is scheduled to carry a complete scientific laboratory into Earth orbit. Two configurations are available, the Spacelab and the SPACEHAB. These modules are similar to a small but well-equipped laboratory on Earth, but designed for zero-gravity operation. They provide a shirt-sleeve, pressurized environment where crew members can penform scientific tests utilizing the high vacuum and microgravity of orbital space. They also can make astronomical observations above the Earth's obscur ing atmosphere.

Two complete Spacelabs (plus instrument-car rying platforms exposed to space, called "pallets") have been built by the European Space Agency (ESA), which paid for the development expense and manufacturing costs of the first one. NASA purchased the second unit.

Spacelab experiments for a particular mission may be sponsored andlor organized by a nation, such as the German D-1 and D-2 flights and the Spacelab J mission jointly sponsored by Japan and NASA. Or they may be oriented around a particular field, such as the Spacelab Life Sciences-i and -2 missions which focused on life science research in microgravity. Sometimes Spacelab flies as an all-pallet configura tion, where all the instruments are exposed to space and operated from inside the orbiter.

The SPACEHAB module was commercially de veloped by McDonnell Douglas Aerospace-Huntsville, under contract to SPACEHAB, Inc. The module of fers up to 61 standard lockers, such as those found

During the first untethered space walk in 10 years, Mission Specialist Mark Lee tests the new Simplified Aid for Extra vehicular Rescue (SA~ER) system. The 28th space walk of the Shuttle program took place on Mission STS-64 in September 1994.

in the orbiter rniddeck, and two single or double racks for experiments~ In addition, there is access to the exterior of the module for experiments requiring ox posure to the space environment. Tvvo SPACEHAB rnodu les have been built.

The Spacelab or SPACEIHAB remain in the or biter payload bay throughout the mission. After land ing, the laboratory is removed and preparations be- gin to eanfigure it for its next flight.

Exploring Mars

Sublect: Planetary Science
Topic: Mars

Why EXPLORE MARS? Why would we explore Mars, the fourth planet from the Sun, the next outward from
the Earth? What is there for humankind? Through a telescope, Mars' red light reveals little detail, an
orange round world splashed with gray, white at its poles, rarely obscured by clouds. Close up, Mars is stunning: clouds hover ing above lava-draped volcanos; nearly endless chasms, their depths lost in mist; towering ice cliffs striped with red. Mars' past is laid bare in the landscape: impact scars mark world-jarring collisions with asteroids, and deep winding channels recall titanic floods. But robot eyes alone have seen these sights, and then only from orbit high above.
We will find water. Mars is the only planet besides Earth that was ever cut by flowing water or graced by lakes and ponds. Now, that water is frozen at the poles and buried beneath Mars' frigid deserts. In those ancient martian pools, might life have sprung up and prospered? The pools are dry and sterile today, but could life persist in deep and hidden places? Someday, will humans walk those distant deserts, seel:ing signs of ancient life?

A HISTORY OF EXPLORATION

Humans have known of Mars since before re corded history. Even 3600 years ago the Babylonians wrote about Mars looping motion across the sky and changing brightness.
·Mars was one of five "stars that wandered" among the fixed stars of the night, and was special because of its color: red. In ancient India, Mars appeared like a fire in the sky-for many other cultures, its redness recalled the fire and blood of war. In ancient Greece, the red wanderer personified the god of war, "Ares."
When the Romans conquered Greece, they adopted this symbol ism arid named the planet for their god of war, "Mars."
Through the Middle ages, astrologers studied Mars' motions to help them predict the future-if Mars moved unfavorably, wars would be lost! But no one could predict Mars' motion accurately, even using Copernicus' theory (of 1543) that the planets orbit in circles around the Sun. Johannes Kepler solved this puzzle in 1609 when he discovered that Mars orbits the Sun in an ellipse, not a circle. Seventy~five years later, Kepler's solution was crucial to Isaac Newton's study of gravity.
While Kepler explained its oibit, Galileo Galilei transformed Mars into a world. In 1609, Galileo first viewed Mars through his newly invented telescope. Although his telescope was no better than a modern toy, it revealed enough to prove that Mars was a large sphere, a world like the Earth. Could this new world be inhabited? As telescopes improved, more of Mars could be seen:
polar icecaps, color patterns on its face, clouds, and hazes. These observations all fit a habitable planet, and speculations that Mars was, inhabited became more and more believable.
The idea of living mattians came to full flower in 1877 when the Italian astronomer Giovanni Schiaparelli observed thin dark lines crossing Mars' bright "continents." He called the lines "canali," "channels" in Italian, and the word was widely misread as "canals." In the U.S., Percival Lowell seized on the canals as proof of a martian civilization, advanced enough to move water across a whole world. Many scientists agreed. but most thought that the canals were optical illusions. They thought that Mars was too cold and its air too thin for life as we know it.
Understariding of Mars advanced little from Lowell's time in the late nineteenth century until 1965, when theMariner4 spacecraitfiew within 10,OOOkilometersofthe nirtian surface. Its pictures, (he frrst close-up views of Mars, showed a Moonlike landscape of plains pocked by impact craters. There were no canals or other signs of life. Mariner 4 finally proved that Mars atmosphere, only 0.7% as thick as the Earth's, was much too thin for life as we know it.
Four years later the twin spacecraft Mariner 6 and Mari ncr 7 flew by Mars again, carrying cameras and spectrometers to measure the temperature of Mars' surface and the composition of its atmosphere. Their photos again showed no canals or other signs of life, but did reveal a volcano, plains without impact craters, and areas of unusual hummocky (chaotic) terrain. Mars mass and density were calculated from spacecraft tracking. The spectrometers showed that Mars was very cold (-123⁰C at the south pole), and that Mars' thin atmosphere was almost ail carbon dioxide. At the time, Apollo il's landing on the Moon overshadowed the successes of Mariners 6 and 7.
Exciting as they were, the early Mariners only spent a short time near Mars as they flew past; more time was, needed, and that meant going into orbit. So in 1971, Mariner 9 arrived at Mars and became the first artificial object ever to orbit another planet. More than twice as big as its predecessors, Mariner 9 carried color cameras and new instruments tailored to investigating Mars' surface and atmosphere. An unsung part of the spacecraft was its computer system. which allowed Mariner 9 to wait until Mars' atmosphere cleared ofa planetwide dust storm. Mariner 9 operated for almost a year, mapped 85% of Mars' surface in more than 7000 images, analyzed Mars' gravity field, measured surface temperatures and dust abundances, and measured temperatures and humidity of its atmosphere.
Mariner 9's view of Mars was the first detailed global view of another planet; it revealed a "New Mars," unlike any earlier concept. The earlier Mariners saw land typical of the southern
hemisphere: craters and more craters. Mariner 9 saw what they missed. First, the Valles Mannens, a canyon up to 100 kilometers wide and 10 kilometers deep that would reach from Los Angeles to New York! Giant valleys extend from the Valles and elsewhere, mute testimony to devastating floods in Mars' distant past. Most of the valleys end in the noithern plains, a vast lowland encom passing alinost a third of the planet. There, the floodwaters ponded into huge lakes or even an ocean. Signs of water ap peared in the southern highlands too, for the most part as small valleys draining away from the largest craters and uplands. Despite these signs of ancient water, Mars now is too cold and its atmosphere too thin for liquid water to remain.
Mariner 9 also was the first to see Mars' volcanos, the biggest in the solar system. The biggest of all, Olympus Mons, is 600 kilometers across at its base and 25 kilometers tall. Smaller volcanos and lava flows appear all over Mars, especially on the Tharsis l:::ise, a huge bulge distorting Mars' spherical shape. Looking toward space, Mariner 9 took the first close-up images of Mars' moons, Phobos and Deimos. They are linle more than large potato-shaped rocks, about 10 kilometers long, and appear similar to asteroids.
Mariner 9's global perspective and spectacular images of water-carved landscapes inspired further exploration of Mars to focus on the search for life. Mter extensive development, the twin spacecraft Viking 1 and 2 were launched in 1975 and entered Mars orbit in 1976. Each ~'ng was actually two spacecract: an orbiter and a lander Each orbiter had a pair of cameras and instruments for mapping surface temperature and atmosphere humidity. Each lander included a weather station, a seismometer for detecting "marsquakes," instruments for analyzing soil, and a stereo TV camera.
The Viking I lander touched down gently on July20, 1976, on Chryse Planitia in the northern lowlands. Its robot eyes took the first photos of the martian surface: a rolling desolation of dark rounded rocks and brick-red dust under a pink sky. The rocb~m probably volcanic, pined and smoothed by eons of blowiq sands. On landing, though, the winds were light, at rmnttU kilometers per hour Viking 1 sits at a latitude corn-ban the Sahara Desert on Earth, but its daytime temper*umsduhed to a high of-10⁰C, and dropped to a numbing -90⁰C before sunrise.

WHY CONTINUE?

Isthere any reason to continue exploring Mars? Haven't we ilearned everything already? Telescope and spacecraft explora tion have taught us a lot, but many important questions remain unanswered.
For instance, why is Mars' surface (with many craters and huge volcanos, and no continents) different from the Earth's surface (with continents and chains of smaller volcanos, but few craters)? The answer seems to lie deep within the planets, where hot rock flows slowly upward toward the surface. This motion is called mantle convection, and it seems to take different forms on the Earth and Mars. On the Earth, mantle convection moves large pieces of the surface, the geologic plates, and most volcanos, earthquakes, and mountains form at plate boundaries. On Mars, however, the upward flow of mantle rock bows up the surface but doesn't break it into pieces. The upward flow is centered at Tharsis, a bulge or high plateau about 4000 kilometers across and up to 10 kilometers high. Tharsis is covered by volcanos that reach even higher; Olympus Mons is 25 kilometers tall. It appears that the volcanos on Tharsis have erupted for almost the whole history of Mars. The Tharsis volcanos might still be active but dormant - no volcano eruptions have ever been seen. Around Tharsis are many long cracks (including the Valles Marineris), showing that the martian crust was stretched and broken as Tharsis swelled. The high elevations, volcanos, and cracks were all caused by mantle convection. But compare this stable pattern with the Earth, where mantle convection produces chains of volcanos and long mountain ranges that come and go through time.
Another question: Why doesn't Mars have oceans like the Earth does? Mars' atmosphere is now too thin and its temperature too cold to allow liquid water But the important questions are


THE FUTURE
about water itself - how much water does Mars have, and where is it? Mars certainly had surface water and groundwater once; only liquid water could have shaped the valley networks in the highlands and the huge flood channels that cut from the high lands to the northern lowlands. But how much water was there? Estimates range from the equivalent ofan ocean 10 meters deep covering the whole surface to the equivalent ofa layer kilometers deep. The first is not much water at all, and the second is a lot of water! However much water there was, it is not now on the surface, except for a bit in the polar icecaps. Where did the water go? It could be underground in pools of groundwater, either small or huge depending on how much water Mars started with. Or it could have escaped to space and been lost completely - the hydrogen from water can escape easily through Mars' low gravity and sraall magnetic field.
And finally, we don't know if there is or was life on Mars. There are no canals or ancient cities, and no clear signs of any life on Mars' inhospitable surface. Bat Mars' climate was mild once, with a thicker atmosphere, flowing water, open lakes, and perhaps even an ocean. Life on Earth may have started under similar conditions, possibly at underwater hot springs. With its volcanos and lava flows, Mars probably also had hot springs - if Mars had oceans or lakes, could life have also started on Mars? We know about the origins and history of life on Earth from fossils - how and where would we look for fossils on Mars? And why confine our search to Mars' surface? On Earth, many kinds of bacteria live deep inside rocks, and die when exposed to light and fresh air Could organisms like these be alive and prospering in groundwater far beneath the surface of Mars? And do we now have fossils of these bacteria, preserved for eons in the martian meteorites?
Some of these important questions about Mars may be answered in the next few years by robotic spacecraft.
Mars Pathfinder, the first Mars lander since Viking 2, was launched in December1996. It will land in 1997, nestled among four airbags to cushion its fall. After landing, Pathfinder will open like a three-petal flower; each petal is a solar cell panel. The spacecraft body, among the petals, will contain the computer control and communications system. Above the body will rise a camera system, which will take full-color stereo pictures of the landing site. The camera is also sensitive to infrared light, which will help determine what kinds of rocks and soils are there. Instruments to measure wind speed, temperature, and pressure will stand on a rod above a petal.
Pathfinder carries a small rover, named Sojourner, that will drive off a petal soon after landing. The rover is only 65 centime ters long and weighs only 10 kilograms. It will travel slowly. avoiding big rocks and holes with its stereo camera and computer "hazard avoidance system." Also on board are a close-up camera and a chemical analyzer, which are essential for understanding the soils and rocks that Sojourner meets.
The Mars Global Surveyor spacecraft was also launched in 1996 to orbit Mars, and reflies many of the science instruments on the lost Mars Observer spacecraft. To provide global weather coverage and detailed images of the surface, Mars
Global Surveyor will carry a color camera. With its telephoto tens, objects as small as 2 meters should be visible; we might see the Viking landers or their shadows! Mars Global Surveyor will measure elevations by bouncing laser light from the spacecraft off of Mars' surface, and measuring how long it takes the tight to return to the spacecraft; there are stitl questions about the heights of volcanos and the depths of the chasms. Temperatures on Mars' surface will be mapped by a thermal spectrometer; will it find hot spots from active volcanos, geysers, or springs? The thermal spectrometer will also map out the distribution of minerals and rocks on Mars. Variations in Mars' gravity will be mapped from changes in the spacecraft's speed; this subtle measurement helps locate heavy and light rock masses beneath Mars' surface. A magnetometer will determine whether Mars has its own internal magnetic field, like the Earth does.
Space exploration is a challenging and complex endeavor. The Russian-led international Mars 96 spacecraft was alsolaunched in November 1996, but it failed U.S. MARS MISSIONS UCCESSFUL AND PLANNED.

MISSION LAUNCH ARRIVAL HIGHLIGHTS
Mariner 4 Nov.28, July 14, 1965 22 black and white images of deso
flyby 1964 late, cratered southern hemisphere.
No canals or signs of life. Water frost
e seen. Proof that Mars' atmosphere is
very thin. Mariner 6 and 7 Feb.24 and July 31 and 75 and 126 black-and-white images of
Flybys Mar. 27, 1969 Aug. 5,1969 equatoriat region, sombern hemi
sphere, and south polar ice. Measured
Mars' mass and density.
Mariner9 May30. 1971 Orbit: Nov.14, 7329images,maayin colon Global
Orbiter 1971 maps ofelevation, temperature. First
views of ~ge volcanos of Tharsis,
chasms of Valles Marineris, water-cut channels, Mars' moons.
Viking I Aug.20, Orbit: J~e 19, Orbiter gives >30,000 images of
Orbiter, 1975 1976 sutface, many in color. Global maps of
Lander Landing: Lly 20, temperature, atmosphere water
1976 content, surface properties. laauder
gives first images from Mars' surface:
dark nocks, ned dust, pink sky. Tests
soil for ffe and finds none.
Records Mars weather.Vll'ing 2 Sept. 9, Orbit: Aug. 7,Orbiter, 1975 1976
Lander Landing: Sept. 3,1976 Like Viking 1, Orbiter gives >20,000 images of surface. Lander finds no life: again dark rocks, ned dust, pink sky. Records Mars weather
Mars Global Nov. 7, Planned for Global weather imagery, surface top orveyor, 1996 Sept.1997 graphy and temperatures.
Orbiter Mars Pathfinder Dec. 4, Planned for Landing in Ares Valles; engineenng
Lander 1996 July 4,1997 tests, imaging and chemical investiga
tions. Mars Surveyor Planned for Global imagery, atmospheric tempera-
Orbiter 1998 Dec. 1998 tore profiles. Mars Surveyor Planned; First landing near martian poles.
Lander 1998 Jan. 1999 to escape Earth's gravitational pull because of a rocket malfunction. All its scientific instruments, including an orbiter, two penetrators, and two small landers, were lost.
In a few years, even more spacecraft will be headed toward Mars. Next in line are the Mars Surveyor 98 Orbiter and Lander, slated for launches in late 1998 and early 1999. The 98 Orbiter will fly a new lightweight color camera for weather and surface images. Its other instrument will be a complex detector for infrared light, which will give temperatures and pressures throughout the atmosphere. The 98 Lander will be the first mission to the martian poles, where it will descend onto deposits of dusty ice. The Lander will carry' cameras, a robot arm with a scoop, a chemical analyzer, and weaQier instrttrnents. Beyond 1998, missions to Mars are planned for every opportunity (every two years); many will be collabora tions with other countries. The missions might include networks of weather and "marsquake" stations, a landing in an ancient lakebed or in the Vatles Marineris, a search for groundwater using radar, or a return of martian samples to Earth!
When will humans explore Mars? No space agency has serious plans for hun'an landings on Mars in the near future; landings before 2020 are probably impossible. But someday, people wilt descend from a spacecraft, stand on red soil, and see for themselves the canyons, volcanos, and dried lakebeds of Mars.
For exploring Mars, it is important to know which events happened in which order, and which areas are older than others. A simple way of figuring out the sequence of events is superposition-most of the time, younger things are on top of older things. and younger (more recent) events affect older things.
Ia. Supe'position in your lije. Is there a pile of stuff on your desk? On your teacher's? On a table or the floor at home? Where in the pile is the thing you used most recently? The thing next most recently? Where in the pile would you look for something you put down 10 minutes ago? When was the last time you (your teacher or your parent) used the things at the bottom of the pile? Using superposition, we can sort out many of the complicated events in the history of Mars. For example. you can sort out all the events that affected the area of Pig. 1, which shows a small part of the wall of the great canyon system of Valles Marineris. Toward the top of the picture is a high plateau (labeled "P" on the picture), with a large circular impact
crater ("C"). It formed when a huge meteorite hit Mars' surface. Below the plateau is the wall of Valles Marineris. Here, the wall has been cut away by huge landslides ("L"), which leave bumpy rough land at the base of the wall and a thin, bmad fan of dirt spreading out into the canyon floor. In the canyon wall, almost at its top, alternating layers of light and dark rock are exposed.
To discover the history ofthispartoftheVallesMarineris, start by listing all the landscape features you can see, and the events that caused them (don't bother listing every small crater by itself). Now list the events in order from oldest to youngest. [Ilints: How naany separate landslides are there? Is the large crater ("C") younger than the landslides? Are the landslides younger than the rock layers at the top of the walls? Are the small craters older or younger than the landslides?] Sometimes, you cannot tell which of two events was younger What additional information would help you tell? To learn more about this image, visit the Internet site: http://cass.jsc.nasa.gov/education/k12/gangis/mars.html

These locations, on Mars, were considered as possible landing sites for the Viking missions.

2a. if martians sent spacecraft to these same latitudes and longitudes on Earth, what would they find? Would they fmd life or an advanced civilization?
2b. If you were a martian, why would you explore the Earth?
Does Earth have resources you might need? What would you
want to know about the Earth? Where would you land first?
(From B. M. French, The Wling Discoveries, NASA EP-146, OcL
1~n)
Fig. 1. Craters and landslides at the wall of Valles Marineris. Viewed at an angle, scene is 60 kilometers across.

Activity 3: ~pd Craters, More or Less

When large meteorites strike a planet's surface, they leave impact craters. Meteor Crater in Arizona is the most
famous of the 150 impact craters Imown on Earth. During a meteorite impact. rocks from deep in a planet are gouged up and thrown onto the surface, so impact craters can be used like a mine or drill hole to show us rocks from underground. Also, the abundance of impact craters on a surface shows its age-the more craters on a surface, the older it must be.
3a. Crater Excavaflons: Laboratory Experiment. Start with a flat sand surface: A playground sandbox is ideal, but any unbreakable box with a surface bigger than about 2' x 2' will do. Smooth the sand surface, and cover the sand with a layer of fine, contrasting powder: different sand, tempera paint powder, or colored sugar work well. Cover this layer with about a few millimeters of sand. Then throw marbles or gravel into the sand, and see if your crater can excavate the contrasting layer How deep is your crater? How far was the contrasting powder thrown by the impact? This experiment can be expanded and quantified by experiments with different types of sand. different depths of burial, marbles of different sizes and weights, and different angles of impact. Using a slingshot to shoot the marbles will perrrnt
.1 impacts and bigger craters, but careful supervision is required.
Sb. Craters old and New: Inbora tory Experiment Make many craters on a smoothed sand surface by throwing gravel or marbles until the sand is evenly peppered with craters. Then smooth out half the sand surface, erasing all its craters. Resume throwing gravel or marbles at the sand, but only throw about
I
half as many as before. Now, half the sand surface should be heavily cratered and the other half moderately cratered. If you hadn't seen it happen, could you tell which part of the sandbox was smoothed during the experiment?
3c. Resurfacing-Some Thought Questions. Many processes on planets can erase, or smooth out, earlier landscapes. The word for this is resurfacing, literally putting a new surface on the land. What processes on Earth act to resurface its land? Compare Fig. 2 with a map or aerial photo of a place you know-why does Mars have more craters than your place? Find a globe or map of the Moon-what resurfacing processes act on the moon? Can impacts resurface a landscape?
Sd. The Sandbox ofMars. Fig. 2 shows an area in Mars' southern hemisphere. On the flgnre or a photocopy, sketch or trace out all the circular rim craters you find (also oufline incom plete circles). Then, draw a boundary line that separates areas with many craters from areas with few or no craters. WItich of the two areas is younger? Remember that liquid water cannot exist on Mars' surface now-what processes that don't require water could have resurfaced Mars? Look at the long, twisting feature that goes from the upper right comer to the middle of the left side of Fig. 2. Does anything on your state map have the same Itind of swerving path? The feature might be a river bed, now bone dry (of course). What was Mars' climate like when water flowed in that river? What happened to the water that once flowed in the river bed? Where is it now?
7
Fig. 2. Ancient cratered highlands ofMars, east of the Hellas Basin. Scene is about 300 kilometers across.
Activity 4: Canyons and Valles Marineris



The great canyon system of Valles Marineris stretches
4&}() kilometers across Mars. Figure 3 shows part of lus
Chasma, the southwestern part of the Valles Marineris.
4a. Working for Scale (Geography and Math). The scene of Fig. 3 is 600 kilometem east-to-west (left to right). At this scale, how many cenfimeters (or inches) on the figure represent 100 kilometers on Mars? How many kilometers from the top of the scene to the bottom? How big is the largest impact crater in the scene? How far is it across your home town?
Sketch the outline of your home state at this same scale - would it fit inside Ins Chasma? Which states would fit inside? Ins Chasma is about 5 kilometers deep. For comparison, how tall (in kilometers) is Mt. Everest, the tallest mountain on Earth? How tall is Mt. McKinley (Denali), the tallest in North America?
Find a map of Arizona or the western U.S. that shows the Grand Canyon. Trace the path of the Colorado River as it flows through the Grand Canyon. Now redraw your sketch at the same scale as Fig. 3. Which canyons in Fig. 3 are comparable to the
For More Inforr~ation
Grand Canyon? How wide is the Grand Canyon, and how wide are the canyons on the south side of Jus Chasma?
Advanced: Imagine you are standing on the floor of lus Chasma at its south wall, at the very eastern edge of Fig. 3. How tall does the north wall of the Chasma appear to be? As tall as a telephone pole seen from a block away? Did you consider that Mars is a spherical planet (more or less) and that its surface is curved?
4b. Straight and Crooked Paths. Ins Chasma is basically straight because its edges follow huge geologic faults. On a map of your home state, trace out the channels of rivers and streams; are any of them straight like lus Chasma? From a map of Arizona, trace the main channels and canyons in the Grand Canyon. Is the Grand Canyon as crooked as the canyons on the south wall of the Chasm? Find the East African Rift on a topographic map of Africa. The Rift's walls are huge geologic faults-are any parts of the Rift as long and straight as lus Chasma?

Carr M. (1981) The Surface of Mars (book) Yale.
Wilford J. N. (1990) Mar~ Beckons cbook) Knopf.
LPI Home Page - http://cass.jsc.nasa.govlpi.html
LPI Image Collection- http://cass.jsc.nasa.gov/publicantions/slidesets/lpislides.htm
The Solar System - http://bang.lanl.gov/solarsys/

Mars Patnflnder - http://mpfwww.jpl.nasa.gov/

Mars Global Surveyor - http://mgs-www.jpl.nasa.gov/

Mars Surveyor Orbiter - http://nssdc.gsfc.nasa.gov/cgi-bin/database/www-nmc?MARS98S
Mars Surveyor Lander - http://nssdc.gsfc.nasa.gov/cgi-bin/database/www-nmc?MARS98L
NASA On-line Resources for Educators - http://www.hq.nasa.gov/office/codef/education
http://cass.jsc.nasa.gov/expmars/edbrief/ledbrief.html

Mars Pathfinder Fact Sheet

Mission Summary
The Project began the Assembly, Test Launch, and Op erafions (AThO) phase as scheduled on June 1, 1995. The activifies include the assembly of the spacecraft, and system test and verification that includes both hardware and software. The tests are a rehearsal of the launch, cruise, TCM, and sol 1 and sol 2 phases of the mission.

The Mars Pathfinder mission is the second launch in the Discovery Program, a NASA initiative for small planetary nussions with a maximum tleree-year development cycle and a cost cap of $150 million (FY92 equivalentS) for development. The Mars Pathfinder project is managed for NASA by the Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California.The mission is prftnarily an engineering demonstration of key technologies and concepts for eventual use in future missions to Mars employing scientific landers. Pathfinder also delivers science instruments to the sur face of Mars to investigate the structure of the Martian atrnosphere, surface meteorology; surface geology; form, and structure, and the elemental composition of Mar tian rckks and soil. In addition, a free-ranging surface rover is deployed to conduct technology experiments and to serve as an instiurnent deployment mechanism.

Mission Description

The flight system is launched on a Delta Ir-7925 I launch vehicle which includes a Payload Assist Module (PAM)-D upper stage, from the Cape Canaveral Air Force Station. The mission launch wm dow is a 24-day period beginning on Lecember 2, 1996.

After launch, the spacecraft requires 6 to 7 months to reach Mars, depending upon the exact launch date. During this phase, a series of four Trajectory Correc tion Maneuvers (TCM) is planned to fine-tune the flight path. Tracking, telemetry, and command opera- dons with the spacecraft are conducted using the gi ant dish antennas of the NASA/JEL Deep Space Net work (DSN). Upon arrival at Mars on July 4, 1997, the spacecraft will enter the Martian atmosphere, and then deploy the parachute, rocket braking system, and aft bag system for landing. After landing, the airbags are retracted and the lander uprighted in preparation for the surface operations. At this point, the primary data- taking phase begins, and continues for 30 Martian days or sols (1 sol = 24.6 hours).During this time, the mkrorover is deployed and op erated for at least 7 sols. If the lander and rover con tinue to perform well at the end of this period, the lander may continue to operate for up to one Martian year, and the microrover for up to 30 sols.

Major Mission Characteristics

Launch Period: December 2-25, 1996

Launch Vehicle: Delta II - 7925

Trajectory: 6-7 months

Primary Mission: Land on Mars - July 4, 1997

Complete Surface Mission: August 1997

End of Project: September 1998

Flight System Characteristics

Launch Mass:870 kg (includespropellant)
Entry Mass: 566 kg

Lander Mass:325kg
Basic Design:

· Aeroshell, parachute, solid rocket and air bag entry; descent, and landing (EDL) system

· Self righting, tetrahedral lander

· Active thermal design for lander

· Free-ranging rover

Command and Data Handling: Integrated Attitude and Information Management System (AIM)
Computation: R60OO computer with VME bus, a range of 2.5 to 20 millions of instructions per second (mips), 128 Mbyte mass memory
Power: Gallium Arsenide/Germanium solar-powered cruise stage and lander
· Cruise power - 250 to 460 watts
· Surface daily energy available -1080 W-hours Telemetry and Command:
Surface Operations Telemetry Rate via High
Gain Antenna (HGA), X-band: 1.2 to 12 kb/s to
70-rn Deep Space Network antenna
Surface Operations Command Rate via HGA,
X -band: 250 b/s
Propulsion:
· Monopropellant hydrazine used for cruise
· Eight 4.4-N thrusters
· TotalAVofl3Om/s


Total mass: 16 kg
Mobile mass: 11.5kg including APXS deployment mechanism and APXS instrument Lander-Mounted Rover Equipment Mass: 4.5 kg including ultra-high frequency (UHF) modem and support structure
Autonomous Navigation: Onboard, using laser striping for obstacle detection
Mobility System: Six-wheel, rocker-bogie suspension
Command and Telemetry: UHF link with lander
Payload: Aft and fore cameras, APXS, APXS deploy ment mechanism
Power: 0.25-m² solar panels - peak power 16W-hours; primary battery - 150 W-hours
Thermal Control: Three radioisotope heater units
(IIIIU)
Computer Characteristics: 80C85, 0.1 mips, 0.5 Mbyte RAM mass storage, 0.5 kg, 1.5 W
Surface Operations Time: 10 a.m. to 2 p.m. each Martian day (sot)

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