>> the smithsonian air and space museum opened 40 years ago. leading up the anniversary, real america is showing a series of massive films. marsxt, from 1979, "planet ." this film documents the search to understand our solar system positive most earthlike planet. it includes an overview of the mariner flyby of the red planet from 19 six four and 1971 and the viking mission that crashed on the surface in 1970 x.

-- 1976. ♪ >> of all the planets in solar system, earth and mars are the most similar. despite the similarities, mars is like no other planet. it is a unique world. it was elusive for hundreds of years. human telescopes show it was a red sphere. it was estimated to be half the size of earth.

one of the earliest known representations of the planet was drawn in 1559 indicating markings on the surface. it was shown that mars rotated on its access. about 24 and one half hours. it was observed to that the tilt of its access exposed to the polar regions ultimately to the sunlight. each hemisphere has a summer and winter. since mars rotates the sun. it is almost twice as long as earth. later mappings of the planet has made dark and light regions as continents and oceans.

the water, a greenish blue. in 1877, and italian astronomer discovered channels resembling the finest threads of a spider's web. in america, he founded an observatory to study these findings. he called the massive irrigation systems. science-fiction writers populated the city with terrible features. in the 1960's, a spacecraft flew by mars and photographed about 10% of the surface.

the photographs revealed the landscape much like the moon. in 1971, the spacecraft orbited mars. it and build a new and unexpected world. the southern hemisphere was couched by it many meteorites. the northern hemisphere was a vast plain with few craters. the plateau that joins this is cut by a vast and deep canyon. it possibly adapted to mars's

changing conditions. then in 1975, 2 viking spain -- spacecraft was launched. one of its principal objectives was the presence of learning organisms. the communication system in pasadena california. on june 19, 1976 the first viking arrived after a journey of 400 million miles.

once in orbit, its cameras were turned. imaging teams covered a territory the size of texas. one of lois regions. on july 20 flight controllers looked at the orbiter. the signal traveling at the speed of light took 19 minutes to reach the spacecraft. the instrument analyzed the properties of the thin martian atmosphere. >> 200 feet per second. acs is close to vertical.

this necessitated an automated system on board. descent, it is a look at the thin martian atmosphere. >> -105. >> four by three sing. >> 177 feet per second. >> 105.3 geez.

>> slowdown. >> 60 feet? >> acs is close to vertical. >> go for touchdown. >> matchpoint to jews. [cheering] >> fantastic. we have a touchdown time of 12 hours, 12 minutes and decibel one seconds. >> job well done. perfect. i'm assuming we must be sitting right on the x. 25 seconds after landing, they scanned pictures of the service.

>> about half an hour later, and we got the first seven lines you can see gray and white levels. we were looking at the surface of mars and it was clear and not dusty. it was a miracle. >> in an instant, it was wiped off tv monitors. it extends from the lander.

it was littered with rocks. the following day viking sent back the first color picture. 45 days after these historic events, biking to landed in an area. it was produced by volcanic processes or meteor impact. the lander conducted experiments on the surface. the orbiter swung around.

it took high resolution photographs. it was formed from the garrison dust. in the formation of the planet, heat is relieved. because the heat can't escape as rapidly, it is reached eventually where the interior meds. a later stage may have occurred caused then rock

slurry of water, rock, and dust. some observers believe that the process may have been the cause of the major channels that we see on the surface of mars today. others leave that in its first billion years, the atmosphere may have been warm enough for rain to fall in four rivers to flow. gradually, the original thick, wet, warm blanket of the atmosphere evolved into the thin it and dry cartman dayan site atmosphere that we find there today. because of the low atmosphere pressure at low temperatures, water cannot exist in liquid form. it must either freeze or evaporate.

the residual polar cap in the is water and ice mixed with dust. the measurements of the seasonal behavior over the planet suggests that there is a vast reservoir of ice beneath the surface. so that one can think of the residual cap as the tip of an iceberg protruding from the sea. at lower latitudes it condenses to form clouds arrive at -- that ride high in the atmosphere. to the south, and the canyons and valleys, there is a haziness of forms and evaporates in the early hours of the morning. on earth, the heat and moisture of the ocean, heat and air currents of the landmasses

interact to produce intense weather patterns. on mars, because of the absence of large bodies of water's and massive cloud cover, the weather isn't -- doesn't very much from day-to-day. like a remote weather station on earth, the meteorology atmosphericeasures pressure, temperature, wind speed and wind direction. temperatures range from -122 degrees fahrenheit just after dawn to minus 22 degrees the afternoon. light wind from the east changing to light wind from the southwest after midnight. maximum wind speed is 15 miles per hour.

in yearly summer, the heating dust particles of the air generate violent dust storms and other regions of the planet. driven by wind that reaches 150 miles per hour, they may blanket the entire planet in a few days. >> in order to understand the geology and physics of windblown articles on mars, we are conducting a series of experiments using this at norma's chamber here at the research center. we placed an open circuit wind tunnel in the chamber and were able to operate at atmospheric surface pressures comparable to those on mars. in this particular series of experiments we have placed on the model on the floor and want to determine the zones of erosion and deposition around the crater. in this particular case we are going to let the wind blow

across the crater and see what those levels of erosion and deposition unlike. >> the light and dark streaks are the most common features related to the wind. the light streaks are deposits of fallout left over from dust storms. the dark streaks are the regions in which a thin layer of light material has been removed, revealing the darker underlying surface. these serve as wind markers, patterns defining the wind flow. to the geologist, the features seen in the tens of thousands of visible signs of the enormous processes that have shaped the surface of mars.

has impactedn meteorites and asteroids. theraising of mountains by action of volcanoes. the vaulting and subsiding of the crust. the cutting of channels by water . all abrasive articles driven by wins over tens of millions of years. the key to the sequence of these features is found in the number and an edition of the craters. those areas with the fewest craters are assumed to be the angus. lines.fresh crater over here it is eroded by water or wind. here, adjacent to a french

crater is one of a cluster of rings. craters buried to various death. over millions of years the repeated flows of lomba bill paul canada mountains. 12 are larger than any on earth. rises three times higher than mount everest and enough to cover the chain of volcanoes the cover the islands. the great cash coming to the equatorial zone as part of a mighty canyon system that extends over 3000 miles long and 4000 miles ride -- wide over the surface of the plateau. gulley,alls are dissected right should betray

kenyans and catastrophic landslide leaving deep rifts. extending for 30 miles on the canyon floor is a sand dune. removed by the wind. these ancient channels that resemble dry riverbed on earth could have been formed by primeval rainstorms. thatast channel system started in areas of terrain with broad lines extending hundreds of miles across the low lands, soaring toape thousands of feet above the bed. without -- without any parallel on earth. viking also photographed the moons of mars.

cobos, marked by striations on closer view that result into grooves several miles long. moon.en the smaller outer , passing only 30 miles away, could observe holders on the surface of the moon. some as large as 100 feet across. the geologic record of the planet suggests that mars, like the earth, has experienced periodic changes of climate. the best evidence of this is seen in the strange pattern of the polar region. clip the bare ground in the north polar ice cap. are numerous small terraces from layered rocks. layereda model of

terrain. an area about 40 miles ross. itis believed that represents two different cycles of changes that occur simultaneously. because of the oscillation in the orbit around the sun, the polar regions are alternately -- warm andd, with cold over tens of thousands to millions of years. mixtures of dust and ice are deposited in a series of horizontal layers. of securing the typography. then warmer climate followed with erosion setting in, cutting deep alleys and the icy mass of the polar cap. after the cycle, new layers were another episode of

erosion followed. this oblique truncating by one terrace over another indicate off.limate turns on and the first evidence for cyclical change on a planet other than the earth. the speculations about changes in the atmosphere, climate, were closely related to the notion that life in some form might exist on mars. earth, life developed several million years ago at a time when overall properties of mars and earth were very similar. >> over the ensuing billions of years, mars and the earth evolved separately. however, today at was chemicals on the surface, and atmosphere, pressures within which we believe life can exist. withiking lander was a bit

detection experiments designed to test for chemical changes caused by my processes familiar to us on earth. on earth, all living organisms interact with the environment. >> animals, for example, take oxygen from the environment and , thereby combust food obtaining energy. at the same time they release carbon but -- carbon dioxide and other waste buttocks into the environment. green plants and organisms do the reverse in a process of photosynthesis. they remove carbon dioxide from the environment and use sunlight as the energy source, converting it and releasing oxygen into the environment. >> if these experiments indicated that similar processes were occurring, then we would

resume the investment in organism on the planet. our results in some experiments give us data that seemed to mimic living organisms. however, careful analysis of the data indicates that it is probably the result of a chemical rather than a >> on earth,ocess all biological systems are based on organic chemistry and it was believed that life on mars would also be based on organic compounds. the notion was strengthened and experiments on earth demonstrated that are materials can be formed under similar conditions. >> we use finely powdered minerals, like those on the martian surface. then we added traces of water vapor and radioactive carbon

monoxide and low pressure. , weimulate martian sunlight irradiated the mixture with light. heeded the sample and capture the gases formed, the radiation counter showed the hadon locked side and water been converted io organic compounds. >> viking's instruments failed to detect organic compounds of any kind. that fact in the opinion of some increased the odds against living organisms on mars. >> if we were able to do 1000 different experiments on mars, to do these with a wide variety , in someents on mars deep areas of the surface, and

if all of these we got negative results, the answer to the question -- is there life on certainlyuld almost be no. but on the basis of just a few only twots done at sites, very bland sites on the planet, it would not be scientific for us to come to that conclusion. is that we can really say that we have run across some very interesting chemistry. the kind that we do not see an surface samples from the earth or from the moon. that's about where we are. today, in laboratories across the nation, scientists are trying to simulate the results we obtained on mars. some are concentrating on radiation experiments.

others are -- assuming that these experiments were there and are testing chemicals to see whether they can account for the results of gained. >> the question of life on mars is only one of the inexhaustible questions for which we continue to seek answers. questions about the evolution and origin of the solar system. about our own planet and when something -- and about our own species. answers is the goal of exploration. to journeys are beginning

provide some of the answers. ♪

>> july 1, 1976, the smithsonian national air and space lose him opened its doors to the public with gerald ford on hand for the dedication. american history tv's live coverage starts at 6 p.m. eastern. enter the museum, see one-of-a-kind artifacts. plus live artifacts at the front of the building. learn more as we talk with the , curator, and chair of the museum's history department. you can join the conversation. we will be taking your phone , e-mails, and tweets.

>> coming up next, stories about the current supreme court food traditions. including food preferences, topics of conversation shared meals. we also learn about customs dating to the 19th and 20th century from the supreme court curator. if this discussion place at the national museum of american history in washington and is over an hour. >> we are thrilled to see so many people here for this program. my name is john gray and i have the privilege of being the director of your museum of natural history. particularly on nights like tonight when we can look at american history in a unique way. we are honored to be joined by two nights panel. supreme court justice ruth bader ginsburg.