SCIENCE IN SPACE

something ln2 starting by pressurization how the thanks what text in the middle of the 20th century or the first time in history man reached beyond his planet and began to probe the mysteries of space [Music] this is one of the tools with which man is creating a new age but the age of space is also the latest chapter in a story as old as man himself according to myth Alexander the Great tried for the moon he used Griffin's which flew upward to catch a sheep's carcass kept always out of reach an 18th century adventurer thought he could use willpower to get to outer space a French balloon designer provided everything the space traveler could desire Jules Verne more mindful of the laws of nature conceived of a monstrous cannon and a moon ship carrying three men and two dogs according to his story one of the dogs died and was cast into space where he went into orbit less than a hundred years later the dog Laika was carried into orbit by a Soviet satellite [Music] - monkeys able and Baker traveled 300 miles out into space and back in the nosecone of an American rocket and man himself got ready to follow [Music] man first developed sounding rockets that gave him new insights into the upper atmosphere these tools opened a window and the masking layers of the lower atmosphere and through this window man caught glimpses of the true nature of the particles radiations and forces in near space although a sounding rocket radios back a profile of the atmosphere its flight is over in ten minutes or less man needs more than this he needs first-hand data from near space and beyond reporting events and changes over long periods of time and wide stretches of space today satellites can stay in outer space and report continuously on a wide variety of phenomena from cloud cover and the Earth's magnetic field to radiations and particles from the Sun and beyond according to their objectives satellites come in many sizes and shapes how do they function first of all to reach space a satellite depends on a rocket system more powerful than ordinary sounding rockets this system must include guidance or navigation equipment to direct it on a predetermined course the vehicle usually consists of more than one rocket or stage most of its weight is taken up by propellants both fuel and oxidizer launching is not an easy task in the countdown each step must be scheduled exactly checked and rechecked still there are no guarantees [Applause] in man's greatest pioneering effort his advance into space there are inevitable problems and agonizing trials but one by one problems give way to solutions in the first two years of the Space Age 20 scientific satellites and space probes were launched successfully six russian and fourteen american [Music] the most precious component of a space vehicle is its payload the satellite itself here are the electronic eyes and ears the brains and voice that measure and report temperature composition and structure of space these instruments skillfully miniaturized provide scientists with observations hundreds and thousands of miles beyond our planet [Music] one of the important elements of this instrument package is an 8-ounce tape recorder it stores the data collected by the satellites measuring devices and plays it back quickly on command from a ground station either on command or continuously the collected information is broadcast back to earth by tiny transmitters various combinations of instruments are assembled depending on the scientific objectives components are installed as compactly as possible space like weight is a critical factor to place each pound of satellite into orbit hundreds of pounds of rocket may be needed [Music] this satellites magnesium shell provides maximum strength with minimum weight several thin metallic coatings including pure gold help maintain the proper internal temperature range while the satellite is in orbit each satellite has its own special features on Sputnik three for example metal flaps open and close to control temperature on other satellites such as Explorer 3 reflecting oxide stripes maintain the average inside temperature between reasonable limits 30 and 100 degrees Fahrenheit [Music] although the Sun creates a heat problem it also acts as a source of power solar cells is on the paddles of Explorer six convert sunlight into electricity recharging the satellites batteries [Music] laboratory tests help to ensure that the payload will withstand not only the intense vibration of launching and flight but also in some cases the strain caused by spending hundreds of revolutions a minute other tests ensure that the rockets nose will open up and fall away so that the satellite can be separated from the rocket system finally all is ready how is the satellite placed in orbit why does it stay there although there are many vehicles satellite combinations the Vanguard offers a good example of basic technique 72 feet long as tall as a seven story building the three-stage rocket takes off bearing the satellite its path has been set before launching guidance equipment in the second stage keeps it on course about two minutes after launching nearly forty miles above the earth the first stage burns out falling into the sea as the second stage fires the rocket continues along a curved path it is now climbing through such thin air that shielding from air friction is unnecessary the nose cone is jettisoned nearly five minutes after launch 140 miles out the second stage burns out the rocket coasts on to a height of about 300 miles at this point it is traveling parallel to the Earth's surface however the vehicle is traveling only 9,000 miles an hour not yet fast enough to overcome the pull of gravity and stay in orbit inside the second stage the third stage containing the satellite now begins to play its part small rockets started spinning on a turntable when the spinning reaches a hundred and fifty revolutions per minute the second stage is separated its job completed stabilized by its spin the third stage fires and gathers speed then it too burns out and ejects the satellite into orbit at 18,000 miles per hour the speed at which the satellites movement forward matches its fall toward Earth and thus keeps it in orbit 300 miles out beyond the dragging effect to the lower atmosphere it continues to move at its original orbital velocity depending on their orbits some satellites circle the earth about once every 90 minutes others may take hours more satellite orbits like those of the planets are elliptical with a far point the apogee and a near point the perigee after many such orbits most satellites encounter enough atmospheric drag at perigee to slow them up a little this drag eventually causes them to plunge into denser atmosphere and be burned up by friction with a high enough perigee some satellites will remain in space virtually forever Vanguard 1 launched in 1958 achieved an initial perigee of 409 miles and an apogee of 2465 miles it may stay up for hundreds of years looking for a satellite is almost like dragging the Pacific for a golf ball some of them can be seen by the naked eye or with binoculars but only around Twilight however scientists have developed systems far more powerful and precise than the eye to follow space laboratories and to communicate with them special radio devices track a satellite by measuring the direction from which its radio signals come from successive angles of direction the satellites orbit can be computed amateur radio operators also pick up and report the satellite signals radio tracking networks stretch around the world another international network consists of optical observation stations man by volunteer teams engaged in operation moon watch using telescopes these observers are especially helpful in finding a newly launched satellite and in following a dying satellite in its final variable course each observer is assigned his own sector of sky upon sighting the satellite the observer such as this member of a Philippine team calls out in time out a series of moon watch reports coordinated with a recorded time signal helps implying the path of the satellite photographed by a moon watch observer in Schenectady New York this actual fast motion shot shows the tumbling third stage rocket of Sputnik one crossing the sky in front of the moon the most precise tracking system is the International chain of optical observation stations equipped with specially designed cameras a dozen of these were stationed around the world during the International Geophysical Year taken by one of these cameras this photograph with its dark and light elements reversed for clarity shows the track of Sputnik 3 against a background of stars here the aim of the camera was fixed and the satellite track registered as an intermittent line showing camera time marks the camera can also follow a satellite the resulting photograph shows it as a point in this example Vanguard 2 with the various planets and stars appearing as lines a series of these photographic records provides an accuracy of satellite position within one 18 hundredths of a degree in space and one thousandth of a second in time orbital data are sent to computing centers which process the observations and reduce them to a mathematical description of the satellites past history and present orbit here two predictions are made as to the satellites future course what about the information obtained through satellites in the first few years after the earliest successful launching a number of unexpected but very significant findings were made two of these were made possible by precision tracking the first finding interpreted from tracking data of Vanguard one provided new facts about the shape of the earth facts that could be obtained only from a satellite my new differences in the repeated measurements of Vanguard ones orbit led scientists to believe that the Earth's gravitational effect on the satellite varied in certain areas and thus the distribution of the Earth's mass must vary these variations caused scientists to change their concept of the Earth's shape greatly exaggerated here the differences between the old outline and the new slightly pear-shaped one are actually no more than about 50 feet places but this refinement however small is of great importance to a better understanding of the nature of the Earth's crust and interior a second major finding was obtained from studying the slowing down of Vanguard one caused by atmospheric drag this graph indicates how the drag on the satellite increased substantially following flares on the Sun this finding led to a new theory charged particles streaming toward Earth after solar flares increase atmospheric density enough to affect two satellites orbit satellite tracking data provide information about another factor nearer earth the atmospheric density which ultimately destroys them by studying the decline of a satellites orbit as air drag slows it up scientists compute atmospheric density at many levels analysis of such data has established that at heights of 200 to 400 miles air density is at least 10 times greater than was estimated in the days before satellites in addition to the information that they can deduce from observing satellite orbits scientists obtain much direct data by listening to the instruments carried aboard the satellite itself signals from satellite instruments are received as a kind of electronic shorthand or code the various signals are identified by changes in their length in the time intervals between them and in their frequency these messages are recorded on the ground in permanent form for later analysis this technique is known as telemetry for instance a special metal strip on the satellite surface and a microphone inside record out in space the erosion and the impact caused by tiny particles of dust known as micro meteorites from telemetered reports of this bombardment it has been estimated that as much as 10,000 tons of these particles enter the Earth's atmosphere every day micro meteorites are so minut they are no appreciable hazard for space vehicles satellites not only look out into space they also look down on the earth and can provide meteorologists with worldwide coverage of cloud formations this is the first weather image ever transmitted from a satellite recorded by a scanning device in Explorer 6 orbiting 17,000 miles above Earth it indicated cloud cover over a broad area in the Central Pacific this technique will permit man to track and predict the movement of great destructive storms satellites also tell man about strange forces and events in space they measure the Earth's invisible magnetic field whose lines of force reach out tens of thousands of miles in giant arcs they detect ultraviolet light and x-rays which are almost completely absorbed in the middle layers of the atmosphere they record primary cosmic rays streaming from space and occasionally from the Sun these so-called rays are actually atomic particles which travel at very great speeds high in the atmosphere they collide with atoms and molecules of gas thereby creating secondary cosmic rays which penetrate the atmosphere and can be recorded on or near the Earth's surface but to investigate the primary rays directly scientists must send their instruments high above the atmosphere satellites provide an especially good means of keeping the instruments up there for long periods in the course of probing cosmic rays American satellites made possible the most significant finding of the Space Age the discovery of the vast and complex regions called the Van Allen radiation belts below about 400 miles the 1st and 3rd American satellites found the amount of cosmic radiation that scientists expected but farther out the satellites found radiation so intense that their Geiger counters were temporarily saturated measurements by a later satellite showed no tapering off as far out as 1400 miles instead the radiation seemed to double in intensity every 60 miles of altitude late in 1958 space probe pioneer free reached out 66,000 miles and recorded two peaks in radiation intensity one at 2000 and another at 10,000 miles pioneer 3 also traced out the outer region of the radiation these findings led scientists to believe that two great zones of radiation encircled the earth under the influence of the Earth's magnetic field space probe pioneer 4 confirmed these findings and recorded fluctuations in the farthest regions of the outer zone scientists believed that the outer radiation zone consists of electrically charged particles ejected by the Sun streaming through space these particles are trapped in the Earth's magnetic field the inner zone is generally believed to be created by cosmic rays bombarding the Earth's atmosphere in this bombardment high-energy neutrons are created low in the atmosphere some of them travel rapidly to high altitudes where they change spontaneously into charged particles these particles are then trapped in the Earth's magnetic field new details are being added to the picture of this highly complex region that surrounds our planet its discovery is a most important step in sounding the endless sea of space space probes are reaching out beyond the Van Allen belts they have reached the moon and encircled it the third Soviet space probe produced this photograph of the hidden far side of the moon in placing a satellite in orbit around the moon three major motions going on simultaneously must be taken into account the Earth's spin on its axis the orbit of the moon around the earth and the orbit of Earth and Moon together around the Sun variations in the angle between the moon's orbital plane and the Earth's axis must also be considered all these factors complicate the task of traversing 250,000 miles from Earth to moon a lunar rocket needs enough velocity to carry the vehicle beyond the pull of Earth's gravity in the direction of the moon even after the probe escapes from the earth the moon is still two days away the last stage slows up by retro rocket bursts the moon's gravitational field sweeps it up the satellite acts as a watchful reporter sending back new data about the moon's composition its size and its mass and the radiations and particles near it [Music] this is Earth in the mid 20th century most of us remember when the moon was its only companion but since october 4th 1957 when Sputnik one went into orbit the Earth's community has been growing now there are several companions watching listening recording increasing man's knowledge day by day tomorrow's satellite will be an even greater tool for science satellites will give meteorologists round-the-clock reports on worldwide cloud patterns and trends thus allowing more accurate and complete weather forecasts satellites will relay man's radio signals greatly improving his worldwide communication networks satellites and probes will help astronomers find answers to questions about our neighbors in the solar system deep probes near the Sun will give earthbound solar physicists more information about the incredibly hot electrically charged atmosphere of our nearest star as for the day after tomorrow satellites and probes may bring man closer to stars far beyond our Sun within our framework of time and space journeys by man himself beyond our solar system are still inconceivable but through his scientific instruments carried by deep space probes far beyond his own limits man can reap new knowledge of distant stars and galaxies science in space helps men understand more and more that planet Earth and the solar system are only specks in a vast cosmos there may be other forms of matter and energy other kinds of worlds even other forms of living things [Applause] man's spirit is his most powerful drive in the words of the Norwegian scientist frig off Nansen the history of the human race is a continual struggle from darkness toward light it is therefore to no purpose to discuss the use of knowledge man wants to know and when he ceases to do so he is no longer man [Music] [Applause] [Music]