MAN INTO SPACE PART III

here is man in an unearthly environment weightless 100 miles out in space in speed of five miles a second is pulling him out words gravity is pulling him in so he's held in a curving path around the earth here is man and a new role for these few minutes is himself a satellite [Music] man's achievement in orbiting a spacecraft is only a few years old but the laws that govern how a body moves in space or as old as the universe itself and we've understood them for quite a long time back in 1687 Newton worked it out in theory now he reasoned that if you could somehow hurl an object at just the right speed and what was very important hurl it above the resistance of the Earth's atmosphere then it would stay in that circular orbit going around the earth forever he also understood that when it was launched it had to be moving horizontally to the Earth's surface if it were going straight up then the force of gravity would just slow it down and it would fall back down to the earth under the mathematics gave him the precise be needed for a circular orbit but it's just about impossible for a real rocket to get that precise speed for a circular orbit so most real orbits end up in what's called an elliptical shape that is there further away from the earth on one side and they are on the other the planets move around the Sun and elliptical orbits and the moon moves around the earth in an elliptical orbit to here is the launch vehicle rising slowly at first through the densest part of our atmosphere half its fuel has gone now it's lighter it's going through thinner air meeting less air resistance it tilts flies parallel to the earth a final boost speeds it up to more than 17,500 miles per hour into orbit around the earth as the satellite moves out gravity steadily slows it down so that finally is moving so slowly but it can no longer resist the force of gravity it has gone as far from the earth as it can at this point on the orbit is called apogee or the far point of the orbit then it begins moving back down toward the earth in a long looping downward curve it X up speed as it goes until finally it quits around this portion of the orbit moving so fast that it can go back out again on the same elliptical path this point is called parity or the near point of the orbit if the satellite meets no air resistance to slow it down it will stay in orbit indefinitely if it does go down to a little bit of the Earth's atmosphere here at perigee then it will be slowed down just a little bit it won't be able to get out quite so far on the next orbit it won't be able to get out to the same apogee each time it goes around it will be slowed down a little more and each orbit will be a little smaller scientists call this process orbital decay finally the whole orbit is inside the atmosphere what happens then well the satellite can't keep going fast enough to stay in orbit but it's still going several thousand miles an hour as it rushes through the atmosphere it compresses the air in front of it and the compressed air gets hotter and hotter this great heat is transferred to the satellite that's pushing against the air it begins to get hot too it gets red hot and white Hawk and unless it has some special heat protection it will burn up to get a satellite into an orbit that will stay above the atmosphere we needed powerful rockets and we needed to perfect a new idea called staging placing one rocket on top of another [Music] in the 1950s we were testing the redstone rocket a compared to our modern moon rockets but in those days it was one of our largest dr. Verner von Braun was one of a group of scientists who wanted to modify the Redstone add other rocket stages on top and use it to launch a satellite their tests seemed to show that it could be done however a decision was made to build a new rocket the most advanced rocket up its time the Vanguard built the launch an artificial satellite in 1957 1957 was the year of the first Earth satellite a Russian satellite a 184-pound metal sphere called Sputnik 1 it radio back towards the first signals from space one month later came Sputnik to 1,000 pounds this time it even carried a dog the first space traveler and the new vanguard didn't look as if it would ever get off the ground the Russian accomplishment amazed the world many people said that we should be working together not as separate nations but as mankind against the unknown other people spoke of the space race and Russian satellites were up there so the question was why and the answer went back to the time when the Russians were building rockets to launch their first nuclear bombs these early bombs were big and heavy so the rocket to launch them had to be very powerful this meant that the Russians had large powerful rockets with which they could launch very big spacecraft our rockets were comparatively small because we had chosen big airplanes for national defense when the space program began and rockets were to be used for peaceful purposes the Russians had big boosters ready to go American engineers had some hard work ahead of them the first job was to launch a satellite 80 days after Sputnik 1 America launched its first satellite explorer 1 a modified redstone put it into orbit just as von Braun had suggested vanguard 1 and Explorer 3 followed making 5 earth satellites in just 6 months now we could send up satellites to get information we could never get before the satellite radio the information back by telemetry the limit rate changes the small movements and signals from measuring instruments into an electronic code the instruments might be measuring temperature or counting meteorite hits or taking photographs even photographs can be changed into a code on relayed it looks like a series of numbers Computers change the code back into photographs telemetry reports from early satellite told us the earth was surrounded by huge donut the solar radiation the Van Allen belts chemical batteries run down too quickly in space so we developed solar batteries these are the shiny silicon cells you see on the outside of many satellites they convert sunlight into electricity to power the instruments and the transmitters on board now we use satellites every day big storms caused fantastic damage each year when we know ahead of time that big storms are coming we can prevent some of the damage if we could learn why they happen we might even be able to stop them weather satellites send us pictures of the earth and its clouds from 500 miles in space from this we can learn more about the changing weather patterns satellites also report on the activity of the Sun knowing how the atmosphere absorbs solar radiation is vital to understanding how our weather is formed we use satellite to send radio and television around the curve of the earth the first communication satellite was echo 1 a huge plastic balloon you're watching it being inflated in space radio signals were bounced off its surface today's communication satellites carry their own receivers and transmitters in 10 years more than 600 satellites were sending us messages from the space around us getting our first satellite into orbit was hard enough but getting our first man up there was an enormous undertaking there were many things we didn't know what would happen to an astronaut the acceleration after liftoff we knew he would be subject to very powerful forces how would he react there are many people who L he would be helpless unable to do any work then there was the problem of weightlessness we could do tests and airplanes for a minute or two but no one really knew what would happen to a man in space our astronauts went through extensive training and medical testing to see if they could withstand the rigors of space most important what about the feeling of being alone up there what would that do to a man's mind we said about finding the answers with the Mercury program our first astronaut was Han a chimpanzee he tried out the castle taking acceleration and reentry pressures successfully in 1961 a man orbited the earth for the first time a Russian cosmonaut Yuri Gagarin yeah yeah I Guardian done yet [Music] [Music] now we all knew man could travel in space he can survive the strain of getting up and getting back to American test flights launched astronauts in the new Mercury capsule from Florida eastward to the Atlantic Ocean the first American went into orbit the following year the athletes was the booster vehicle the little mercury capsule perched on top John Glenn squeezed into the castle and the final countdown began mandatory they just check pressurization rocks tanking power blinking high level like you are gold ola call retract now range operations ok Mercury capsule no I'll pre-start now I took correct the ready light is on eject Murphy umbilical oil evacuate for Korea Pulickel clear margarito it lights on our recorders too fast t-minus 18 seconds and counting engine start you have firing signal good lord ride all the ways you godspeed john glenn t-minus 10 9 8 7 6 5 4 3 2 1 0 [Music] we all shared the tension of that flight just before reentry we thought the heat shield might have slipped we were afraid there was something wrong with the retrorockets but everything worked the machines and the people did just about everything they were expected to do and we honored a new hero John Glenn [Applause] the following mercury flights were longer and they confirm that man could live and work in space the Russian and American manned space programs had very similar goals they duplicated each other but the Russians did many things first orbiting the Earth to man spacecraft valentina tereshkova a woman in space space walks [Applause] back in 1961 president john f kennedy had promised that we would land a man on the moon by 1970 and to do this we had to take several steps we had to build a very powerful rocket we had to build a bigger spacecraft we had to learn how to adjust the orbit of a spacecraft and how to join up one orbiting vehicle with another the mercury flights at Jonah's man could be a space passenger the Gemini program would tell us if he could be a space pilot as well orbitz changes rendezvous docking or joining two spacecraft together these were the important elements of the gemenese story there is edward white walking in from space top it off rates are up a bottle up the gray / soccer betting on about half to be protected and roll here are germany and discuss to continue at the description of one being autograph from the other they're moving at 17,500 miles an hour the pilots are flying them to within 18 inches of each other in the windows of six very easily and vice versa this was the mission that many people think was the turning point in America's space effort in the Gemini 9 mission the astronauts rendezvous with the target vehicle they nicknamed the angry alligator but no docking could take place Germany 10 successfully docked with the Agena target vehicle and fired the Agena zengin to propel it into a higher orbit an important maneuver in a mood mission less than 10 years had gone by since we put up our first little earth satellite and now we could put men in orbit we were ready for the next great adventure the Apollo missions and the moon and that's the next part of our story [Music] [Music] [Music]