Referat The History of American Space Travel - Reasons for space exploration

The History of American Space Travel

"The earth is the cradle of mankind - one cannot remain in the cradle forever" - Konstantin Ziolkovsky

If you talk about space travelling you think about projects like Apollo 11, or futuristic films like Star Trek or something in this direction. You will think about the Mir or the Challenger. Every of those projects has to do with space travel and I will try to bring you the history of the American space travel near. I will write about the Mir too because it's very up to date at the moment. But first of all I'll write about the beginnings of space travelling and about the basic theories.

Working out the Theory:

To design and build a spacecraft, you need to be able to figure out how big to make it, how heavy it can be, how fast it will have to go, how much fuel it needs and so forth. For that, you need a theory of how objects move in space and how to make the calculations. Three brilliant men worked out almost all theory of space flight over a period of nearly three centuries - from 1600 to 1900

Johannes Kepler:

Was the German mathematician who, in 1609, figured out the equations for orbiting planets & satellites? In particular, he determined that the planets move in ellipses (flattened circles) rather than true circles.

Isaac Newton:

In 1687 he wrote what is probably the single greatest intellectual achievement of all time. In a single book he established the basic laws of force, motion, and gravitation and invented a new branch of mathematics in the process (calculus). He did all this to show how the force of gravity is the reason that planet's orbits follow Kepler's equations.

Konstantin Ziolkovsky:

A Russian school teacher who, without ever launching a single rocket himself, was the first to figure out all the basic equations for rocketry - in 1903. From his very broad and extensive reading including Jules Verne's "From the Moon" he concluded that space travel was a possibility, that it was in fact man's destiny, and that rockets would be the way to pull it off. He anticipated and solved many of the problems that were going to come up for rocket-powered flight and drew up several rocket designs. He determined that liquid fuel rockets would be needed to get to space, and that the rockets would need to be built in stages (he called them 'rocket trains'). He concluded that oxygen and hydrogen would be the most powerful fuels to use. He had predicted how, 65 years later, the Saturn V rocket would operate for the first landing of men on the moon

Building the first rockets:

Robert Goddard is the first man who built a rocket and is now called "the father of modern rocketry" By contrast to Ziolkovsky, Goddard was the man who designed, built, and flew the rockets. He was a university professor who also developed the theory of rocketry and although he didn't know about Ziolkovsky's work, reached the same conclusions as Ziolkovsky did. Goddard proved the theory was true. He was also heavily influenced by the science fiction of Jules Verne, and he worked hard to develop rockets because he wanted to see them take us into space. When he first published his superbly written study, proposing that rockets could possibly be used to travel to the moon, people thought he was a nut. In fact, the criticism was so harsh, Goddard maintained a low profile and said little about his work after that. In 1926 he launched the world's first liquid fuelled rocket. In the course of his experiments in Massachusetts and Roswell, New Mexico, he virtually developed the entirety of rocket technology. He invented everything required for modern rocketry and earned over 200 patents. By himself he developed the same components and designs that took the Germans hundreds of scientists and engineers and millions of dollars to develop independently at Peenemunde during World War II.

Convincing the world - Herman Oberth

Yet another one who, after reading Jules Verne's 'From Earth to the Moon' as a young boy (age 11 in this case), became determined to find a way to travel space. He independently determined the same rocketry principles as Ziolkovsky and Goddard. The difference with Oberth is that in 1929 he published 'The Rocket Into Interplanetary Space', a highly influential book that was internationally acclaimed and persuaded the world that the rocket was something to take seriously as a space vehicle. Oberth was also Wernher Von Braun's teacher, bringing him into the German rocket program. Of the three great rocketry pioneers, Oberth was the only one who lived to see men travel through space and land on the moon.

Taking Man Into Space - Wernher Von Braun:

Together with Oberth and an enormous team of scientists and engineers at Peenemünde, he developed and launched the German A4 rocket, the first rocket capable of reaching space. At the end of World War II, Von Braun led the top scientists and engineers out of Germany to the Americans (he didn't want to be captured by the Russians). Von Braun came to the top of the American space development caused by the " Sputnik-Shock" He led the US development of military and space exploration rockets. Von Braun was crucial in the effort to convince the US government to pursue a landing of men on the moon, and guided US efforts to success with the. He led the development of the Saturn rockets, the only series of rockets ever developed to have worked perfectly on every launch (that is, never blew up on the pad). If he hadn't been so successful, we may never have made it to the moon.

The principle of the rocket

Centre of Gravity:

Most people have at least an intuitive notion of the centre of gravity (CG) of an object: it is the point on which the object can be perfectly balanced. Grab a broom at one end and the other end tries to drop down; grab it at its centre of gravity, and it stays balanced, neither end tipping over. If you have learned to balance a chair or a broom on the palm of your hand, you know the trick is to place your hand right below the centre of gravity. Since your hand is not at the CG but below it, it must be constantly moved to keep that strategic position. There also exists a precise mathematical definition--it has nothing to do with gravity, which is why many scientists and engineers prefer the term centre of mass. However, it leads off the main subject and therefore we won't bother with it now. A lightweight stick with two balls of equal weight at its end obviously has its CG in the middle. When one ball is twice the weight of the other, the CG divides the distance between them by a ratio 1:2, in a way that makes it closer to the heavier mass (see figure). And similarly for other ratios

Balls that push each other

Now imagine that instead of a lightweight stick the above two heavy balls have a spring between them, held compressed by a string. Even though the balls are separate, one can speak of their common center of gravity, on the line connecting their centers, 1/3 of the distance from the center of the heavier ball. (The CG of the Earth-Moon system can be defined in the same manner. Since the ratio of masses of the two bodies is about 81:1, the CG is the point on the line between their centers dividing it by that ratio. It can be shown that--neglecting the pulls of the Sun and of other planets--the Moon does not orbit the center of Earth, but rather the common CG--and so does the Earth, reacting to the pull of the moon. Of course, since the Earth is much more massive, the CG is not very far from the center of the Earth--in fact, it is closer than the Earth's own surface.)Suppose next that a lit match is placed against the string, burning it through. As the spring expands, it pushes the balls apart; if it is sufficiently light, its own motion does not matter and we can assume that the balls push each other. By Mach's formulation of the equations of motion, if the heavy ball receives an acceleration a, then the light one gets 2a, twice as much. For each increment in the velocity of the heavy ball, the light one receives twice as much, and it follows that at any time, its total velocity, as well as the distance covered, are twice those of the heavy ball. If then the heavy ball is at a distance D from the initial position of the spring, the light one is at distance 2D--as in the earlier figure, reproduced here. No matter how much time passes, the center of gravity stays at the same spot.

Rockets

That turns out to be a very general principle: in any object or collection of objects, forces that only involve those objects and nothing else ('internal forces') cannot shift the centre of gravity. An astronaut floating in a space suit cannot shift his position without involving something else, e.g. pushing against his spacecraft. The centre of gravity--or 'centre of mass'--is a fixed point, which cannot be moved without outside help (turning around it, however, is possible). By throwing a heavy tool in one direction, the astronaut could get moving in the opposite direction, though the common centre of gravity of the two would always stay the same. Given a bottle of compressed oxygen, the same result follows from squirting out a blast of gas (a scene that appeared in an early science fiction film). A rocket does much the same, except that the cold gas is replaced by the much faster jet of glowing gas produced by the burning of suitable fuel The powerful rockets which lift hundreds or even thousands of tons off the launching pad depend on the same principle. If you ever watched a rocket lift off at Cape Canaveral, it is worth remembering that if you could somehow remove from the scene the launching pad, the atmosphere and the Earth, then the combined centre of gravity of the rocket and its exhaust gases would always remain where it started, at the launching point. It may seem like a roundabout way for producing motion. And yet, rockets are (at least for now) the only practical means of leaving Earth and flying into space.

Reasons for space exploration

Here are some reasons. One reason is colonization. In another 20 years it's estimated the population of the earth will reach over 8 billion. We need more places to live and we need the security that we, if the earth will be hit by an asteroid or if a nuclear war destroys our planet, can survive. That's only possible with colonies that are independent. What about industrial settlements on moon, if the industrial settlements are on moon the earth is free of toxic waste or stuff like that. Another one is international diplomacy: the Americans went to the moon to beat the Russians, now they are building the international space station as a way to work with the Russians. Go figure, in any event prestige and international relations are among the most powerful reasons we've had for going into space. Reason number three are natural resources, maybe we'll be able to mine the moon and asteroids for ores and minerals, the resources of the earth are limited and if we mine on asteroids or other planets the resources won´t end suddenly. The best example is oil. We don't have so much oil on earth but maybe on other planets is more oil or a completely different form of energy. Another one is researching the universe - orbiting observatories like Hubble Space Telescope, Advance X-Ray Astrophysics Facility (AXAF), and Cosmic Background Explorer (COBE) to study the stars, galaxies and the structure of the universe. Peter Kokh said the moon's surface is going to teach us a lot about the history of the universe. First of all, he said, the moon is 4.6 billion years old and remains untouched. It also has a two to five yard- (1.8- to 4.5-meter) thick layer of moon dust that bears a record of solar activity and weather going back billions of years. Kokh said, 'since the beginning, the surface of the moon has been buffeted by the solar wind of particles emanating from the sun.

Chronic of Space Exploration

The female apes Able and Baker were the first animals that survived a space flight. They survived a 15 minutes flight in a height of 500 kilometres.

MERCURY

The first Mercury rocket was shot in the December of 1960. It was a Redstone rocket and made a unmanned ballistic flight.

January

Shimpanse Ham in the same rocket as Mercury 1 on a ballistic flight on board of Mercury2.

April

Mercury3 with an Atlas rocket had an unmanned false start.

May

Alan Shepard was the first American in space; he made a 15-minute ballistic flight with the cap Freedom 7 on Mercury 3 but not with an Atlas rocket but with an Redstone rocket. In this mission Sheppard tried to steer the space ship manually with the board instruments.

July

Virgil Grissom flew on Mercury 4 (Redstone) 16minutes long, 190km high and 500km far. His cap Liberty Bell 7 sunk and Grissom was rescued dramatically.

September

Mercury4(Atlas) rocket had a splash down after 1 earth orbiting, it was unmanned.

November

The Test schimpanse Enos was born alive on board alive of Mercury 5

February

On the 20. February John Glenn had gone around the world for 3 times with "Friendship 7 and Mercury 6. He was the first American in earth orbit. His flight lasted 4 hours and 55 minutes.

May

Scott Carpenter landed 400 km far from his calculated landing point with Mercury 7.

October

Wally Schirra landed his 1374kg rocket Sigma7 only 8 km from the salvage vessel. On the first day after the landing he had problems to adept on earth conditions.

May:

Gordon cooper made a record flight on Faith7. He solved many board problems.

Virgil Grisshom and John Young were the first American team of astronauts. Their rocket was "Gemini 3" they orbited the earth for 5 hours on the 23. March.

Edward White, on board of "Gemini 4" with James McDivitt made the first American space walk. He was in space for 21 minutes and broke the record of the Soviets over 3 minutes.

James Lovell and Frank Borman spent 13 days on board of "Gemini 7" in the earth orbit and they came very near to "Gemini 6"

Neil Armstrong and David Scott made a dock on with "Gemini 8" on an Agena target body. It was the first dock on manoeuvre in space.

APOLLO

The US-space flight program was very young, as President Kennedy requested the NASA to bring a man to moon before the decade was over. 5 months an 11 days before the period was over, Neil Armstrong and Edwin Aldrin were the first men on the moon in 1969. 12 astronauts explored by foot or by vehicle the surface of the moon. They entered new land and got much important scientific information.

January

"Apollo 1". The Apollo-project started with an accident, it was the only fatal accident in the whole Apollo Project. The astronauts Virgil Grissom, Roger Chaffee and Edward White died one month before the start of the rocket because of a fire in the space cap. The fire broke out because the Americans used pure oxygen as atmosphere. That increased the fire risk. A short-circuit on an unfavourable place was enough to cause the catastrophe. The Astronauts suffocated.

October

Was much better than "Apollo 1" the numbering should show that too. Apollo 7 was a new start for the whole American space travel. They orbited the earth 168 times before they landed on the 22. October. After some Missions Walter Cunningham, Donn Eisele and Walter Schirra tested Apollo in the space

December

James Lovell, William Anders and Frank Borman flight with "Apollo 8" to the backside of the moon. They were in the orbit for 20 hours to explore a landing point because the lunar module called LEM wasn't ready at this moment. They orbited the moon 10 times and described it as an oasis in the space. This mission was very important because a further hurdle was taken.

March

The LEM was ready for a first test flight. Russel Schweickart, David Scott and James McDivitt on "Apollo 9" were the first who tried the off couple and dock on manoeuvres of the lunar module. The mission was completed without great disasters and the LEM had passed its first test.

Mai

The last test for the moon landing was "Apollo 10" Thomas Stafford, John Young and Eugene Cernan flew 15 kilometres near to the moon. They tested with the LEM Snoopy all manoeuvres in a moon orbit under the conditions that Apollo 11 will have. Apollo 10 was ready to land on the moon, but it was necessary to test it all under 1:1 Conditions. Because OF THAT Apollo 10 is very important too for moon landing.

July

Apollo 11

Neil Armstrong, commander

Michael Collins, commander module pilot

Edwin E. Aldrin Jr, lunar module pilot

"Apollo 11" made history with the first moon landing. The race for the moon found an end and the winner was America. It was one of the best missions in the history of space travelling. Neil Armstrong the first man on the moon became a national hero with the words: A small step for man, but a great step for mankind. But it was not sure if the whole crew would come back to earth. The Chances of the lunar module to start again were at 50:50. Collins was the one who stayed in the command unit while the others entered the lunar module walk on the moon. He should be the one who has to leave his friends if the lunar module wasn't able to start again. But everything worked perfect and the 2 astronauts landed on the moon without problems. On the 20.Juli 1969 at 20.18 MEZ the space ship eagle landed on the moon only a few kilometres from the calculated landing point. Armstrong landed the LEM perfectly on the moon. The return to earth and the splash down were nearly perfect. After their return the 3 astronauts had to stay in quarantine for 17 days because nobody had known if they brought lunar microbes to earth.

November

The mission target of "Apollo 12" was to find Surveyor 3 an unmanned space probe. Surveyor 3 was sent out in 1967 to check if there is dust layers on the moon which would make it impossible to drive a car on the moon or which would bring the moon landing ferry in addition too sink. Now it was Apollo 12´s turn to bring Surveyor 3 back to earth. Apollo 12 got problems seconds after the start because the rocket got hit 2 times by flash. The damages weren't very heavy and were repaired easily. Apollo 12 found the probe and brought it back to earth.

April

"Apollo 13" brought the space flight back into the middle of public interest. On the 13. April the astronauts James Lovell, Fred Haise and John Swigert heard a loud noise. 2 of 3 gas cells failed. But the gas cells were the smallest problem they had because one Oxygen tank was nearly empty and the second one was about to go empty. Without Oxygen the 3rd gas cell wasn't able to work too. What happened? The temperature in one tank was about 540 degrees because of that the cable isolation burned off and a short circuit was the follow. The tank exploded and damaged the second tank. The only thing that saved the astronauts was the lunar module. They orbited the moon and took curse on earth. They had to manoeuvre with the descent rocket of the lunar module.

January

Alan Shepard, Stuart Roosa and Edgar Mitchell were on Apollo 14 and explored new moon terrain. Shepard was the only one of the 7 Mercury astronauts, who was thereby during a moon landing. But this mission was not very spectacular; generally the first sub orbital flight of Shepard was more excitingly as this mission

July

Apollo 15 brought James Irwin, David Scott, Alfred Worden and the first moon vehicle to the moon. They described the car was like an intractable wild horse. With the car long distance trips were possible and things could be transported easier.

April

Charles Duke, John Young and Thomas Mattingly tested the moon cars down force. They drove circles and hard curves to see if the tires are good enough. They found out that none of the 94kg rocks that were collected from the moon, were from its time of origin.

December

At the last Apollo-mission Eugene Cernan, Ronald Evans and Harrison Schmitt broke all records. They were on the moon for the longest time, put back the longest way and got the most rock probes.

A few facts about the Russian space flight

Sputnik

Sputnik 1, launched on October 4, 1957, was the world's first artificial satellite. It had a mass of 83.6 kilograms. It was designed to determine the density of the upper atmosphere and return data about the Earth's ionosphere However, its two radio transmitters only returned signals to Earth for 21 days.

Sputnik 2 was launched on November 3, 1957, and carried aboard it a dog, Laika. This time the satellite weighed 508.3 kilograms. Biological data was returned for approximately a week (the first data of its kind). The data showed scientists how Laika was adapting to space -- information important to the manned missions already being planned. There was no safe re-entry possible at the time, so Laika was put to sleep. The satellite itself remained in orbit 162 days.

The third Sputnik satellite was launched on April 27, 1958, but it failed to reach orbit. It was destroyed 88 seconds after launch. It was not given a numeric designation.

Sputnik 3 was launched on May 15, 1958. It was designed to be a geophysical laboratory, performing experiments on the Earth's magnetic field, radiation belt, and ionosphere. It weighed 1,327 kilograms. The data was used as part of the International Geophysical Year efforts. The satellite orbited Earth and transmitted data until April 6, 1960. However, its tape recorder failed rendering it unable to map the Van Allen belts. All four Sputniks were launched using R-7, or SS-6 Sapwood, launch vehicles. Sputnik 1 and 2 used the R-7 8K71, and Sputnik 3 and the failed satellite used the Sputnik 8A91 launch vehicle. The Sputnik Missions caused a shock in the USA The launch of the Sputnik series and the Space Age that the Soviet Union brought in had a number of ramifications on the world around it. Since the Soviets were able to keep Sputnik relatively quiet, the Western countries were shocked when the satellite began its orbit. The major concern with Sputnik was not necessarily the fact that the Soviets were the first in space, but the means in which they got there. At that time, the world was in a race to create the ICBM, or the Intercontinental Ballistic Missile. Once the soviets launched Sputnik with this, the United States and Europe reacted. Within the United States, the primary reaction was fear. Americans feared two things about this new advancement. First off, if the Soviets were able to produce ICBMs in mass quantities, they would be able to attack the rest of the world without any retaliation.

The next shock was Yuri Gagarin on his Vostok rocket. Gagarin lifted off from Baikonur Cosmodrome, Kazakhstan, on April 12, 1961. His mission lasted one hour, 48 minutes, and concluded with a landing in Kazakhstan, approximately 26 kilometers southwest of Engels. Gagarin had completed one Earth orbit, and did so 25 days prior to the first U.S. suborbital manned flight.

The Russian rockets were able to carry a larger amount as the American ones, that was what made projects like the MIR possible.

The Mir Space Station was officially built to conduct studies and experiments of interest to science and the Russian economy. When the Mir program began, the station's lifetime was estimated to be five years. The last crew left the station in August 1999 -- more than 13 years after the first component was launched. The station is still in orbit, and additional missions to the outpost being planned. Crew members have been ferried to Mir using the Soyuz-TM spacecraft and the NASA space shuttle. In all, 43 space travelers have called Mir 'home,' and 59 others have visited for periods of time less than one month. Sixteen space travelers stayed on Mir for multiple long duration missions. The Mir Core, the base unit of the station, was launched on Feb. 20, 1986. It has a mass of 20,100 kilograms, a length of 13.13 meters and a maximum diameter of 4.15 meters. Its pressurized volume equals 90 cubic meters. The solar panels have a total area of 76 square meters. Five modules are attached to the core. The Progress resupply craft ferried supplies to the crews from 1986 to 1989. After that time, an improved Progress-M resupply craft was used. Both types of resupply spacecraft were launched using Proton rocket launch vehicles. They each had a total mass of 7,450 kilograms, a maximum diameter of 2.7 meters and a length of 7.2 meters. The Mir station core and modules were put in orbit by a Proton SL-13 launch vehicle. The SL-13 was designed in 1965 as a more capable follow-on to the two-stage SL-9, although the SL-13 was much larger. Its total mass at the launch of Salyut 6 was 697.1 tons, and its total length was 59.8 meters. Its first flight was in 1968. The vehicle's first stage uses RD-253 engines, which provide 167,000 kgf in a vacuum. All three stages use Nitrogen tetroxide/UDMH propellants. Currently the Russian Aviation and Space Agency is examining Mir to see if it may be salvaged as a private industry research post and galactic retreat for wealthy vacationers. The proposal to resurrect the space station was made in January 2000 by Walt Anderson, a Washington-based venture capitalist, who is said to plan to invest $21 million into attempts to renovate the station.

The Challenger Accident

On the 28.1. 1986 the orbital glider Challenger exploded briefly after the start from the Cape Canaveral. This misfortune could have been avoided. With the explosion the entire crew died: Francis Scobee, Michael Smith, Christa McAuliffe, Gregor Jarris, Ronald McNair, Ellison Onizuka and Judith Resnik died an unnecessary death. The minitioes reconstruction of the incident exposed a brittle rubber seal ring at one of the booster rockets as direct cause of accident: Fuel could withdraw, caught fire and led to the explosion. Of engineers of the manufacturing firm Thiokol of the rockets these gaskets were regarded already longer than weak point, since their elasticity was not sufficient at low temperature for error free functioning. On the eve of the already several times delayed start the different engineers of the rocket manufacturer were, among them the project manager all McDonal and the expert for rocket seals, Roger Boisjoly, against a start. In a telefonkonferenz with NASA they made attentive to the temperature problems of the seals, since for the day of the start low temperatures were expected. NASA and their project manager pointed out that there would be no start restrictions because of certain temperatures, and pushed on the start. The deputy director of the rocket-manufacturing firm Robert Lund followed the doubts of engineers and spoke thereupon with its superior, Jerry Mason (likewise a Engineer). This said in an internal discussion of the rocket-manufacturing firm to R. Lund: ' Take off your engineering has and PUT on your management, ' on which Lund the start release agreed. He told this to the project manager of the NASA, who reported to his boss that Thiokol agreed with the rocket start, without referring however to the doubts of the company. So the accident took its run. Because of the Challenger the American space flight was thrown back for years. Everybody feared that such a thing could happen again.

The Space Shuttle

Shuttle main Components