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Monday, December 11, 2017

Astrology As in Astronomy

Astrology As In Astronomy


The Sun: It is roughly 93 million miles away and every square yard of surface on it sends 70,000 horsepower streaming out into space. The Sun gets this vast amount of energy from the hydrogen gas within it. The tremendous mass of this star – 335, 000 times that of the Earth – generates gravitational stresses within itself that cause its internal temperature to rise to 10 million degrees. Atoms of hydrogen fuse into the element helium at this temperature. We know that it takes four hydrogen atoms to make one helium atom with a little bit of matter left over.  That matter is transformed into nuclear energy.  Each second, 616 million tons of hydrogen form 612 million tons of helium. The extra four million tons are sent out into space as energy – heat, x-rays, visible light, radio waves, and so forth.

The Sun is not exactly a gas. It is a plasma, a fourth state of matter made up of separated subatomic particles. Its density is about the same as that of molasses.

Not many people know that the Sun rotates on its axis in a way comparable to the Earth. As its middle – the solar equator – it makes one complete revolution in 25 days. In other words, a day on the Sun would be roughly comparable to one hour on Earth. The Sun, as was noted before, also moves through space.

It was only natural that primitive people associated the Sun with the life force. Scientists now believe that it was the Sun’s radiation of many millions of years ago that was responsible for forming the first molecules that carried life. And for 2, 000 years astrologers have equated Sun with the maximum energy that a person invests in being what he is.

Sun and Planets. Illustration: © Elena

The Moon: When astronauts landed on the Moon, they returned with more problems than answers. Our Earth’s sole satellite seemed to have a much more complex nature than had ever been supposed. One of the problems is that some of the rock samples brought back seem to be older than the most ancient rocks of Earth, suggesting that the Moon was formed before the Earth. This has brought back the idea      that the Moon was a wanderer in space until it was captured by Earth, perhaps no longer than ten thousand years ago.

Support for this idea has come from the discovery of mascons, areas of Moon which have an extraordinary density – enough so their gravitational pull can make a spacecraft wobble in its orbit over the Moon. The mascons are thought to be pieces of asteroids or large meteors which slammed into the lunar surface, possibly during a passage through the asteroid belt.

The moon is a little over a thousand miles in diameter and a little less than a quarter-million miles away, as it average distance. Its disc in the sky is exactly the same size as the Sun’s. Thus when the Moon is exactly between the Sun and Earth we see the solar eclipse. A lunar eclipse happens when the Earth is exactly between the Sun and Moon. At that time the shadow of the Earth obscures the Moon’s face.

Eclipses have been regarded with awe since prehistoric times. To traditional astrologers, an eclipse occurring in a given house on a subject’s chart is thought to adversely affect the matters governed by that house. An eclipse in the chart of a country is regarded as a very ill omen by mundane astrologers.
Ordinarily, though, the Moon is associated with mood and particularly with the temperament that molds the personality as it is presented to the environment. As a significator, it refers to portable quantities of money, to mature women in general, and to the wife and mother.

Mercury: The planet closest to the Sun is Mercury, an airless ball of craggy rocks with a sunlight temperature hot enough to scorch this page and a night temperature believed to be 200 degrees below zero.

For a long time astronomers thought that Mercury did not rotate. They believed it always kept the same side towards the Sun. Then radar measurements showed that this was not so. Mercury rotates slowly, three times round on its axis for every two trips around the Sun. It makes that trip around the Sun in 88 days.

Though Mercury is 36 million miles from the Sun, as viewed from the Earth, it can never make any important astrological aspect with it except the conjunction. In fact, just because it is always so closed to the Sun, it is hard to see. The ancient Babylonians said this indicated it was delusive and deceitful and they linked it with dishonesty. As a result Mercury is associated with thievery. Later on, the Greeks tied it in with their messenger-god, Hermes. When Hermes was associated with the Egyptian god of wisdom, Thoth, Mercury also became associated with intellectuality.

Venus: Sentimental astronomers used to call Venus the twin sister of Earth since it is just about the same size and seemed to have a habitable atmosphere. Later explorations by space probes have shown that Venus is nothing like Earth at all.

Nobody knows what the surface of Venus looks like. It is completely covered by clouds. Measurements of the surface temperature by sophisticated instruments reveal that it is hot enough to make wood burst into flame. It is a very dry planet, and the thick layer of clouds that covers it may be frozen carbon dioxide crystals, not water vapor.

Venus is a dark planet because of its heavy cloud blanket, but what light there is would produce unusual optical effects due to the way it is diffracted through the atmosphere. For instance, if you were to stand on a flat plain on Venus, it would seem that you stood on a bowl-shaped depression. You would see an image of yourself further off. Beyond that would be another image. The impression would be akin to that you get by standing between opposed mirrors: an apparently infinite series of smaller and smaller images of yourself.

In spite of its ugly physical characteristics, Venus is still used by astrologers as the correlate of any pleasurable activity – sex, game-playing, dressing up, art-work and spending. As a significator it relates to the nubile woman, the sweetheart, the fiancé. It also stands for jewelry, works of art, and entertainments.

Mars: Venus is 67 million miles from the Sun, about two thirds of the Earth distance. At about double its distance, on the other side of the Earth, lies the planet Mars. That planet is probably the most widely publicized planet in the solar system. This is due to the fact that as long ago as 1877 the Italian astronomer G.V. Schiaparelli thought that he saw canals on it, which implied intelligent thought, so many people speculated on what sort of beings must have built them. H. G. Wells contributed his ideas in War of the Worlds and Edgar Rice Burroughs in his Martian series. For a long time Mars was the darling of the science-fiction writers.

However, in 1965, the space probe Mariner IV sent back 22 pictures of the planet from a distance of 6200 miles. There were no canals. There was only a bleak, cratered surface like that of the Moon. There was one strange thing to be noticed, however. One area, some 400 by 600 miles in extent, showed absolutely no craters at all. Some scientists thought this might indicate an erosion process which had wiped the craters. Considering that the Martian atmosphere is only one percent as dense as the Earth’s, others wonder what that erosion process could be.

As we see it in the sky, Mars has a reddish color. Apparently, this comes from a large amount of iron oxide in its surface. At any rate, for centuries it has been associated with violence, blood, bloodshed, war… The tendency of modern astrologers is to associate it with the masculine principle in nature, with aggression, activity, impulsiveness. It is linked to iron and with anything made of iron, such as tools and weapons.

Asteroid belt: Mars is the last of the group known to astronomers as terrestrial – earthlike – planets. Beyond it and the first of the second group of Jovian planets, lies a band of mystery known as the asteroid belt. Asteroids are relatively tiny planetoids ranging in size from a diameter of 218 miles down to less than a mile. It is believed that there may be as many as 50, 000 planetoids though less than 1700 have actually been studied. For a long time astronomers thought that the asteroids were the remains of a broken up planet or planets. However, since it is apparent that they total less than one-thousandth of the mass of the Earth, it could not have been a very big planet, perhaps even smaller than our Moon. One school of thought is that our Moon, winging in from outer space, received its pockmarked surface, its craters and mascons, when it passed through the asteroid belt on the way to being captured by our gravitational field.

Jupiter: Beyond the asteroids, at a distance of nearly half a billion miles from the Sun, is the planet Jupiter, a body so great that it is larger than all the other planets put together. In recent years, more and more have been discovered about Jupiter, even though not much is known about is actual physical structure. It is covered by an atmosphere of gases which may be 2500 miles deep. Whether it has a solid core or not is still debated. Judging from what is known of its mass – only one tenth of what it should be if it were entirely solid – there may be a solid core in a thick atmosphere of hydrogen, helium, methane and ammonia. The presence of methane and ammonia is interesting to astronomers because they believe that once the Earth had the same sort of atmosphere and its molecules were ordered by solar radiation into substances that would support life.

One of the strange things about Jupiter is that it gives off more energy that it receives from the Sun. The reason for this is not known. It also emits radio waves, a point of interest to some amateur radio operators on Earth who are able to pick them up with relatively simple equipment. The messages do not spell anything, however. In the southern hemisphere of Jupiter there is a patch known as a “great red spot”.  It is 25, 000 miles long and about a third of that in breadth. It remains one of the more obscure mysteries of the planet; doubly so in the past few years, because it seems to be moving. Jupiter has 12 moons. The largest, Ganymede by name, is larger than Mercury, and astronomers have observed that it has an atmosphere, the only planetary satellite that does.

Saturn: Saturn is nearly ten times the diameter of Earth, but its density is less than that of water.. It has been remarked that if an ocean of adequate size could be found, Saturn would float in it.
The main identifying characteristic of Saturn is its system of rings. These appear to be solid when viewed at an angle, but disappear when viewed edgewise. This suggests that they are composed of fine particles of dust, the remnants of a destroyed satellite, which whirl around the planet in orbit. Saturn’s composition seems to be similar to Jupiter’s.

Saturn’s slow movements across the skies were remarked by the ancients who viewed him as an old man and equated him with the autumn of life.

The Greeks called him Kronos, the god of time. The Romans knew him by his present name. Astrologers consider that his basic principle is exactly opposite to that of Jupiter. Instead of expansion, he relates to whatever restricts or restrains.

Uranus: There was a flurry among both astronomers and astrologers when Uranus was discovered in 1781. For 2000 years it had been believed that there were only seven bodies in the solar system and astrologers had quite a job working Uranus into their scheme.

Uranus remains mucho of a mystery because it is so far away – 1, 7 billion miles from the Sun – but it seems to have a composition similar to Jupiter and Saturn. It makes a complete circuit of the Sun in 84 years, but spins so fast that its day is only 11 hours long.

The most unusual thing about Uranus is that it is lying on its side. Its equator passes through the points where its north and south poles ought to be. For some reason, Uranus was early associated with revolution and political independence. It has also mysteriously been linked to the brotherhood of man. Actually to the modern astrologer, it relates to sudden and disruptive action. With Mars, it makes a good significator of a gun-shot wound or automobile crash, but with Venus it can mean an impetuous love affair.

Neptune: Neptune was discovered 65 years after Uranus at the beginning of public interest in spiritualism. For this reason it is often referred to in 19th century mystical literature as a spiritual planet. Neptune is smaller than Uranus, about three and a half times the size of Earth, but it is nearly three billion miles from the Sun. It cannot be seen with the naked eye. Its constitution appears to be t

The same as the other Jovian planets – a thick atmosphere of gases, mostly frozen, with a relatively small central core. It has the fourth largest moon in the solar system – Triton, a body 2500 miles in diameter.

The meaning of Neptune to the modern astrologer is the element of unreality – dreams, narcosis, fraud, deception. It is the significator of paranormal phenomena.

Pluto: In 1930, Clyde Tombaugh discovered the planet Pluto. It is 3, 7 billion miles from the Sun and very little has been discovered about it during the first fifty years. Most of astronomers think today that it is not a planet at all, but a moon of Neptune that has slipped out if its orbit. Pluto is more like terrestrial planet than a Jovian one. Its mass has been calculated to be only one-fifth of Earth or not much larger in mass weight than our Moon.

Astrologers worked for a long time before they were able to arrive at any conclusion as to what Pluto stood for. It seems to relate to a fierce intensity of purpose, a working-in-darkness with surprising results, eruptively presented. With Mars, Saturn, or Uranus in combination, Pluto can relate to great public disasters such as wars and earthquakes. The destruction with which it is associated is always followed by a rebuilding.

Those, then, are the bodies of the solar system that are used by astrologers for making up their charts. Whether the physical characteristics of the planets correlate with astrological phenomena is a moot point. But certainly the points of space that they occupy in the solar system have a significance that lends itself to a reasonable interpretation.

What Keeps a Satellite Up?

What Keeps a Satellite Up?


Before we answer this question, we should first make sure we know which way is up.  Since the planet Earth is round, up means any direction that is away from the center of the Earth. And if we are talking about the planets, which are satellites of the Sun, up means any direction that is away from the Sun. Whatever keeps a man-made satellite up is the same thing that keeps the Moon from falling on the Earth and the Earth from falling into the Sun.

Now, if you had a ladder about 200 miles high, and if you climbed up to the top carrying a satellite under your arm (some satellites are small enough to carry under your arm), and let go of it, it would fall down exactly as you had dropped it off the top of a building. It wouldn’t stay up at all. So it isn’t just a matter of getting a satellite up there.

What does keep a satellite up is its velocity – the right amount, and in the right direction. And that leads us to Newton’s law stating that every action has an equal and opposite reaction. Newton has another law that states that anything that is moving will keep on moving at the same speed in a straight line forever, unless some force makes it do something else. This means that if we used a rocket to launch a satellite from the earth’s surface, would like to keep going in the same direction it had when the rocket burned out, and at the same speed. And in fact, if the earth were not there, that is just what it would do. But the Earth is there, and the Earth’s gravity is the outside force that makes it do something else. We have a tug-of-war, where the satellite is trying to sail off in a straight line into space and the Earth is trying to pull it back down.

Photo: Elena

Now if the satellite is going fast enough it will break loose from the pull of the Earth and sail off into space (but not in a straight line, because then the Sun’s gravity will start trying to pull it in toward the Sun). But if it is going just fast enough to balance the pull of the Earth it will keep going around the planet as though it were on a leash; it keeps trying to go straight and the leash (gravity) keeps pulling it in. That is what the Moon – our biggest and oldest satellite – has been doing for millions of years.

The force of gravity gets smaller and smaller as you get farther and farther from the Earth (that’s another of Newton’s laws). This means that for any distance from the Earth there is one particular speed that just balances the pull of gravity, and the higher a satellite goes (that is, the farther from the Earth), the less speed it needs to stay up. On the other hand, you need a more powerful rocket to get it there, because the rocket has to push it farther against the pull of gravity. And if a satellite is at a lower orbit, it has to be going faster just to hold its own against the pull of gravity. That is why lower satellite orbits have shorter periods of revolution – time it takes to go around the Earth – than higher ones.

Jupiter and its satellites. Photo in public domain

The first astronauts in their Mercury capsules went around the Earth in about an hour and a half. They were only a hundred miles up. And they were going over 17,000 miles an hour. The Moon, though, is 240,000 miles up and takes 28 days to go around the Earth. That means it goes only about 2200 miles an hour. For any altitude in between, there is a particular speed that you must go to stay in orbit at that altitude.

Of course, if the satellite or even the Moon were to stop in their orbits they would fall straight down to Earth. And if anything slows a satellite down it will fall a little bit because now the force of gravity is stronger than the force trying to keep it going in a straight line. Like anything else that falls, it will speed up as it falls until once again it is going fast enough to maintain a new orbit at the lower altitude. That is how the Gemini astronauts changed from one orbit to another. If the wanted to go to a lower orbit they fired their retro motors to slow them a little bit.

The process is just the reverse if you want to change from a low orbit to a high orbit.  You give a spacecraft a short push with your rocket motors, and that starts it moving up to the higher altitude. As soon as the motors stop thrusting, however, the spacecraft just coasts the rest of the way until it gets as high as it can go with the amount of thrust. While it is coasting, of course, it slows down, like a car that is coasting uphill after you shut off the engine. And if you’ve given it the right amount of thrust, when it gets to the higher orbit it will be going at the slower speed that corresponds to that orbit.

So although you speed a satellite up to get it to a higher orbit, by the time it gets there it is actually going more slowly than before. And although you slow a satellite down to get it to a lower orbit, by the time it gets there, it is actually going faster than before.

You already know that a satellite has to be lifted above the Earth’s atmosphere to stay in orbit at all, because it had to push its way through the air while it was in orbit, it would slow down so soon that it could stay up for only a very short time. Illustration: Megan Jorgensen.

Propellants

Propellants


Today`s rocket engines use chemical propellants, which may be either liquid or solid. Notice that we say “propellants” and not “fuel”. This is because a rocket engine usually has to have two propellants. One is called fuel and the other is called the oxidizer. An automobile engine or an airplane engine needs to carry only fuel, because it uses the oxygen from the air to burn with the fuel. But most of the time a rocket has to operate where there is no air, so it must carry its own source of oxygen, and that is called the oxidizer.

Most liquid rocket engines have separate tanks for the fuel and the oxidizer, which are combined and burned in the combustion chamber of the engine pretty much the way gas and air are combined and burned in the burner of an ordinary gas stove. The difference is that in the rocket engine both fuel and oxidizer are stored in liquid form in the tanks and pumped or gravity-fed to the combustion chamber, where they are sprayed in and burned.

Different rocket engines use different combinations of fuel and oxidizer, but the most common oxidizer is just plain liquid oxygen. In the Atlas and in the Saturn V first stage, the fuel used is kerosene, very much like jet airplane fuel. For upper stages like the Centaur or the third stage of the Saturn V, liquid hydrogen is used as the fuel. Both oxygen and hydrogen have to be very cold to become liquid (-297 degrees F for oxygen and -423 degrees F for hydrogen), and are hard to store and handle. These propellants are called cryogenic, from the Greek word kryos, meaning icy cold.

And remember that even the most efficient rocket engine works on the same principle as the toy balloon, that is, it must expel something from the nozzle in order to create thrust. Photo: © Elena

The Titan II rocket and some others used propellants that did not have to be cold, such as hydrazine and nitrogen tetroxide or nitric acid. Some liquid propellant combinations are called hypergolic, which means that they ignite just by coming together and therefore do not need any ignition system. The TRW-built Descent Engine for the Apollo Lunar Module used hypergolic propellants.

A solid propellant engine also has a fuel and an oxidizer, but they are mixed together before-hand and poured into the rocket casing. The rocket case is placed nose down and a core is placed in the middle of it. The mixture is then poured in around the core and cured by heating until it becomes a solid rubbery mass. The core is then taken out, leaving a hole in the middle of the propellant. When it is time to fire the engine, an igniter shoots a tongue of flame down this hole and the propellant burns all along this inner surface, shooting the hot gases out the nozzle.

Solid-propellant rockets have no tanks or pumps or valves and are very simple and reliable. The Minuteman missile, for example, has three solid propellant stages and a ready to take off ant time at less than a minute`s notice. One trouble with a solid rocket, however, is that once you have started it you can`t shut it off as easily and safely as you can a liquid engine. Also, we haven’t perfected a way yet to fire it, shut it off, and then start it again later as we sometimes need to do for space missions.

Another type of rocket that will be used to power the deep-space missions of the future is the nuclear rocket. The first such engine was designed by NASA and the Atomic Energy Commission. It was called NERVA (Nuclear Engine for Rocket Vehicle Application). It was supposed to use the heat from a nuclear reactor to heat liquid hydrogen to a high-temperature gas, which was then expelled out the nozzle like the gases from a chemical rocket engine. The Isp from such an engine is much higher than that of chemical propulsion; it would be about 1000 seconds, compared to 300-500 seconds for chemical propellant rockets.

Still more advanced is the electrical propulsion engine, which has much higher Isp`s. This engine uses electricity to heat hydrogen to a high-temperature gas that is expelled from the nozzle. So far, only relatively small electrical propulsion systems have been built, because it is hard to generate in space the enormous amounts of electrical power that would be needed to produce a thrust comparable to that of a chemical or nuclear rocket engine. The ion engine and the plasma engine are other types of electrical propulsion system that are also very efficient, but so far they too are limited to very small thrusts of a pound or less.

Notice that electricity by itself could not propel a rocket at all. It can make the rocket move only by accelerating some kind of particle and expelling it.

What Makes a Rocket Go

What Makes a Rocket Go


The force which propels rockets, called thrust, has often been demonstrated with an ordinary toy balloon. If you suddenly release a blown-up balloon, the air inside will rush out its open neck. Obeying Sir Isaac Newton`s law which states that every action sets up an equal and opposite reaction, the rushing air creates a reaction force – thrust – which drives the balloon in the opposite direction.

Just as a balloon is thrust forward by expelling air, a rocket is thrust forward by expelling particles – usually in the form of a gas – from its nozzle. The greater the flow rate through the nozzle, the greater the forward thrust.

Notice that the forward motion of the balloon is not caused by the air expelled pushing against the atmosphere, the way an airplane propeller does. Even if there were no atmosphere to push against, the balloon would still zip around the room. In fact, it would even go a little farther and faster, since it wouldn`t have to push its way through the air.

Thrust is measured in pounds. In order to launch a rocket from the ground, the number of pounds of its thrust must be greater than the number of pounds it weighs. It`s like a tug-of-war between Earth`s gravity and the rocket engine`s thrust: if the engine can push up (thrust) more than gravity is pulling down (weight), the rocket will move up.

An ordinary balloon can be used to demonstrate thrust. Photo: © Elena

How rapidly the rocket moves up depends on how much greater its thrust is, compared with its weight. Rocket engineers call this the thrust-to-weight ratio.

The Saturn V moon rocket, for example, together with the Apollo spacecraft, weighted about 6 million pounds. The thrust of the first stage engines was 7, 5 million pounds, so the engines could win the tug-of-war and the whole vehicle lifted off. The thrust-t-weight ratio in this case was 7, 5 (million pounds of thrust) to 6 (million pounds of weight). This is the same as 5 to 4, or we could say 1.25. That means that the thrust is 1.25 times the weight.

Now you can see that if the thrust were 2 or 3 times the weight it would move even faster. Well, that is what happens as the rocket starts to move. The thrust remains the same, but since the engines are burning up propellants very fast (in the case of the first stage of the Saturn V, 15 tons every second), the weight is getting smaller all the time. That is why the rocket moves slowly at first but accelerates very fast and is usually out of sight in two or three minutes.

Another important factor is specific impulse, which we usually writ with the symbol Isp. To the rocket engineer, this means the same kind of thing as miles per gallon; it tells him how much thrust he can get from a pound of propellants. For example, if he says that a certain type of engine will give him an Isp of 300 seconds, he means that I pound of propellants will generate 300 pounds of thrust for 1 second, or 1 pound for 300 seconds, or some other combination of thrust and time that can be multiplied together to make 300. Naturally he wants to get the most thrust he can from each pound of propellant weight, so he likes the Isp to be as high as possible.

One more very important thing that is considered in rocket design as the mass ration. That simply means the total weight of the rocket loaded with propellants compared with the weight left after the propellants have all burned up. We like to have the mass ration as high as possible, because that means we get more payload placed in orbit, or we can place the same payload in a higher orbit. In order to improve the mass ration, rocket engineers often design rockets with more than one stage, because in this way they can throw away part of the weight when they don`t need it any more. When the first stage has burned up all of its propellants, it is separated and allowed to fall back to the ground. The the casing, tanks, engines, and so on for this stage don`t have to be carried up any higher. Most rocket vehicles have two or three stages.

Rocket Technology

Rocket Technology


In the beginning, the growth of rocket technology in the U.S. received an enormous impetus from the development of the Air Force`s long-range missiles. These programs – Atlas, Thor, Titan, and Minuteman – representing one of the most urgent, complex, and costly tasks ever undertaken by American industry, involved over 200,000 firms as well as many hundreds of thousands of scientists, engineers, and technicians. Selected by the Air Force as systems engineer and technical director, TRW Systems Group coordinated the technical, cost, and schedule aspects of each of these vast efforts.

Atlas

Atlas, the first U.S. ICBM, was a 1-1/2 stage cryogenic liquid-propellant missile featuring a sustainer engine and two booster engines. The two boosters, visible on each side of the rocket, were jettisoned in flight, leaving the sustainer engine to continue firing until it burned out and the correct ballistic trajectory was achieved. This is why Atlas was called a 1-1/2 stage rocket, it did not truly have a second stage. The reason for this design was that rocket engineers had not completely solved the problem os starting a second stage engine at high altitudes.

The initial flight was made at Cape Canaveral in June of 1957, only a little over 2-1/2 years after development had begun. Athough deactivated in 1965 as a weapon system, Atlas continued to play an active role in the space program for a few years, having served as a versatile and reliable booster for lunar and deep space probes as well as for Project Mercury and Project Gemini, as engine improvements increased its thrust to over 400,000 pounds. Mated with an Agena D upper stage, this vehicle was able to insert in earth orbit a payload of 11,500 pounds.

Minuteman I. This image or file is a work of a U.S. Air Force Airman or employee, taken or made as part of that person’s official duties. As a work of the U.S. federal government, the image or file is in the public domain

Thor

The intermediate-range Thor, a one-stage cryogenic liquid-propellant missile, took just 13 months to go from drawing board to first flight. It was ready for military operation as an IRBM in December of 1958, just 3 years after starting development – a record for such a vast undertaking. Mated with second and third stages derived from the Navy`s Vanguard booster and dubbed Thor-Able 1, the vehicle saw its first service in the nation`s space effort in August of 1958. In October of the same year, it launched TRW`s Pioneer 1, the world`s first deep space probe. Deactivated as a weapon system in 1963, the Thor became the nation`s most widely used space booster, earning the title of “space-age workhorse”.

It was used with several different upper stage combinations, and was upgraded almost continuously. The early Thor-Delta configuration, based on the original Thor-Able combination, was able to orbit 610 pounds. One of the last improvement in payload capability was seen in Long Tank Thor, which with its three strap-on solid propellant boosters and an Agena D upper stage was able to orbit 2640 pounds.

Titan

The Titan program resulted in the development of two weapon systems: Titan I and Titan II. Titan I, a two stage cryogenic liquid propellant missile with first stage thrust of 300,000 pounds and second stage thrust of 80,000 pounds, was first successfully flight tested in February of 1959. Like Atlas, Titan I was deactivated in 1965. The later generation Titan II employed non-cryogenic storable propellants and inertial guidance. With first stage thrust increased to 430,000 pounds and second stage thrust to 100,000 pounds, it offered greater payload weight and increased range, as well as better accuracy.

It could also be launched from underground silos, providing greater security against attack. Still deployed and fully operational as ICBM, Titan II also saw duty in the US space program, notable as the booster for the two-man Gemini capsule. Utilizing various improvements to increase thrust, Titan II evolved into an even more powerful vehicle Titan III. One member of this family, the Titan IIIC, featured two 1,2 million-pound-thrust solid propellant boosters, strapped on each side, an improved first stage with thrust increased to 474,000 pounds, and a 16,000-pound-thrust hydrogolic fueled third stage known as a Transtage. Used extensively as by the Air Force as a booster for military communication satellites, TRW`s Vela nuclear detection satellites, and other spacecraft, the Titan IIIC had sufficient thrust to orbit 25,100 pounds.

Minuteman

Studies begun in 1957 to develop a second-generation ICBM which would have less vulnerability to enemy action, be capable of launching in a shorter time, be more mobile and reliable, cost less, and require fewer operating personnel. The ensuing program resulted in the development of the three-stage Minuteman, the first solid-propellant IVBM to become operational in the US. The first version of the missile, Minuteman I, was test-flown from Cape Canaveral in 1961, and later the same year was first launched from an underground silo. The first two flight units (20 missiles) were declared operational at Malstrom AFB, Montana, in 1962.

An improved version, Minuteman II, was first launched in 1964. It incorporated a new second stage engine and an improved guidance system, providing greater range and payload and greater ability to withstand the effects of enemy attack. In 1967, the goal of 1000 operational Minutman was reached.

Development of the next version of the missile, Minuteman III, began in 1967. Minuteman III had an improved third-stage engine and a new re-entry system which allowed even heavier payloads and greater accuracy. A key feature of the new design improvements was their ability to be grafted onto Minuteman II missiles. This resulted in a new weapon system at a fraction of the cost of developing an entirely new one. Dispersed in hardened underground silos throughout seven western states, that prime deterrent force was steadily being updated with the eventual goal of replacing all older models with Minuteman III.