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The cover picture above shows an approach for space flight to the Moon. The type of space craft drawn determines whether the mission is to land or simply orbit the Moon. Find the hidden buttons to understand what type of mission is shown.

Besides mistakes revealed by hidden buttons, others exist in the picture. For example, the ships have three rocket engines for propulsion, but where are the small rocket thrusters for steering the ships? By unequal throttling of the two outside engines, the spacecraft could be steered to the right or left which is known as "yawing" the craft. In order to steer the ship up and down or "pitching" the spacecraft, two more engines, one above and one below the center main engine would be needed.

The spacecraft shown at left could not enter Earth's atmosphere like the space shuttle. Though the tails which are shown would help the craft fly through the atmosphere, there are no control surfaces called aerolons to provide steering. Aerolons act like a boat's rudder, using the air streaming past an airplane to steer the aircraft. No control surfaces are shown in the drawing at left. The people would need another type of spacecraft to return to Earth.


1. Redraw the ships at left to enable them to fly in Earth's atmosphere and steer in space.

How Men Landed on the Moon

(Note: Click on the other spaceships pictured at left and read about going to and returning from the Moon before reading the following description of how men landed on the Moon.)

The first men to walk on the Moon were Americans. On the 20th of July 1969, the first man from Earth set foot on the Moon. His name was Neil Armstrong.

The craft that made the journey to the surface of the Moon possible was called the Eagle. The Eagle was specially designed to carry men from lunar orbit to the Moon's surface and back to lunar orbit. Its most important parts were a rocket stage for descending to the Moon's surface, a rocket stage for ascending from the Moon, and a crew compartment providing air to breathe and controls to pilot the lunar lander. Other parts included a steering or guidance system, landing gear, experiments to place on the Moon, a car to drive around the Moon, and food and water for the two man crew.

The mission which landed on the Moon was called Apollo 11. It used the same three stage Saturn 5 rocket which took men on an orbit around the Moon in December of 1968, but it also included the landing spaceship called Eagle which was attached to the crew's command modul and service module.

The craft entered lunar orbit after a retro-burn of the service module's engine which slowed their velocity enough for the Moon's gravity to capture them in a lunar orbit. The lander separated from the command ship. One crew member remained in the command module orbiting the Moon. After separating from the command module, the lander's descent engine fired in a retro or reverse direction from descent. This slowed the velocity of the vehicle causing the craft to descend to the Moon's surface as a result of the Moon's gravity drawing the craft downward. As the lander approached the surface, the descent engine was throttled in a retro-burn so that the lander made a gentle "touchdown" with its four footed landing gear on the Moon. The force of the descent engine's thrust counter-balanced the weight of the lander in a way that would permit the crew in Eagle to make a soft landing on the Moon.

After exploring the Moon, the crew of Neil Armstrong and Edwin Aldrin, re-entered the Eagle and fired their ascent engine. The thrust of the ascent engine separated the ascent stage from the descent stage which remained on the Moon. As the ascent engine continued to burn, the ascent stage gained velocity and altitude to achieve lunar orbit in order to reach the Command Module for the trip back to Earth.


1. What would happen if the descent engine ran out of fuel before reaching the Moon's surface?

2. What would happen if the ascent engine ran out of fuel before meeting the command module?

How Men Got to the Moon

Since the first men and women, boys and girls looked up into the night sky and saw the bright image of the Moon, they have imagined how they might travel from Earth to the Moon. Some early hunters might have aimed a bow and arrow at the Moon, drew back the bow string and released the arrow launching it on a journey toward the Moon. Simply firing a gun's bullet, or bow's arrow at the Moon does not mean the bullet or arrow will eventually reach the Moon. The force of gravity pulls the bullet and arrow back to Earth.

During the mid 1800's, a man named Jules Verne wrote a story about a cannon whose shell could carry passengers on a journey to the Moon. The story was not true, but the idea was very interesting and caused many people to think about other ways of reaching the Moon.

By December of 1968, Americans had built a rocket whose power was enough to launch a spacecraft and its three passengers on a trip around the Moon. The mission was called Apollo 8, and its commander was astronaut Frank Borman.

The launch rocket was called the Saturn 5. The Saturn rocket was really a stack of three separate rockets. The first rocket was called the S-I stage. It had five huge engines. It was the most powerful of the three stages. When its engines had burned for several minutes, it separated from the remaining two rocket stages. Then the next rocket stage ignited thrusting itself, the last stage, and the three man crew module still higher above Earth toward orbit. Without the heavy mass of the first stage which had been cast off, the second rocket was able to go much faster. Finally, when it had expended its fuel, it, also, separated, and the final stage rocket ignited placing the spaceship in orbit around the Earth.

The third stage of the Saturn rocket was called the S-Four-B or S-IVB. It was slightly different from the first two stages because its engine could be stopped and started. The other engines were designed to burn until all their fuel was spent. After the S-IVB stage orbited the Earth attached to the crew module, it was restarted. The rocket engine of the S-IVB provided the thrust force to place the crew capsule on its journey to the Moon. After sending Frank Borman and his crew on their journey to the Moon, the S-IVB stage was also discarded.

The rocket pictured at the left is unlike the S-IVB rocket described above. SPACE SHIP TO THE MOON shows a rocket which cannot be separated from the crew module. Also, the members of the crew shown at left number many more than three people. The S-IVB rocket had only one engine, not three as shown in the picture. Also, the actual Apollo rocket had much bigger fuel tanks than shown in the SPACE SHIP TO THE MOON picture.


1. Without enough fuel to reach the Moon, what would happen?

2. Do you think the ships pictured at left were attached to other stages? Explain.

How Men Returned from the Moon

After the Apollo 8 spacecraft and crew had orbited the Moon many times (December of 1968), it was time to return to Earth. (Note: If you have not clicked on the space ship shown at left on its journey to the Moon, do so now and read the information about the trip to the Moon.) Besides their crew module called the command module, another module known as the service module accompanied them on their journey. The service module attached to the rear of the command module and provided the crew's electrical power, water, and oxygen on the journey to the Moon and back to Earth. Besides "life support" supplies the service module had an engine at its rear called the service propulsion system or SPS.

The SPS engine's purpose was to provide the thrust needed to slow the spaceship as it approached the Moon by doing a retro-burn. A retro-burn is the firing of an engine in the opposite direction of the path of the spacecraft. A retro-burn slows the velocity of the spacecraft. By slowing the spacecraft, the force of the Moon's gravity was able to capture the orbit of the Apollo 8 crew's spaceship so that it would orbit the Moon continually.

The SPS can be started and stopped. A second purpose of the SPS was to provide enough thrust to break free of the Moon's gravity and rocket the Apollo 8 crew back to Earth. The SPS was successfully fired enabling the crew to start their journey toward Earth.

When the moonship returned from the Moon and approached Earth, the crew compartment known as the command module separated from the service module. This was an important event in safely returning the three astronauts to the surface of the Earth. When the service module was cast off, the command module's heat shield was exposed and ready to shield the Command Module from the high temperature of reentry. Only the command module was able to reenter the Earth's atmosphere. Its heat shield is specially designed to remove the heat caused by the friction generated by the high speed of the spacecraft rubbing against the air modules of the Earth's upper atmosphere. Without the shield, the spacecraft would be destroyed. After the descent of the command module is slowed by the friction of air, parachutes are released which gently bring the crew to an ocean landing inside the command module spacecraft.


1. How does the spaceship shown at left differ from the Apollo 8 spacecraft?

2. What would happen to the spaceships at left if they tried to reenter the Earth's atmosphere the same way that Apollo 8 was designed to reenter?

3. How do you think the ships at left were designed to reenter the Earth's atmosphere?

4. How do you think the ship's at left could land on the Moon?

5. Would the fins on the spaceships at left help them land on the Moon? On Earth? Explain your answer.

6. Could the Apollo 8 spacecraft land its crew safely on the Moon? Why or why not?

Junior Astronauts

The first people in space were adults. Why do you think adults were chosen instead of children? Let's look at the requirements a person had to meet to be picked as one of the first American astronauts. An astronaut had to be a citizen of the United States. He or she could not be older than 35 years of age nor, if possible, taller than six feet in height. These requirements would not exclude children from serving as astronauts.

In addition, the first astronauts had to be either pilots or scientists. They had to have studied engineering or another science. Next, they must have pursued graduate work after college and been outstanding in their classwork.

Think about these educational requirements. It is not likely that a young person the age shown in the picture at left could have completed college or graduate school education.

Why do you think it is important for astronauts to go to school? The answer is that they must understand how their spaceships and rockets work. Rockets and space flight require knowledge about chemistry, mathematics, physics, and engineering sciences. If you want to become an astronaut, it would be good to pursue education.

One of the biggest benefits of the space program is that it encourages young people to do well in education. Professional athletes become idols to children. As a result, many children practice many hours to become skilled at a sport. The space program's astronauts are like the men and women who have achieved greatness in sports. The best thing children and young people can do to be like their space heroes is to study and continue their education in high school and college.


1. The first manned spaceships did not carry cargo and payloads like the space shuttle does. Now, certain types of astronauts are called mission specialists or payload specialists because they do not command or pilot the spaceship but deal only with space experiments, satellites and payloads. Do you think it is important for them to have an engineering degree? If not, what type of degree(s) should they have? Explain your answer.

While children cannot become astronauts, there are now many opportunities to become "junior astronauts" by attending special space schools and camps designed to train and prepare young people for a future career in the space program. There are Challenger Learning Centers throughout the United States as well as space camps like the famous space camp at the Marshall Spaceflight Center in Huntsville, Alabama. Also, there is the Junior Astronaut Foundation which sponsors space clubs in schools throughout the United States. Rockets clubs and societies offer opportunities for children to learn and experiment with rockets in a safe setting. The educational clubs, societies, camps, and courses available to children and young people are too numerous to list here but likely one is available to any young person in the United States who wants to become a junior astronaut.

2. What opportunities to become a junior astronaut are available to you in your part of the United States or world? (Hint: Call your local elementary school and ask for information about space education.)