Lesson 9 Space Elevator

(Part 1)
“If I were an astronaut, I could go into space.” Many of us dream of traveling in space, but it is difficult to become an astronaut. However, we should not give up our dream. A new type of scientific technology may take us into space more easily. It is called “the space elevator.”
Shuichi Ohno, the president of the Japan Space Elevator Association (JSEA), said, “Just like traveling abroad, anyone will be able to ride the elevator into space.” This is not just a science fiction story. According to the JSEA, the space elevator will become a reality by the middle of this century.

(Part 2)
How can we build the space elevator? First, a satellite will be launched up to about 36,000 km above the Earth. Then, a cable will be stretched down from the satellite to the Earth’s surface. When the elevator is attached to the cable, it can climb up and down along it.
How long will it take to go into space on the space elevator? With electricity, the elevator will run at 200-300 kilometers per hour. Therefore, the elevator will take 20-30 minutes to go into space, 100 km above the Earth. In order to reach the satellite, the elevator will take about one week. If linear motor technology is used, the travel time will become much shorter.

(Part 3)
The space elevator needs an extremely long cable. It must be about 100,000 km long. That is about eight times as long as the Earth’s diameter. Also, it must be more than 100 times as strong as steel, because such a long cable is easy to break. No one could find a material for such a long and strong cable. It had been the biggest problem.
However, Dr. Sumio Iijima, a Japanese scientist, found the best material for the cable in 1991. It is called a “carbon nanotube.” Carbon nanotubes are about 50,000 times as thin as your hair, and 100-150 times as strong as steel. They are still too expensive because they can only be produced in tiny amounts. Now, researchers are looking for a way to make a lot of them easily.

(Part 4)
Today, we use rockets to go into space. They need a lot of fuel and produce carbon dioxide. On the other hand, the space elevator is much more energy-saving and eco-friendly than rockets. It will use a lot of electricity to go up, but it can produce electricity when it comes down. That electricity can be used when the elevator goes up again. Also, unlike rockets, the space elevator itself will not produce any carbon dioxide.
With this technology, it seems that space travel is no longer a dream. Scientists also think that the space elevator may become a gateway to other planets. Imagine you go into space on the space elevator, change to a space ship, and start on a journey to Mars or Jupiter. Such an exciting experience may be waiting for us!




Lesson 9 宇宙エレベーター

(Part 1)

(Part 2)

(Part 3)

(Part 4)