In 1997, Americans launched two space probes (探测器). They were ________ Voyager I and Voyager Ⅱ. They sent ________ photos and facts about the more distant planets. Now they are traveling out in the galaxy (星系). Here are some facts about the Voyager spacecraft.

The total cost of the Voyager mission (任务) is 865 million dollars at that time. This ________ very expensive. But it is only twenty cents for each American each year.

The television cameras of the Voyager are ________ powerful that they could read a newspaper headline (报纸标题) at a distance of one kilometer. But in fact there aren’t any newspapers in ________!

Scientists have put a message on the Voyager spacecraft. We hope that someone will find it one day. But it will ________ the Voyager 40,000 years to reach another solar system like ours, with planets. The ________ is on a special disc (盘), a bit like a CD. The disc has sounds and pictures on it. There are thirty-nine sounds of the earth. Some of them are ________ sounds, such as the sea, wind, and thunder (雷声). Some are animal sounds, such as birds, dogs, and humans. Some are man-made sounds, like machines, buses, and trains. They also put on music from many different countries in the world. ________ there are spoken greetings from earth-people in fifty-five languages. There is a message in English from the president of America. There are also 116 pictures of the ________ and its people.

It often takes astronauts days to go to the moon. But will people live there? Will people ______ a city on the moon?

Some people think it is ______ . But it won’t be easy. There isn’t any oxygen (氧气) on the moon. Spaceships will need to bring oxygen from the earth. ______ will be a problem, too. How will people ______ vegetables? There isn’t any water,   ______ scientists think that they might find some ice. The energy (能量) for the city won’t be a problem—it will   ______ the sun.

Who will go to the moon? Maybe ______ will go there. The moon is an interesting place for them. It is never cloudy or rainy on the moon, so it is a good place to study (研究) the ______ and planets. Maybe we will build a university for them. We will ______ build a hotel for visitors, too. There are no beaches on the moon, but people can walk on the moon and take photos of the earth.

Will it ______? Maybe. But one thing is true: A visit to the moon hotel will be very expensive!

The first astronauts

Since the earliest times, people have looked up at the stars, the moon and the planets. Today people use modern machines _______ at the sky. This is very different from the situation _______ years ago when people could only use their eyes. Perhaps they dreamed of _______ the universe. When did humans first go into space? The story began not so very long ago, _______ the first astronauts were not people-they were animals.

Scientists wanted to make travelling to space as _______ as possible for humans. So they decided to experiment with animals and, test _______ in spaceflights. Insects, mice, frogs, dogs and monkeys were some of the animals _______ first went into space. Many of them _______ , but they helped to make space travel safer for humans. For their great service, we _______ forget these animals.

Albert I was the first monkey to go into space in 1949. Sadly he died ________ his spaceship landed back on Earth.

________ the result was different for Ham the Monkey. His story ended happily when he returned to Earth ________ very good health.

Scientists wanted to know the answer to the important question: could ________ animal like Ham do the same things in space as he could do on Earth? The answer came when Ham ________ into space in 1961. Yes, he did everything well and lived for ________ 16 years.