Step by Step 3000 第2册 Unit11:Space(3)

Part 3. Compton Gamma Ray Observatory.

Keywords. ailing observatory, orbit, gamma rays.

Vocabulary. debris, thruster, gyroscope, bathe, stream from, Compton Gamma Observatory, Goddard Space Flight Center.

Now listen to a news report, complete the news summary and briefly answer the questions you hear.

Space Agency NASA forced an ailing observatory to fall from orbit and crash into the Pacific Ocean on Sunday.

NASA engineers picked a remote spot to avoid deaths and injures from the falling debris.

NASA says the Compton Gamma Ray Observatory has made a fiery plunge through the atmosphere into an isolated area of the Pacific.

Most of the nine-year-old satellite was to have burned up in the dive,

but about six tons of hot metal were expected to have showered onto an isolated area about 4,000 kilometers southeast of Hawaii.

NASA had estimated that the debris would scatter over a long, narrow path, 4,100 kilometers long and 26 kilometers wide.

The deliberate crash came after Goddard Space Flight Center technicians directed the observatory early Sunday to fire its thrusters twice to dive into the atmosphere.

NASA felt this was necessary because one of the Compton's three stabilizing gyroscopes had failed in December.

The Space Agency decided to bring the 16-metric-ton back now in a controlled manner

to prevent possible further system failures from causing it to drop on a populated area.

The Compton's path took it over many populated areas, including Mexico City, Bangkok and Miami.

Compton exceed its original 5-year mission by 4 years, resulting in about 2,000 scientific papers.

The observatory changed astronomers' view of the heavens after showing that the entire universe is based in the invisible gamma rays, but the highest energy form of light.

It discovered hundreds of previously unknown sources of gamma rays, some streaming from black holes, exploding stars and the Sun.

Questions.

1. How old is the Compton?

2. How heavy is the Compton?

3. How many tons of hot metal were expected to plunge into the Pacific?

4. What is the place that has been chosen for the crash of the Compton?

5. How big is the path that debris of the Compton would scatter over?

6. Why is it necessary to force the Compton to fall from its orbit?

7. What's the significance of the Compton?