As you are reading this story, there are a lot of things flying through space. These things are called space junk (太空垃圾).
Space junk comes from many different kinds of things such as old spaceships. These things travel very fast in space.
According to NASA, there are about 500,000 pieces of junk in outer space. Some of these pieces of junk are traveling as fast as about 28,163 kilometers per hour. This can be even faster than a spaceship. Even a small piece of junk can destroy(毁坏) a spacecraft or satellite.
Luckily, NASA has found a way to solve this problem. It made a special satellite called Nano Racks-Remove Debris. The satellite looks like a cube(立方体). It works by collecting small pieces of space junk. There is a 3-D camera on the satellite. It can find where the space junk is, how big it is and how fast it is moving. When it gets close to the space junk, it uses a net to catch it. Later, the satellite burns the space junk in Earth’s atmosphere (大气层).
1.Where does space junk come from?A.Outer space. | B.Things like old spaceships. |
C.Nano Racks-Romove Debris. | D.Earth’s atmosphere. |
A.500,000 | B.28,163 | C.13,00000 | D.28268 |
a. It collects small pieces of space junk.
b. It uses 3-D camera to find the space junk.
c. It burns the space junk in a spaceship.
d. It uses a net to catch the space junk.
A.bcd | B.acd | C.abd | D.abcd |
A.The location of the space junk. | B.The size of the space junk. |
C.The color of the space junk. | D.The speed of the space junk. |
A.Some space junk may travel faster than a spaceship. |
B.There isn’t much rubbish in space. |
C.It’s impossible for a small piece of junk to destroy a satellite. |
D.The special satellite made by NASA works by collecting large pieces of space junk. |
同类型试题
y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2