Zhurong, China’s first Mars rover, sends back a photo of the planet’s surface.
On May 15, China’s Tianwen 1 probe made a histone landing on Mars! People all over the world applauded the successful landing, as it was very hard to pull off(成功).
In July 2020, Tianwen 1 was launched from the Wenchang Space Launch Center. In February, the probe entered Mars’ orbit. Experts said the difficulty of sending the probe into orbit was equal to hitting a golf ball from Paris and landing it in a hole in Tokyo. But it still couldn’t match the difficulty of the final landing stage, which is also called the “nine minutes of terror(恐怖)”. How did Tianwen 1 do it? Let’s take a look.
Nine minutes of terror
Within nine minutes, the probe had to slow its speed from 20,000 km per hour to zero, landing from 125 km above Mars. Since the probe is 320 million km away from Earth, there is a signal delay(延迟) of over 10 minutes if the research team tries to control it from Earth. So the probe had to carry out the landing by itself!
The drag(空气阻力) created by the atmosphere slowed it down first. During this process, the surface of the craft heated up to 2,100°C, which could melt the craft! Fortunately, it had a heat shield(抗热涂层) to protect it.
Next, a parachute(降落伞) opened to further reduce the craft’s speed. This was also a dangerous process, as the parachute’s ropes could break due to(由于) the craft’s high speed. Researchers used special materials to make the ropes strong enough to stay in one piece.
At 1.5 km above Mars, the craft fired its retrorockets(反向火箭) as another way to help it slowdown. At 100 meters, the craft stayed in the air and used its sensors (传感器) to check the landing area. It had to move away from obstacles(障碍物) such as rocks before finally touching down.
Following the US, China is now the second country in the world to successfully land a probe(探测器) on Mars. It will give Chinese scientists their first opportunity to closely study the Red Planet. Tianwen 1 makes it to Mars.
21. When did the probe enter Mars’ orbit?
A.In July 2020. | B.In February 2021. | C.On May 15, 2021. | D.In July 2021. |
22. How far away was the probe from Earth while landing on Mars?
A.1.5 km. | B.125 km. | C.20,000 km. | D.320 million km. |
23. Why does the craft have a heat shield?
A.To reduce drag. | B.To heat up the atmosphere. |
C.To make the landing process faster. | D.To protect it from melting. |
24. What worked to slow down the probe just before its touchdown?
A.The drag created by the atmosphere. | B.Ropes made of special materials. |
C.A parachute. | D.Retrorockets. |
25. What is the focus of the passage?
A.Why Tianwen 1’s landing was out of control. | B.How Tianwen 1 landed on Mars successfully. |
C.Tianwen 1’s journey to Mars. | D.The launch of Tianwen 1. |