Space junks threaten future mission

 　　BEIJING, Sept. 6 (Xinhuanet) -- The amount of space junks floating in Earth's orbit has reached a critical level, warned scientists.

　　The future space missions may become too dangerous to fly for a risk of colliding with space junks, said a report released recently by the U.S. National Research Council (NRC).

　　The kinds of space junks range from huge, the report said, there are thousands of discarded satellites and rocket boosters and countless¹ tiny pieces of daily gabages from space missions.

　　The debris² are traveling in orbit at 17,500mph, at such a speed even a tiny clash can destroy a spacecraft.

　　The NRC recommended that NASA should launch a plan to clean up the floating debris and called on other major space nations' cooperation.

　　"The current space environment is growing increasingly hazardous³ to spacecraft and astronauts," said Kessler, an ex-NASA researcher, "NASA needs to determine the best path forward for tackling the multifaceted problems caused by meteoroids and orbital debris that put human and robotic space operations at risk."

1 countless   

adj.无数的，多得不计其数的

参考例句：

• In the war countless innocent people lost their lives.在这场战争中无数无辜的人丧失了性命。
• I've told you countless times.我已经告诉你无数遍了。

2 debris   

n.瓦砾堆，废墟，碎片

参考例句：

• After the bombing there was a lot of debris everywhere.轰炸之后到处瓦砾成堆。
• Bacteria sticks to food debris in the teeth,causing decay.细菌附着在牙缝中的食物残渣上，导致蛀牙。

3 hazardous   

adj.(有)危险的，冒险的；碰运气的

参考例句：

• These conditions are very hazardous for shipping.这些情况对航海非常不利。
• Everybody said that it was a hazardous investment.大家都说那是一次危险的投资。