Defunct U.S. satellite crash avoidable: Chinese expert
英语课
BEIJING, Sept. 23 (Xinhua) -- A defunct 1 U.S. satellite is expected to crash down to Earth Friday, with nobody knowing where or when exactly it will hit. This was avoidable, a Chinese expert said Thursday.
Pang 2 Zhihao, a researcher from the Chinese Research Institute of Space Technology, told Xinhua that the crash could have been avoided had the satellite been put into a higher orbit, or manipulated to drop in the South Pacific when it had abundant fuel. It would pose no threat to Earth if these measures had been taken.
NASA's tumbling, 5,900 kg Upper Atmosphere Research Satellite, or UARS, is the first of such man-made space vehicles that have been launched into outer space according to the agency's Mission to Planet Earth. The mission was launched in the 1990s.
The mission is designed to provide data for better understanding Earth's upper atmosphere and the effects of natural and human interactions on the atmosphere.
The satellite was deactivated 3 in 2005 as it ran out of fuel and was left orbiting Earth like a big piece of space junk.
There are other cases of defunct satellites. The European Space Agency said earlier its observation satellite ERS-2 has run out of fuel and is deorbiting. It would therefore also crash sooner or later.
Pang said all countries which are operating space vehicles should take care of their own spacecrafts so that they won't pose any danger.
The expert also said that the public need not worry too much.
Pang said most spacecrafts will be incinerated upon re-entering Earth's atmosphere, and the debris 4 will mostly likely fall into the ocean or hit an uninhabited area. In addition, a debris tracker is able to give a comparatively accurate prediction where the craft will fall about two hours before it hits Earth, giving residents, if there are any, time to evacuate 5.
He added that there are several ways to minimize the threat of decommissioned spacecrafts, like putting them into higher orbits and crashing them into designated waters.
Scientific progress would possibly bring about more ways of dealing 6 with tumbling satellites. Scientists have already been trying to build spacecrafts with degradable materials so that they can self-destruct when re-entering Earth's atmosphere.
adj.死亡的；已倒闭的
- The scheme for building an airport seems to be completely defunct now.建造新机场的计划看来整个完蛋了。
- This schema object is defunct.No modifications are allowed until it is made active again.此架构对象不起作用。在重新激活之前，不能进行任何改动。
n.剧痛，悲痛，苦闷
- She experienced a sharp pang of disappointment.她经历了失望的巨大痛苦。
- She was beginning to know the pang of disappointed love.她开始尝到了失恋的痛苦。
v.解除动员( deactivate的过去式和过去分词 )；使无效；复员；使不活动
- \"The brain can be deactivated. It can be yours to command.\" “大脑计算机可以被停止。如果你下达命令的话。” 来自互联网
- He successfully deactivated a nuclear reactor in a laboratory before meltdown. 他成功停用一个核反应堆在实验室之前崩溃。 来自互联网
n.瓦砾堆，废墟，碎片
- 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。
v.遣送；搬空；抽出；排泄；大(小)便
- We must evacuate those soldiers at once!我们必须立即撤出这些士兵！
- They were planning to evacuate the seventy American officials still in the country.他们正计划转移仍滞留在该国的70名美国官员。