万花筒2008-02-21:美国欲导弹打卫星（在线收听）

The Pentagon plans to shoot down a disabled spy satellite to prevent a potential deadly gas leak, officials said.

Upon notification of the descending NRO satellite, the President and his national and homeland security advisors reviewed the options available to us, to mitigate risk from the descending satellite.

As background, I'd like to note that over the past 30-plus years, uh, there have been many satellites and other man-made objects falling from space of course, uh, they’ve fallen uh, with very little damage and no injuries. Uh, what makes this case a little bit different however, and in particular for the President in his consideration, uh, was the likelihood that the satellite upon descent to the Earth’s surface, could release much of its thousand-plus pounds of hydrazine fuel as a toxic gas. 

The likelihood of the satellite falling in a populated area is small, and the extent and duration of toxic hydrazine in the atmosphere would be quite limited, nevertheless, if the satellite did fall in a populated area, there was a possibility of death or injury to human beings, beyond that associated with the fall of satellites and other space uh, objects normally, if we can use that word, specifically, there was enough of a risk for the President to be quite concerned about human life, and on that basis, he asked us to review our options. 

WORDS IN THE NEWS     

1. NRO : National Reconnaissance Office

The National Reconnaissance Office (NRO) helps the US practice the first rule of warfare: Know thine enemy. Called the "nation's eyes and ears in space," the Department of Defense agency designs, builds, and operates US reconnaissance satellites for the Central Intelligence Agency and the DoD. 

2. mitigate : verb

To mitigate something means to make it less unpleasant, serious, or painful. (FORMAL)