Lately, there has been much ado in the media about satellite US-193. This satellite is a National Reconnaissance Office satellite. In other words, it's a spy satellite, on a classified mission. There's not much one can hide from amateur astronomers, however, as the satellite can often be seen in the afternoon. Click here for information on when you can see it. It has been known for some time now that it had lost power and communications and would be re-entering the atmosphere at some point. Now, the government is concerned about this re-entry and is actually planning to blow the satellite out of the sky, before it reaches the surface.
US-193 weighs about 5,000 pounds. While a good portion of this mass would burn up in the atmosphere, about 2,500 pounds could impact the surface. This could cause major damage in a populated area. Another concern is that the satellite's hydrazine fuel, a hazardous substance could be dissipated upon impact. This would mean nearly 1,000 pounds of toxic fumes being thrown into a possibly populated area. If the US were to destroy the satellite in space, it could disperse the hydrazine harmlessly. The trouble is, there's only a short window in which it could be effectively destroyed. If the missile were fired too late, it would not only defeat the purpose, but would be extremely difficult. This is because as the satellite re-enters the atmosphere, its motion will become mostly erratic.
Current position of US-193, courtesy of Heavens-Above.com
Another reason that the government wants to shoot down this satellite is its very purpose itself. The satellite is a spy satellite, so the US government would not like it to fall into the wrong hands, if any parts survived. This exercise is also a good excuse to test out new "Star Wars" style weapons defense systems. Last year, China destroyed one of its own satellites using a ground based missile. This could be an attempt to show, "We can do that too." What better excuse to destroy a satellite? Could this be the next Cold War in space? Most likely not. We'll probably see the conspiracy theorists come out of the woodwork on this one.
Hopefully, this satellite will be destroyed when on the night side of the Earth, visible to amateur astronomers. If details come up about the time and location of its destruction, I'll keep you posted.