Here's something Missouri S&T's Greg Hilmas, who is working on materials that could protect hypersonic missiles from intense heat, told us a year or two ago:

“These hypersonic vehicles are just test vehicles right now or simply on the drawing board. It is expected that they will exit and re-enter the atmosphere as they are gliding toward their intended target.”

WASHINGTON (AP) - U.S. officials say the Pentagon is planning to shoot down a broken spy satellite expected to hit the Earth in early March.

The Associated Press has learned that the option preferred by the Bush administration will be to fire a missile from a U.S. Navy cruiser, and shoot down the satellite before it enters Earth's atmosphere.

The officials spoke on condition of anonymity because the options will not be publicly discussed until a Pentagon briefing later Thursday.