SSS 2011-11-18(在线收听

 On November 8th, Russia launched a probe toward the tiny Martian moon Phobos. The launch was picture-perfect, and the spacecraft, called Phobos–Grunt, soared into the night sky over Kazakhstan.

 
The good news stops there.
 
For instead of boosting itself onto a Mars-bound trajectory, Phobos–Grunt has for some reason remained in Earth orbit. Ground controllers are trying to contact the probe in the hopes that they can coax it to fire up its engines. But time is running out.
 
Details on the mission mishap are scarce, but the head of the Russian space agency has told reporters that Phobos–Grunt has until December to push off for Mars. After that, the planets will be out of alignment and a Mars trajectory will be out of the question.
 
If mission controllers can't establish contact, Phobos–Grunt's orbit will gradually decay. And soon it will become just the latest spacecraft to fall back to Earth. It's a big one, too, weighing in at about 13 metric tons. So there's a possibility some debris could reach Earth's surface. All the more reason to hope Phobos–Grunt snaps out of it. And soon.
 
Thanks for the minute. For Scientific American's 60-Second Science, I'm John Matson.
  原文地址:http://www.tingroom.com/lesson/sasss/2011/11/163937.html