Europe Ready To Land 1st Probe On Streaking Comet

Some anxious moments today for controllers at the European Space Agency.

They've been working for more than a decade, preparing to land a spacecraft on a comet. And they'll find out tomorrow whether their plan is a success.  

But today, the space agency announced that the systems aboard the lander had failed to switch on properly at first. They tried a reboot -- and it worked. The agency says the lander ``successfully powered up.''  

Tomorrow, controllers will give the Rosetta space probe the final go-ahead to drop the lander onto the comet. Rosetta will execute a series of maneuvers to reach the best drop-off point, and then the lander will separate from the mother ship.  

If anything goes wrong then, scientists won't be able to do anything but watch. Since it takes 28 minutes for a command to get that far, the lander has been programmed to perform the touchdown on its own.  

Even the smallest error could put the lander hundreds of yards off course during its seven-hour descent to the comet. It's supposed to land on a site that was chosen because it is fairly free of boulders.  

Even if the landing fails, the mission manager says Rosetta alone will be able to gather much of the data that scientists hope will help them learn more about the origins of comets, stars, planets and even life on Earth.