Several days after space shuttle Discovery arrives at the international space station, some of the lights will go out. Some communications with Mission Control will stop. Backup power will be lost. That may sound scary for the astronauts orbiting 220 miles above Earth, but they'll be ready for it. The space lab is only getting rewired. Parts of the US section of the space station will be powered down during Discovery's visit this month as spacewalking astronauts reconnect the lab's electrical system from a temporary to a permanent power source. "It's kind of like leaving the power on in your house and rewiring the east wing without turning off the main breaker