united states. they look at how they mitigate this, whether or not they retaliate. the idea is to see whether or not we're ready if something like that occurs. >> jeanne, thank you. >> reporter: you bet. top stories for you now. first-time claims for jobless benefits slipped sharply last week. the labor department counts 440,000. the number of continuing unemployment claims also took a noticeable dip. south africans celebrating nelson mandela, 20 years ago today he walked out of prison setting off events that ended white minority rule in south africa and his election as president. mandela, a frail 91 now, has largely retired from public life. "endeavour" astronauts step out to hook up a new module on the space station. they will also install a bay window on the space station to give the crew a panoramic view of earth. airports are ready for business, but some airlines aren't flying today.