thomas reiter spent many months doing experiments in orbit.is back down on earth as director of human space flight operations at the european space agency. we asked him what kind of projects he was working on in his career as an astronaut. >> maybe i can give you two examples in the area of human research. osteoporosis is a widely distributed disease, and still, it is not very well understood what the real cause of this disease is. of course, today we're able to fight the symptoms, but we're not yet able to really find the root of this disease. working in microgravity can help to understand the mechanisms that initiate this disease and help to protect people on earth who are suffering from osteoporosis. maybe another example from the area of biochemistry, it is possible in weightlessness to generate protein crystals. proteins play a very important role in all life functions, in all bodies. crystallizing those proteins and analyzing them gives us insight in how these proteins are actually working, how their functioning, and that is indeed a pre

thomas. >> i am sarah kelly. here is what is coming up. pressure grows on bashar al- assad as western powers to expel syrian diplomats. >> on his first state visit to israel, germany's new president reiterateserlin's commitment to the nation's security. >> powerful aftershocks in northern italy. at least 15 people are dead. ♪ >> syria is added to pinpoint -- those are the words of international envoy kofi annan and sit-ins' to salvage his tattered peace plan for the country. >> western powers have accused the syrian government of being behind last week's houla massacre that cost over 100 lives. in response, at least 10 nations, including the u.s. and germany, have been making moves to kick out syrian diplomats. >> syrian president bashar al- assad has denied any responsibility for the houla massacre, saying islamist extremists were to blame, as the pressure mounts. >> syria's ambassador left the french foreign ministry after getting the boot. he had just been informed that he had 72 hours to leave france. >> this was not decided by france unilaterally. it was in concert. >> in concert with other nations around the world, including britain, germany, and many other european countries, as well