the challenger accident is an important part our history, a tragic reminder that space exploration is risky and never be trivialized. nasa works everyday to honor the legacy of our fallen astronauts as we carry out our mission to reach for new heights and reach the university. >> i saw "gravity" over the weekend. so you know what goes on up there. the song, according to beyonce, said was recorded with sincerest intention to help heal those who lost loved ones and to remind us that the unexpected things happen, so love and appreciate every minute you have. >> yeah. okay. so that's what she said. has there been a burning need for families to cope with something that happened two decades ago? it sounds like creative spin on her part. but still, you wonder what were they thinking to use an actuality from the moment seven people lost their lives? >> do you think she knew this would cause this furor, that we'd be talking about this? >> i would hope not. >> certainly i think if she thought she would lose money or that she would upset anybody, i would think she would never step