One way to eliminate the guesswork would be to spot asteroids on the way in and then go pick them up for analysis. This is where the NEO Program and its orbit-projection expert, Steven Chesley, come in. Chesley, whose thick beard makes him look more like a grizzled sailor than an astro-geek, has helped develop, and is constantly updating, a software program called Sentry that searches for possible asteroid impacts and their probabilities up to a century into the future. On the morning after astronomers spotted TC3, 13 hours before the asteroid would hit Earth, Chesley was getting his kids ready for school when he got a call from Tim Spahr of the Smithsonian Astrophysical Observatory's Minor Planet Center. The MPC is tasked with gathering and collating telescope data on asteroid sightings. When Spahr sifted through the data that morning, he saw that the computer couldn't make sense of certain telescope observations—one object in particular was too close, moving too fast. He ran it through MPC's orbit-projection software, which can tell how close an asteroid will come to Earth, and phoned Chesley to alert him of an impending collision. Chesley nearly fell out of his chair when he heard the news. He hurried to work and began crunching data, eventually processing information from 26 different observatories, totaling 570 positional measurements of the asteroid.