According to NASA's Near Earth Objects (NEO) program, there are more than 1,300 Potentially Hazardous Asteroids(PHAs) with at least a very small chance of impacting us someday. Anything over 150 yards across that appears to be on a potential collision course with Earth at some time in the future is very worrisome. But the main difficulty in making predictions is in obtaining sufficient observations to determine the orbits of the PHAs. Scheduled for launch in 2016, NASA's OSIRIS-REx mission will make precise measurements of one potentially dangerous PHA called 1999 RQ36. OSIRIS-REx will arrive at RQ36 in 2018 and orbit the asteroid until 2021, all the while getting a much better view of subtle changes in the asteroid's orbit. As an added bonus, the spacecraft will collect a sample and return it to Earth.