The Poker Flat Research Range (PFRR) is a launch facility and rocket range for sounding rockets in the U.S. state of Alaska. The world's largest land-based rocket range, it is on a site about 30 miles (50 km) northeast of Fairbanks and 1.5 degrees south of the Arctic Circle. More than 1,700 launches have been conducted at the range to study the Earth's atmosphere and the interaction between the atmosphere and the space environment. Areas studied at PFRR include the aurora, plasma physics, the ozone layer, solar proton events, Earth's magnetic field, and ultraviolet radiation. Rockets launched at PFRR have attained an apogee of .