English: CAPE CANAVERAL, Fla. – Engine ignition lifts the United Launch Alliance Atlas V rocket carrying NASA's Solar Dynamics Observatory off Launch Complex 41 on Cape Canaveral Air Force Station. Liftoff was at 10:23 a.m. EST Feb. 11. This is the 100th launch of a commercial Atlas/Centaur rocket. The observatory, known as SDO, is the first mission in NASA's Living With a Star Program and is designed to study the causes of solar variability and its impacts on Earth. The spacecraft's long-term measurements will give solar scientists in-depth information to help characterize the interior of the Sun, the Sun's magnetic field, the hot plasma of the solar corona, and the density of radiation that creates the ionosphere of the planets. The information will be used to create better forecasts of space weather needed to protect the aircraft, satellites and astronauts living and working in space. For information on SDO, visit http://www.nasa.gov/sdo.