A Long March 2-D rocket carrying the Dark Matter Particle Explorer Satellite blasts off at the Jiuquan Satellite Launch Center in Jiuquan, northwest China's Gansu Province, Dec. 17, 2015. The satellite, nicknamed "Wukong" after the Monkey King with penetrating eyes in the Chinese classical fiction "Pilgrimage to the West", is the country's first space telescope in a fresh search for smoking-gun signals of dark matter, invisible material that scientists say makes up most of the universe's mass.