Beijing — Beijing Tianbing Technology Company said Sunday that the first stage of its Tianlong-3 rocket under development had detached from its launch pad during a test due to structural failure and landed in a hilly area of the city of Gongyi in central China. There were no reports of casualties after an initial investigation, Beijing Tianbing, also known as Space Pioneer, said in a statement on its official WeChat account. Parts of the rocket stage were scattered within a “safe area” but caused a local fire, according to a separate statement by the Gongyi emergency management bureau. The fire has since been extinguished and no one has been hurt, the bureau said. The two-stage Tianlong-3 (“Sky Dragon 3”) is a partly reusable rocket under development by Space Pioneer, one of a small group of private-sector rocket makers that have grown rapidly over the past five years. Falling rocket debris in …