Video: Post-launch news conference

Without any public warning, a Chinese Long March 4B rocket lifted off Sunday with two “environmental monitoring satellites” that the country’s state media said will replace a pair of spacecraft launched in 2008 that collected data to assist in a series of disaster relief efforts over the last decade.

A series of unprecedented back-to-back test-firings of a rocket engine originally developed for NASA’s space shuttle concluded earlier this month, giving engineers data crucial to achieving rapid 24-hour turnarounds planned for a U.S. military-funded reusable winged booster under construction at Boeing, government and industry officials said.

Riding a half-million pounds of thrust, a Minotaur 4 rocket fired off a launch pad in Virginia, surpassed the speed of sound in less than 20 seconds, and vaulted into orbit Wednesday with four classified payloads for the National Reconnaissance Office.