Northrop Grumman’s Antares rocket will deliver a Cygnus supply ship into orbit Saturday to begin a pursuit of the International Space Station.

An Orbital ATK Minotaur 4 rocket partially powered by modified motors from a Cold War-era nuclear missile lifted off early Saturday from Cape Canaveral with a small U.S. military satellite to help track other objects in space. The solid-fueled launcher took off at 2:04 a.m. EDT (0604 GMT) after a weather delay.

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.