sentences:  The go-ahead was given and on 31 January 1958, America's first satellite, "Explorer I", was placed into orbit using a modified Jupiter launch vehicle (a four-stage system designated Juno I).The Army Ordnance Missile Command (AOMC) was formed in March 1958.Headquartered at Redstone Arsenal and commanded by Maj. Gen. Medaris, AOMC had several subordinate elements, including ABMA, White Sands Missile Range, and the Jet Propulsion Laboratory at California Institute of Technology.