the usa responded by launching the vanguard rocket, that was intended to be the first launch vehicle the united states would use to place a satellite into orbit. instead, the sputnik crisis caused by the surprise launch of sputnik 1 led the u.s., after the failure of vanguard tv-3, to quickly orbit the explorer 1 satellite using a juno i rocket launched on 1 february 1958. thus vanguard 1 was the second successful u.s. orbital launch. thus started the space race, that gave the drive to put men on the moon with the usa's apollo program.