Mariner 4 was a NASA spacecraft. It was the fourth spacecraft in the Mariner program. It was sent on a Mars flyby mission. It was the first successful mission to Mars. The spacecraft was launched on November 28, 1964 at Cape Canaveral Air Force Station. Mariner 4 reached Mars after an eight-month journey. The spacecraft became the first spacecraft to take close-up photographs of another planet. The spacecraft also had other instruments to study the atmosphere of Mars.