Mariner 4
Mariner 4 was the fourth in a series of spacecraft
Mariner program
The Mariner program was a program conducted by the American space agency NASA that launched a series of robotic interplanetary probes designed to investigate Mars, Venus and Mercury from 1963 to 1973...

, launched on November 28, 1964, intended for planetary exploration in a flyby mode and performed the first successful flyby of the planet Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

, returning the first pictures of the Martian surface. It captured the first images of another planet ever returned from deep space
Outer space
Outer space is the void that exists between celestial bodies, including the Earth. It is not completely empty, but consists of a hard vacuum containing a low density of particles: predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, and neutrinos....

; their depiction of a cratered, seemingly dead world largely changed the view of the scientific community on life on Mars
Life on Mars
Scientists have long speculated about the possibility of life on Mars owing to the planet's proximity and similarity to Earth. Fictional Martians have been a recurring feature of popular entertainment of the 20th and 21st centuries, but it remains an open question whether life currently exists on...

. Mariner 4 was designed to conduct closeup scientific observations of Mars and to transmit these observations to Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...