Instruments: Television Camera, Solar Plasma probe,
Ionization chamber, Trapped radiation detector,, Helium vector magnetometer,
Cosmia ray telescope, Cosmic dust detector
Project Manager: Jack N. James Project Scientist:
Richard K. Sloan
Mariner 4 gave scientists their first glimpse of
Mars at close range, passing over the planet at an altitude of 9,846
kilometers (6,118 miles) above the surface and putting to rest the
myths of the late 19th century that the planet may have harbored
an advanced civilization. Launched on November 28, 1964, Mariner
4 carried a television camera and six other science instruments
to study interplanetary space between the orbits of Earth and Mars
and in the vicinity of Mars itself. The spacecraft took 22 television
pictures covering about 1 percent of Mars's surface, which revealed
a vast, barren wasteland of craters strewn about a rust-colored
carpet of sand. The canals that Percival Lowell had spied with his
telescope in 1890 proved to be an optical illusion, but natural
waterways of some kind seemed to be evident in some regions of the
planet. Other experiments measured atmospheric density and the interplanetary
medium.
Once past Mars, Mariner 4 journeyed on to the far
side of the Sun before returning to the vicinity of Earth again
in 1967. Nearly out of power by then, engineers decided to use the
aging craft for a series of operational and telemetry tests to improve
their knowledge of the technologies that would be needed for future
interplanetary spacecraft. All operations of the spacecraft ceased
on December 20, 1967.
