Mariner 4 - Mission to Mars

Overview:
Mariner 4 was the 1st spacecraft to get a close look at Mars. Flying as close as 9,846 km, Mariner 4 revealed Mars to have a cratered, rust-colored surface, with signs on some parts of the planet that liquid water had once etched its way into the soil.

In addition to various field and particle sensors and detectors, the Mariner 4 spacecraft had a television camera, which took 22 television pictures covering about 1% of the planet. Initially stored on a 4-track tape recorder, these pictures took four days to transmit to Earth.

Once past Mars, Mariner 4 orbited the Sun prior to returning to the vicinity of Earth in 1967. Engineers then 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.

Objectives:
The Mariner 4 mission to Mars was designed to meet three major objectives:

• Study interplanetary fields and particles, including the magnetic field of Mars, cosmic dust, cosmic rays, and the solar wind.
• Take close-up images of Mars in hopes of discovering the geologic and atmospheric processes at work on the planet over the eons.
• Provide experience in operating long-term interplanetary missions.

After Mariner 4 was well under way to Mars, an experiment was approved to study the effect of transmitting the spacecraft's radio signal through the Martian atmosphere just before the spacecraft disappeared behind the planet. This experiment would reveal much about the atmosphere of Mars. In order to perform this experiment, the spacecraft's computer had to be reprogrammed from Earth. This engineering feat, pioneered on Mariner 4, has been greatly refined and repeated numerous times in later missions, both to enhance and to salvage.

Key Dates

• 11.28.64: Launch (14:22:01 UT)
• 07.15.65: Mars Flyby (01:00:57 UT)
• Status: Mission Complete