Mariner Missions to Venus and Mars
Mariner 8 Information
Mariner-H, also commonly known as Mariner 8, was (along with Mariner 9) part of the Mariner Mars 71 project. It was intended to go into Mars orbit and return images and data. The overall goals of the series were to search for an environment that could support life; to collect data on the origin and evolution of the planet; to gather information on planetary physics, geology, planetology, and cosmology; and to provide data that could aid future spacecraft such as the Viking Landers.
Mariner 3 Information
In November of 1962, NASA authorized and began planning for two probes for the Mariner-Mars 1964 project. The mission was to photograph the Martian surface using a single TV camera that would be attached to a scan platform, returning up to 21 photographs during the eight month journey. The first of the two probes, Mariner 3, launched in November of 1964, but the booster payload shroud failed to separate from the payload.
Mariner 9 Information
Mariner 9 was heavier than Mariners 6 & 7 combined & it needed it. Although its instrument payload was similar to those earlier spacecraft, it needed a larger propulsion system for control in Mars orbit. Mariner 9 was the first spacecraft to orbit another planet. Upon arrival at Mars, Mariner 9 discovered that the atmosphere was so dusty that the surface was obscured. This proved the case for studying a planet from orbit rather than just on a flyby mission.
Mariner 6 and 7 Missions Information
Mariners 6 and 7 were paired together, identical teammates in a two-spacecraft mission to Mars. The two spacecraft were launched 31 days apart using Atlas/Centaur rockets and they arrived at their closest approach to Mars (3,430 kilometers, or 2,130 miles) just four days apart. Between the two spacecraft, they transmitted to Earth a total of 143 pictures of Mars as they approached the planet and 55 close-up pictures as they flew past the equator and southern hemisphere.
Mariner 2 Mission Information - Mariner 2 Venus Flyby
The rocket carrying Mariner 1 went off-course during launch on July 22, 1962, and was blown up by a range safety officer about 5 minutes into flight. NASA wasted no time in implementing a backup plan and within 36 hours of the failure of Mariner 1 had the Mariner R-2 spacecraft out of storage and launched. Mariner 2, as it was known after launch, was equipped with an identical complement of instrumentation to that of its predecessor. Unlike Mariner 1, Mariner 2 was a success.
Mariner 4 was the first spacecraft to get a close look at Mars. Flying as close as 9,846 kilometers (6,118 miles), 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.
Mariner 5 - Mission to Venus
Mariner 5 was originally built as backup for Mariner 4 to Mars, but was never needed. It was refurbished & modified to go to Venus instead. Flew by Venus at a distance of 3,990 km (2,480 miles), & with its more sensitive instruments than Mariner 2, revealed new information about Venus' atmosphere, including its composition of 85-99% carbon dioxide.