[4] The two craft flew over the equator and south polar regions, analyzing the atmosphere and the surface with remote sensors, and recording and relaying hundreds of pictures.

The spacecraft were shipped to Cape Canaveral with their Atlas-Centaur boosters in December 1968 – January 1969 to begin pre-launch checkouts and testing.

During the test run, an electrical relay in the Atlas malfunctioned and opened two valves in the pneumatic system which allowed helium pressure gas to escape from the booster's balloon skin.

The Atlas began to crumple over, however two pad technicians quickly activated a manual override switch to close the valves and pump helium back in.

NASA awarded the quick-thinking technicians, Bill McClure and Charles (Jack) Beverlin, Exceptional Bravery Medals for their courage in risking being crushed underneath the 124-foot (38 m) rocket.

In 2014, an escarpment on Mars which NASA'S Opportunity rover had recently visited was named the McClure-Beverlin Ridge in honor of the pair, who had since died.

In addition, BECO occurred a few seconds early due to a faulty cutoff switch, resulting in longer than intended burn time of the sustainer engine, but this had no serious effect on vehicle performance or the flight path.

This served two purposes, firstly to prevent venting propellant from the spent Centaur from contacting the probe, secondly to put the vehicle on a trajectory that would send it into solar orbit and not impact the Martian surface, potentially contaminating the planet with Earth microbes.

[9] By chance, both spacecraft flew over cratered regions and missed both the giant northern volcanoes and the equatorial grand canyon discovered later.

Coming a week after Apollo 11, Mariner 6 and 7's flyby of Mars received less than the normal amount of media coverage for a mission of this significance.

It utilized 3 gyros, 2 sets of 6 nitrogen jets, which were mounted on the ends of the solar panels, a Canopus tracker, and two primary and four secondary Sun sensors.

Communications were accomplished through the high- and low-gain antennas, via dual S-band traveling wave tube amplifiers, operating at 10 or 20 watts, for transmission.

The command system, consisting of a central computer and sequencer (CC&S), was designed to actuate specific events at precise times.