The mariner series of missions were designed to be the first U.S. Spacecraft To other planets mostly Venus and Mars.
Dates of discoveries
Mariner 2 got launched In 1962 the first successful probe flew by, it returned information which confirmed that Venus is very hot. Mariner 3 got launched on November 5, 1964 ,was lost when it's protective shroud failed to eject as the craft was placed into interplanetary space. Unable to collect the suns energy for power from its solar panels, the probe soon died when its battery's ran out and it is now in solar orbit
Technology they used
There were about 10 or 9 satellites sent into space.the United States spacecraft mariner series explored the inner solar system, gaining information about mercury , Venus and Mars.the first successful space probe and first spacecraft to visit a planet was mariner 2 in 1962.
What contribution they made to our knowledge and understanding the solar system
The mariner missions have contributed to our knowledge of the solar system in many ways, such as many photographic images of planets which reveals the types of surfaces and atmosphere on planets.which helps us learn about the solar system