In the two weeks since Curiosity rover landed on Mars, NASA engineers have been ecstatic over what has been sent to earth.
This, however, isn't the first landing on Mars that produced beyond belief results. On this day in 1975, Viking One launched from Cape Canaveral on a mission to Mars.
It put down its Viking One lander onto the surface of the planet July 20, 1976.
Also, on this day in 1977, the U.S. launched Voyager Two.
The unmanned spacecraft carried a 12-inch copper phonograph record that contained greetings in dozens of languages, samples of music and sounds of nature.
Voyager Two still is going 35 years later! It has passed Jupiter, Saturn, Uranus and Neptune. It is still the only spacecraft to have visited those outer planets.