It was 35 years ago on this day. The Pioneer Venus Orbiter was launched atop an Atlas-Centaur rocket. The launch kicked off the Pioneer project and was one of two components, the second of which launched in August of 1978.
After the May 20, 1978 launch the orbiter arrived at Venus and was placed into orbit on December 4, 1978. The oribiter was 2.5 meters (8.2 feet) across by 1.2 meters (3.49 feet) high and was packed with 17 experiments.
One of the products was the first topographical map of Venus shown at the top of the post.
The Pioneer Venus Orbiter provided data until 1992 when it entered and was destroyed by the atmosphere of Venus. It is worth mentioning that for the first ten years of operation and that includes building the spacecraft, the cost was 125 million dollars.