On which NASA spacecraft were the Pioneer plaques placed?

On which NASA spacecraft were the Pioneer plaques placed? The answer is Pioneer 10 and 11.

The Pioneer plaques were gold-anodized aluminum plates attached to NASA's Pioneer 10 and Pioneer 11 spacecraft. They carried a pictorial message intended to communicate basic information about humanity and Earth's location to any intelligent beings that might eventually encounter the probes.

Carl Sagan and Frank Drake designed the plaque, with artwork by Linda Salzman Sagan. Its symbols included a diagram of the hydrogen atom, a map based on pulsars, a depiction of the Solar System, and human figures. The hydrogen transition supplied common units of time and distance, while the pulsar map indicated the Sun's position in the galaxy.

Pioneer 10 launched on March 2, 1972, and Pioneer 11 followed on April 5, 1973. The plaques are often confused with the Voyager Golden Record, but the plaques traveled on the Pioneer probes; the record was carried by Voyager 1 and Voyager 2.