Pioneer 10

Pioneer 10 launched on March 2, 1972, and became the first spacecraft to traverse the asteroid belt — then feared to be a lethal barrier — and the first to reach Jupiter, flying past the giant planet in December 1973. Its instruments returned the first close-up images of Jupiter and direct measurements of its punishing radiation belts, data that shaped the design of every outer-planet mission since.

Powered by radioisotope generators rather than solar panels, Pioneer 10 kept transmitting for more than 30 years as it coasted toward the edge of the solar system, its final faint signal received in 2003. The spacecraft carries the famous Pioneer plaque — a gold-anodized greeting card from humanity, designed by Carl Sagan and Frank Drake, for any civilization that might one day find it.