NASA Pioneer Mission - Video

On April 5, 1973, exactly 40 years ago today, Pioneer 11 blasted off from Cape Canaveral for a risky mission that would take the small satellite dangerously close to Jupiter's surface and through Saturn's outer rings, paving the way even more ambitious explorations of the solar system.

The spacecraft had a tough act to follow. Its sister craft, Pioneer 10, which launched on March 2, 1972, was the first to fly beyond Mars, the first to fly through the asteroid belt and the first to zip by Jupiter, sending volumes of scientific data back to Earth.

But Pioneer 10's success allowed NASA managers to set their sights higher for the 9.5-foot (2.8-m), 570-pound (258-kg) Pioneer 11. The spacecraft would fly not only three times closer to Jupiter than Pioneer 10 but it would also whiz past the next planet out: Saturn.