Mourning space pioneer Eugene Cernan

When astronaut Eugene Cernan left the surface of the moon after a very active Apollo 17 lunar expedition in 1972, he knew he was the last man on the moon, at least for a while.

He didn’t suspect he’d be the last man on the moon for the rest of his life.

Cernan, who died Monday at age 82, didn’t have the all-American persona of John Glenn, the first American to orbit the Earth, nor the luck of being first, such as Alan Shepherd as the first American in space or Neil Armstrong as the first man to walk on the moon.

But he was important to the space program as a true professional with a scientific heart and a pilot’s personality. His flights aboard an earlier Gemini mission and the lunar orbit of Apollo 10 were crucial to the six successful lunar landings, improving spaceflight all along the way.

He often teased that his Apollo 10 flight “painted the white line” for Armstrong to follow to the Sea of Tranquility in July 1969.

But in addition to the fun of being on the moon— it was an adventure for the dozen men who walked its surface —Cernan commanded the most advanced of the lunar missions...