Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: (CNN) Eugene A. Cernan, the last astronaut to leave his footprints on the surface of the moon, has died, NASA said Monday. The retired United States Navy captain was 82. His family confirmed the news in a statement Monday, saying he died following "ongoing health issues." "Our family is heartbroken, of course, and we truly appreciate everyone's thoughts and prayers. Gene, as he was known by so many, was a loving husband, father, grandfather, brother and friend," the family said. Cernan's death comes a little more than a month after fellow astronaut John Glenn died in December. Cernan earned several distinctions in his 13 years with NASA. He was the second American to walk in space and one of three men to have flown twice to the moon.Cernan was commander of Apollo 17, last mission to the moon in December 1972He was one of three men to fly to the moon twice 
 Question:His family said his experience as an _ astronaut had humbled him.

Apollo 17