Astronaut Alan Bean.
Alan LaVern Bean (born March 15, 1932) is a former NASA Astronaut and became the fourth man to walk on the moon at the age of 37.
Captain Bean was the lunar module pilot on Apollo 12, the second lunar landing. In November 1969, Captain Bean and Captain Pete Conrad landed in the moon's Ocean of Storms.
Hope that helps.
The fourth astronaut would be Alan Bean,who landed on the moon during the 5th and 6th of November 1969, aboard the Apollo 12.