In 1967, Newell was promoted to the position of associate administrator of NASA, the third-ranking position in the agency, which he held until his retirement in 1974. He held this post under four successive NASA administrators. Among other activities in this position, he traveled to the Rice Hotel in Houston to meet with disgruntled scientist-astronauts in 1971. Among the results of that meeting was the assignment of Dr. Harrison Schmitt as the last human being (and only scientist) to set foot on the surface of the moon.