<P> A program of automated return vehicles was begun, in the hope of being the first to return lunar rocks . This had several failures . It eventually succeeded with Luna 16 . But this had little impact, because the Apollo 11 and Apollo 12 lunar landings and rock returns had already taken place by then . </P> <P> In total, twenty - four U.S. astronauts have traveled to the Moon . Three have made the trip twice, and twelve have walked on its surface . Apollo 8 was a lunar - orbit - only mission, Apollo 10 included undocking and Descent Orbit Insertion (DOI), followed by LM staging to CSM redocking, while Apollo 13, originally scheduled as a landing, ended up as a lunar fly - by, by means of free return trajectory; thus, none of these missions made landings . Apollo 7 and Apollo 9 were Earth - orbit - only missions . Apart from the inherent dangers of manned Moon expeditions as seen with Apollo 13, one reason for their cessation according to astronaut Alan Bean is the cost it imposes in government subsidies . </P> <Table> <Tr> <Th> Mission name </Th> <Th> Lunar lander </Th> <Th> Lunar landing date </Th> <Th> Lunar liftoff date </Th> <Th> Lunar landing site </Th> <Th> Duration on lunar surface </Th> <Th> Crew </Th> <Th> Number of EVAs </Th> <Th> Total EVA Time (HH: MM) </Th> </Tr> <Tr> <Td> Apollo 11 </Td> <Td> Eagle </Td> <Td> 20 July 1969 </Td> <Td> 21 July 1969 </Td> <Td> Sea of Tranquility </Td> <Td> 21: 31 </Td> <Td> Neil Armstrong, Edwin "Buzz" Aldrin </Td> <Td> </Td> <Td> 2: 31 </Td> </Tr> <Tr> <Td> Apollo 12 </Td> <Td> Intrepid </Td> <Td> 19 November 1969 </Td> <Td> 21 November 1969 </Td> <Td> Ocean of Storms </Td> <Td> 1 - day, 7: 31 </Td> <Td> Charles "Pete" Conrad, Alan Bean </Td> <Td> </Td> <Td> 7: 45 </Td> </Tr> <Tr> <Td> Apollo 14 </Td> <Td> Antares </Td> <Td> 5 February 1971 </Td> <Td> 6 February 1971 </Td> <Td> Fra Mauro </Td> <Td> 1 - day, 9: 30 </Td> <Td> Alan B. Shepard, Edgar Mitchell </Td> <Td> </Td> <Td> 9: 21 </Td> </Tr> <Tr> <Td> Apollo 15 </Td> <Td> Falcon </Td> <Td> 30 July 1971 </Td> <Td> 2 August 1971 </Td> <Td> Hadley Rille </Td> <Td> 2 days, 18: 55 </Td> <Td> David Scott, James Irwin </Td> <Td> </Td> <Td> 18: 33 </Td> </Tr> <Tr> <Td> Apollo 16 </Td> <Td> Orion </Td> <Td> 21 April 1972 </Td> <Td> 24 April 1972 </Td> <Td> Descartes Highlands </Td> <Td> 2 days, 23: 02 </Td> <Td> John Young, Charles Duke </Td> <Td> </Td> <Td> 20: 14 </Td> </Tr> <Tr> <Td> Apollo 17 </Td> <Td> Challenger </Td> <Td> 11 December 1972 </Td> <Td> 14 December 1972 </Td> <Td> Taurus--Littrow </Td> <Td> 3 days, 2: 59 </Td> <Td> Eugene Cernan, Harrison "Jack" Schmitt </Td> <Td> </Td> <Td> 22: 04 </Td> </Tr> </Table> <Tr> <Th> Mission name </Th> <Th> Lunar lander </Th> <Th> Lunar landing date </Th> <Th> Lunar liftoff date </Th> <Th> Lunar landing site </Th> <Th> Duration on lunar surface </Th> <Th> Crew </Th> <Th> Number of EVAs </Th> <Th> Total EVA Time (HH: MM) </Th> </Tr>

When was the last time we went to the moo