LONDON — Two former astronauts say they are disappointed with the U.S. government's decision to cancel NASA's moon landing program.

Eugene Cernan, part of the 1972 Apollo 17 mission, said he's disheartened he's the last man to have walked on the moon. "I thought we'd (have) gone back long before now."

Cernan said the U.S. has a responsibility to maintain leadership in space exploration, and he hopes people will be back on the moon "sooner than later."

Jim Lovell, who led the Apollo 13 mission in 1970, said "catastrophic consequences" impacting the exploration of space could result from the cancellation.

Cernan and Lovell spoke to the BBC on Friday in London.

The decision to cancel NASA's $100 billion Constellation program was announced last month.