They were the pioneers of space exploration - the 24 Nasa astronauts who travelled to the Moon in the Apollo missions of the 1960s and 1970s. The loss of Apollo 13 commander Jim Lovell, who guided the stricken mission safely back to Earth in 1970, means there are now just five people remaining who have escaped the relative safety of Earth orbit and ventured deeper into space. Now, more than 50 years on, the race to put people back on the lunar surface is heating up once again. Nasa hopes its Artemis programme will lead to astronauts living on the Moon this decade. China is also aiming to have people on the lunar surface by 2030, having landed a probe on the far side of the Moon in June 2024. A number of private companies have tried to send scientific craft to the Moon, although the mishaps have outnumbered the successes. Nasa had intended to launch Artemis 2, its first crewed lunar expedition since Apollo 17 in 1972, last year but that date has slipped into 2026, as the space agency says it needs more time to prepare. Meanwhile, companies such as SpaceX and Boeing continue to develop their own technology, although not without their setbacks. The issues with Boeing's Starliner which left two astronauts stranded on the International Space Station were embarrassing for the aerospace giant, while the "rapid unscheduled disassemblies" of SpaceX's Starship have become a customary sight to space watchers. These delays highlight the sad fact that the number of remaining Apollo astronauts is dwindling.