The Soviet Union was forced to concede defeat to the US 40 years ago when US astronaut Neil Armstrong landed on the moon, overshadowing earlier triumphs of the Soviet space programme.
The 1969 moon landing instantly became a signature achievement of American technical prowess, but in the Soviet Union its importance was played down by the authorities amid their Cold War rivalry with the US.
Experts say Moscow's failure to carry out its own manned moon mission reflected the inability of its space programme to develop past early successes like the first satellite launch in 1957 and Yury Gagarin's spaceflight in 1961.
"The Americans' main goal was competition with the Soviets around the lunar programme. Their victory in this was undoubtedly a highly significant event in the contest between the two systems," said Russian space expert Igor Lisov.
"Unfortunately we underestimated the Americans, we began too late and with insufficient resources," said Mr Lisov, editor of Cosmonautics News, a specialist journal on space exploration.
Problems with the Soviet space programme included overly ambitious technical goals and the "baroque" management of subcontractors, said Jacques Blamont, an adviser to the head of the French government space agency CNES.
But the main problem was "a battle of managers which was never settled at the political level," Mr Blamont said.
The Soviets "did not really have a strategic national direction" and had two duelling conceptions of their lunar programme, one that envisioned a moon landing and one that involved sending a probe around the moon, he said.
Moscow's failure to reach the moon was compounded by troubles with its "planetary" programme aimed at exploring Mars and Venus, which suffered a series of failures, Mr Blamont said.
However, ordinary Soviet citizens knew little about the failures, which were hushed up by the authorities, even as state propaganda glorified Mr Gagarin and other cosmonauts, turning them into living legends.
Mr Armstrong's first steps on the moon were not censored, but the authorities clearly tried to play down their significance and most Soviet citizens did not grasp the magnitude of the event.
Four decades later, few Russians will be celebrating the anniversary of the moon landing, said Mr Lisov, the editor of Cosmonautics News.
"Today few people are interested in this," he said. Of them, "there are two camps: Those who still think we lost and that this is sad, and those who seek consolation in the theory that the Americans were never on the moon."