MOSCOW, Oct 14, 2024 (AFP) - The Kremlin denied on Monday that its space programme was falling behind after US firm SpaceX successfully flew a rocket booster back to the launch pad in a world first.

The first stage booster of SpaceX's Starship megarocket made a picture-perfect return to the launch tower on Sunday, in a test flight Elon Musk's company hailed as a day for the "history books".

Kremlin spokesman Dmitry Peskov said he "disagreed" with the idea Russia's own space programme was not developing fast enough after a series of mission failures.

"Space research is a rather sluggish process, it cannot unfold visually right before your eyes," Peskov said, adding that Russia was watching the US space programme with "great interest".

Once a space-faring pioneer, Moscow has faced multiple setbacks since the collapse of the USSR, including the loss of two Mars missions and its first lunar probe in almost 50 years in 2023.

Russia has many, often extravagant ideas to develop its space programme, including putting a nuclear reactor on the Moon with China, but has struggled to put them into action due to a loss of scientific talent and erratic funding.

Its Roscosmos space agency still ferries American astronauts to the International Space Station (ISS) -- one of its few areas of cooperation with the United States -- although it has signalled it wants to leave the project by 2028.

The head of Roscosmos warned last year that most Russian equipment on the station was beyond its "warranty" and that the ISS as a whole was "approaching the finish line of its existence".

The Russian segment of the orbital station has suffered three coolant leaks in just under two years, raising questions about the reliability of the country's space programme.