It's the mother of all conspiracy theories: the unflinching belief that the 1969 Moon landing never actually happened.

Proponents of this seemingly unshakeable conviction argue that what the masses perceived as a groundbreaking scientific achievement was in fact an elaborate fake: a hoax perpetrated by NASA and the US government on the American (and international) public at large.

With everything we know about the Apollo 11 mission and the mountains of evidence NASA makes available it's amazing this conspiracy theory is still alive and kicking in late 2018.

But there's a very good reason why it is.

Aside from all the psychological traps that make people susceptible to falling for conspiracy theories, one of the main reasons people keep suspecting the Moon landing was faked is because other people keep implying it was.

Case in point: Dmitry Rogozin, the head of Russia's national space agency, Roscosmos, just fed this unkillable rumour in a filmed meeting with the president of Moldova, Igor Dodon.

In a video of the exchange posted on Rogozin's Twitter feed on Saturday, the Roscosmos chief was asked whether NASA really did land on the Moon almost 50 years ago.

In response, Rogozin proposes a new Russian mission will investigate the controversial claims: "We have set this objective to fly and verify whether they've been there or not," he says.

While Rogozin's body language during the Q&A suggests he's actually joking as he says this – ad-libbing a gag about the long-lived conspiracy theory – it's not the first time Russia has raised doubts about details of the Apollo 11 mission.

In a 2015 article published in the Russian newspaper Izvestia, a spokesperson for the Russian Investigative Committee, Vladimir Markin, called for an international probe into the disappearance of film footage from the famous 1969 event, while querying the whereabouts of lunar rock samples collected by NASA up until 1972.

"We are not contending that they did not fly [to the Moon], and simply made a film about it," Markin wrote.

"But all of these scientific – or perhaps cultural – artefacts are part of the legacy of humanity, and their disappearance without a trace is our common loss. An investigation will reveal what happened."

These comments were made after the announcement of a probe into alleged FIFA corruption, with Markin criticising US prosecutors for "having declared themselves the supreme arbiters of international football affairs".

In that context, Markin's invoking of the conspiracy doubts is more a metaphor than a serious accusation, but it nonetheless all helps feed the distorted narrative that NASA somehow faked the 1969 landing.

For its part, NASA has been upfront about losing that original footage, and now its mismanagement of the tapes is all part of the faked landing fable.

According to the space agency, the original landing footage was misplaced among 200,000 video tapes that NASA intentionally wiped to save money.

To restore the missing footage, the space agency had to turn to Lowry Digital – a company that restores old Hollywood films – to replicate the original footage from broadcast video of the event.

Of course, that kind of outright evidence meddling – in the hands of professional Hollywood effects artists, no less – only fuels the conspiracy theory.

The irony of all this was not lost on those involved in the restoration.

"The conspiracy theorists are going to believe what they are going to believe," Lowry Digital COO Mike Inchalik told Reuters in 2009.