NASAs Apollo space mission were for the exploration of the moon. In 1969 Apollo 11 manned by Buzz Aldrin and Neil Armstrong, was the first one that allowed a moon walk. These two men were the very first astronauts to ever set foot on the surface of the Moon. In 1972 NASA launched their final Apollo mission; Apollo 17. There were altogether 20 missions scheduled for the Apollo mission. Apollo 18, Apollo 19 and Apollo 20 were coordinated, but were scrapped due to budgeting limitations.
Although there can be found on the internet plenty of erroneous reports of an Apollo 20 mission, Apollo 20 was cancelled on January 4th, 1970. The reason for its cancellation at that time was Skylab’s need for Apollo 20’s Saturn V rocket. Because of budget restrictions the Saturn V had a limited production; only the original 15 that were created.
One such erroneous report of Apollo 20 is linked to William Rutledge who had made claims that as a former scientist for Bell Laboratories and was working for the United States Air Force he had knowledge of a secret Apollo mission which was a joint project of the Soviets and Americans. It was also purported that Apollo 20 had discovered an alien craft on the surface of the Moon.
This conspiracy theory states that Apollo 20 made its moon visit on the 16th of August, 1976. This was just about 4 years later following the final Apollo mission. An impact crater on the Moons dark side, Delporte was the intended landing site. Along with Rutledge, Crew Members of this Apollo 20 mission were said to have included Leona Snyder and Alexei Leonov. They were sent to investigate an Alien craft that was apparently detected earlier by the crew of the Apollo 15 mission crew (James Irwin, David Scott and Alfred Worden) in 1971.
Alexei Leonov was indeed an astronaut; he was the first man to walk in space on the 18th of March, 1965. Leonov commanded the Apollo-Soyuz mission, which was the first space mission involving both the USA and the Soviets, on the Soviet side. In the book 2010: Odyssey Two by Arthur C. Clarke, Alexei Leonov the Cosmonaut was named for him. But Leonov never admitted to being a part of the Apollo 20 top-secret mission.
The astronauts visited an ancient city and an alien space craft on the Moon’s surface, if you believe Rutledge's story. The astronauts had also been able to collect some nifty alien gadgets and they even brought back one of the two deceased alien pilots to their Lunar landing module.
From analysis of the density of meteor impacts revealed the ship and ancient city were there for 1½ billion years. And the ship seemed to have been explored previously, perhaps by a different alien race.
This story probably had some inspiration from a similar story about some pictures taken while on the Apollo 15 mission. The images are genuine and can be found at the Universities Space Research Association webpage. You can see in the NASA images that there is an object that looks quite strange.
It is probably no more than optical illusion, but it’s quite interesting-looking. It’s a cigar-shaped object inside of a crater. A strange aspect is that it seems to have a shadow.