The Ark ship crash-landed on the Moon, severely damaging its structure.
Humans have hidden many things, even to the extent that their own measures for secrecy and subsequent personnel changes left them unaware of what was here:
The work concerning extraterrestrials was handled by an organization called "Zone 7," but this agency wasn't part of the government sequence, reporting only directly to the President who established it. It was only two years ago, when Transformers began to appear, that the President became aware of its existence.
But after the great battle two years ago, Zone 7 was dissolved, and many files were sealed away. The intelligence personnel who received them didn't know where to start organizing the information.
This led to a significant oversight, as the Autobots were unaware that there was another ship that had landed here long ago.
