The spaceship had always been there. Or so it seemed. It had landed so long ago that it was now classified as a prehistoric monument. There were even tourist trips.
“Our delightful ancestors had no interest in investigating the artefact or seeing if they could communicate with it,” explained our tour guide, “they simply tried to destroy it with their primitive nuclear weapons. However, as you see, it is still in pristine condition and, sadly, we now think it is empty. Its purpose will probably never be known.”
A little boy tugged at his mother.
“Look, Mummy, the door’s opening.”
Author’s note: Aliens who live for millennia would probably take their time working through the pre-EVA checklist.