Beyond this historical context, it can sometimes be used loosely when someone achieves a long-desired objective or significant milestones or reaches the zenith of a challenging adventure.
What does the eagle has landed mean?
"The Eagle Has Landed" is most commonly known for representing the successful landing of Neil Armstrong and Buzz Aldrin's lunar module Eagle during the Apollo 11 mission when humans first went to the moon on July 20, 1969. Mission Commander Armstrong radioed to Earth with these four words when Eagle made lunar contact in the Sea of Tranquility.