Two Nasa space probes have crashed into the surface of the Moon after their planned mission came to an end.
The two spacecraft, Ebb and Flow, have been orbiting the Moon since their launch in September 2011 to create a gravity field map of its surface.
But, with not enough fuel to carry out further experiments, the American space agency opted for a "controlled descent" to avoid the risk of obliterating astronaut Neil Armstrong's footsteps on the Moon.
Ebb plunged first, slamming into a mountain near the Moon's north pole. Its twin, Flow, followed about 30 seconds later and aimed for the same target.
After the double impacts, mission chief scientist Maria Zuber of the Massachusetts Institute of Technology said the spot had been named after team member Sally Ride, the first American woman in space, who died earlier this year.
"It's really cool to know that when you look up now at the Moon there's this little corner of the Moon that's named after Sally," said Ms Ride's sister.
Since the crash site was in darkness, the final act was not visible from Earth.
The Lunar Reconnaissance Orbiter, which is circling the Moon, will pass over the mountain and attempt to photograph the skid marks left by the washing machine sized-spacecraft as they hit the surface at 3,800mph.