India's attempt at a soft lunar landing appeared to end in a crash on September 6 (September 7 in India), making it the second failed moon landing this year.
The mission's main spacecraft, Chandrayaan-2, has since spotted the Vikram lander's hapless hardware from its vantage point orbiting the moon. The lander arrived at the moon's south pole, seemingly in one piece, but India's space agency said it has been unable to restore communications.
Robert Braun, dean of the College of Engineering and Applied Science at the University of Colorado, has worked on landing and descent teams for multiple NASA missions to Mars.
"Among all the things we do in space, landing is one of the more challenging aspects, because time gets greatly compressed," he told Business Insider. "There's very little margin to try something again if it didn't happen as planned."
Here's why the final stages of a moon landing are so challenging.