On re-entry Casper hit the atmosphere at an altitude of about 400,000 feet above the earth and at a velocity of nearly 25,000 miles per hour.
The LM eventually crashed due to lunar gravity anomalies. Since Houston didn’t know exactly where it landed, it was not useful to calibrate seismic experiments on the surface.
It was the only time in their whole lunar stay that Charlie had a real moment of panic and thought he had killed himself.
The crew nicknamed this operation “The Big Sneak.” They figured the only way to do this was to approach from behind a big rock, then reach over and collect the sample.