The launch of Apollo 16 was delayed one month from March 17 to April 16. This was the first launch delay in the Apollo program due to a technical problem. During the delay, the space suits, a spacecraft separation mechanism and batteries in the lunar module (LM) were modified and tested. There were concerns that the explosive mechanism designed to separate the docking ring from the command module (CM) would not create enough pressure to completely sever the ring. This, along with a dexterity issue in Young's space suit and fluctuations in the capacity of the lunar module batteries, required investigation and trouble-shooting. In January 1972, three months before the planned April launch date, a fuel tank in the command module was accidentally damaged during a routine test. The rocket was returned to the Vehicle Assembly Building (VAB) and the fuel tank replaced, and the rocket returned to the launch pad in February in time for the scheduled launch.