Simplify the following text for a Grade 4 native English-speaking person.
Original: The 14,562 acre ( 58.93 kmÂ or 22.753 sq mi ) island is currently controlled by the United States Navy and is used as a weapons testing and training facility , served by Naval Outlying Field San Nicolas Island .
Simplified: The 14,562 acre ( 58.93 kmÂ or 22.753 sq mi ) island is used by the United States Navy for a weapons testing and training .