Sentence:  If you look for your new object after discovery, it's called "recovery". [...] if you find your new object in some old data that someone took before you discovered your object, it's called a "<WSD>precovery</WSD>". 
Meaning of the word marked with <WSD> tags:  The use of previously gathered data (especially photographic images) to recover a recently discovered object (typically a small solar system body).