If you probe something, you investigate it thoroughly. If you go into business with someone, you might probe her finances to make sure that she has a good track record.
Although it is usually used as a verb — "the police probed the man’s disappearance" — it can also be used as a noun to describe an information-gathering device. In 1979 the United States launched the world's first space probe into outer space. It was a spacecraft rigged with cameras, which were used to photograph Jupiter and Saturn.