The Mercury program did not send the first Americans to space. It was the Project Mercury program that sent the first Americans into space.

Here's a breakdown:

* Project Mercury: The first human spaceflight program in the United States, launched in 1958 and ran until 1963. It successfully sent Alan Shepard into space on May 5, 1961, making him the first American in space.

* Mercury program: This is a term sometimes used to refer to Project Mercury, but it's not the official name.

Therefore, the first Americans to go to space were sent on Project Mercury missions.