AS-202 (or SA-202) was a sub-orbital test flight of the Saturn IB and Command and Service Module. It is sometimes informally called Apollo 3.
AS-202 was the second test flight of the Saturn IB. It was designed to test the rocket more than had been done on AS-201 by launching the rocket higher and having the flight lasting twice as long. It would also test the Command and Service Module (CSM-011) by having the engine firing four times during the flight.
The flight was also designed to test out the heat shield by subjecting it to 260 megajoules per square metre. Over the course of the reentry it generated equivalent energy needed to power Los Angeles for over one minute in 1966.
CSM-011 was basically a production model capable of carrying a crew. However it lacked the crew couches and some displays that would be included on later missions for the astronauts. This was the first flight of the guidance and navigation system as well as the fuel cell electrical system.