Launch from Cape Canaveral; landing close to the Bermuda Islands in the Atlantic Ocean.

Originally Clifton Williams was the lunar module pilot for the backup crew. He died on October 05, 1967, in a T-38 crash. His spot was given to Alan Bean. Later, when the backup crew flew Apollo 12, a fourth star was added to their mission patch in remembrance of him.

Apollo 9 was the first space test of the complete Apollo spacecraft, including the third critical piece of Apollo hardware besides the Command/Service Module (CSM) and the Saturn V launch vehicle—the Lunar Module (LM). It was also the first space docking of two vehicles with an internal crew transfer between them. For ten days, the astronauts put both Apollo spacecraft through their paces in Earth orbit, including an undocking and redocking of the lunar lander with the command vehicle, just as the landing mission crew would perform in lunar orbit. Apollo 9 gave proof that the Apollo spacecraft were up to this critical task, on which the lives of lunar landing crews would depend.

The crews of this and the following Apollo missions were allowed to name their own spacecraft (that happened the last time with Gemini 3). The gangly lunar module was named "Spider", and the command module was labelled "Gumdrop" on account of the blue cellophane wrapping in which the craft arrived at KSC.

Apollo 9, the third manned mission in the American Apollo space program, was the first flight of the Command/Service Module (CSM) with the Lunar Module (LM). Its three-person crew, consisting of Commander James McDivitt, Command Module Pilot David Scott, and Lunar Module Pilot Russell Schweickart, tested several aspects critical to landing on the Moon, including the LM engines, backpack life support systems, navigation systems, and docking maneuvers. The mission was the second manned launch of a Saturn V rocket.

An EVA was performed on March 06, 1969 by Russell Schweickart (1h 08m), checking out the new Apollo spacesuit, the first to have its own life support system. His only connection to the LM was a 25-foot nylon rope to keep him from drifting into space. Russell Schweickart walked between the LM and CSM hatches, maneuvered on handrails, took photographs, and described rain squalls over KSC; David Scott in a stand-up-EVA (1h 08m) filmed him from the command module hatch.

On March 07,1969 with James McDivitt and Russell Schweickart in the LM, David Scott separated the CSM from the LM and fired the reaction control system thrusters to obtain a distance of 5.5 kilometers between the two spacecraft. Both astronauts then performed a lunar module active rendezvous. The LM successfully docked with the CSM after being up to 183.5 kilometers away from it during the six-and-one-half-hour separation. After James McDivitt and Russell Schweickart returned to the CSM, the LM ascent stage was jettisoned. The crew performed also additional scientific work (i.e. photography of Earth surface). All the main goals of this mission were successfully accomplished.

As a result of unfavorable weather in the planned landing area, Apollo 9 completed an additional orbit before returning to Earth. The crew was recovered by the USS Guadalcanal.