Apollo 9, launched on March 3, 1969, was the third manned mission of Project Apollo. It was the first space test of the complete Apollo spacecraft in low Earth orbit, crewed by Mission Commander James McDivitt, Command Module Pilot David Scott and Lunar Module Pilot Rusty Schweickart. For 10 days, the crew performed a series of test including the Lunar Module and Command/Service Module docking maneuvers, EVA, and the new Apollo spacesuit.
Apollo 9 launch, with official NASA/KSC cachet, signed by James McDivitt, David Scott & Rusty Schweickart.
Apollo 9 "Orbit Covers" postmarked on launch day, signed by James McDivitt, Rusty Schweickart & David Scott.

Front and back of Apollo 9 postcard cancelled on the prime recovery ship USS Guadalcanal.