Launch from Cape Canaveral (KSC); landing at White Sands, Runway 17, Northrup Strip. The launch was delayed one hour because of the failure of a heater on a nitrogen gas ground support line.

This mission was the third test flight of the Space Shuttle. For the first time, the External Tank was not varnished in white colour, as in the first two flights.

Payloads included the OSS-1 pallet in the cargo bay of the shuttle. OSS-1 obtained data on near Earth environment. Several other experiments (Monodisperse Latex Reactor, Heflex Bioengineering Test and more) were carried out.

The landing site changed to White Sands since the planned landing site at Edwards AFB flooded due to excessive rain. High winds at White Sands resulted in one day extension of the mission. STS-3 was the only shuttle mission to land at White Sands.