The third manned Gemini mission had a tough act to follow. During the previous mission astronaut Ed White had completed America's first walk in space, now Mercury veteran Gordon Cooper would take first timer, Charles "Pete" Conrad into orbit to see how long they could survive in the tiny Gemini spacecraft. The pair chose an image of a Conestoga wagon for their mission patch because they were going to be in orbit for eight days; effectively homesteading in space. If they succeeded, it would be the longest duration space flight to date.

Cooper was no stranger to long duration missions, having spent over 34 hours in the even smaller Mercury capsule, Faith 7.

Their mission plan included a substantial list of seventeen experiments which included medical, scientific and engineering tasks. The purpose of the mission was to see whether a crew could survive for eight days - the time it was expected to get to the moon and back - without any adverse effects. Gemini 5 was also carrying a small satellite that was to be ejected into space and used as a target for the new rendezvous radar that they were testing. Another brand new piece of equipment was also going to get its first use in space, the hydrogen fuel cell, which was expected to supply their electrical needs for the mission. Problems with this system would ultimately interfere with the planned rendezvous with the radar target.

Gemini 5 would be another major milestone in the development of manned spaceflight. Cooper and Conrad were a perfectly matched partnership, demonstrating their "right stuff" bona fides, while simultaneously keeping everyone involved with their mission entertained with their good humour.