I’m not sure for manned missions – Simon is the guy to ask for that!
For unmanned missions, several years for most. Satellites are designed very carefully, and their mission worked out to very high detail before they’re even built usually. This is to avoid any surprises or unexpected thigns when the satellite is in space!
For missions to ISS, the planning starts to solidify about 15months to a year before the start of an Increment. An increment is a period of 4 to 6 months usually beginning and ending with the undock of a Soyuz.
However certain elements of an increment take longer to prepare: Crew training is about 2 years and then of course the payloads, experiments of other equipment that we fly may take up to several years to design, build and test before launching. However some experiments can be made ready much quicker: only in a few months but these are very rare!
And for scientific experiments it can take years. You have to pitch the experiment to ESA or NASA, then it’s back and forth with engineers to get things approved to fly. The experiment I’m on has been about six years in the making.
Comments