The Launch Date was the set date for Andromeda's plans to launch their technology. The plan was to upload their radio wave program (the product of Eugene Meltsner's research) to radio stations all around the world via satellite. When Whit and Tom found the launch site, Whit was discovered and lured away from the site by Mr. Charles. With Jason's guidance, Tom found the Imagination Station as part of the up-link, and Whit was able to give Tom the password Applesauce, which was still buried in the Station's archives, destroying the Station and thwarting the Launch Date.
According to both Arthur Dent and The Chairman, the Launch Date was supposed to be the culmination of years of work.