The unique and innovative Spitzer Legacy Science Program was motivated by a desire to enable large observing programs early during Spitzer's prime mission, with the goal of creating a substantial database of archived observations that can be utilized by subsequent Spitzer observers. Legacy Science projects are distinguishable from General Observer investigations through these fundamental principles:|
They are large and coherent science projects, not reproducible by any reasonable number or combination of smaller General Observer investigations.
They are projects that are of general and lasting importance to the broad community and whose Spitzer data should yield a substantial and coherent database.
All raw and pipeline-processed data enter the public domain immediately upon SSC verification, thereby enabling timely and effective opportunities for follow-on observations and for archival research, with both Spitzer and with other observatories.
Traditionally, the term "Legacy program" was used to refer to the 'original' Legacy programs, e.g., those selected before launch. Though not specifically solicited, five Cycle-2 programs were selected that shared these fundamental principles, and were therefore retroactively also classified as Legacy programs. Starting in Cycle-3, Legacy GO programs are specifically solicited.