When the National Academy of Sciences declared the Spitzer Space Telescope the highest-priority new initiative in astronomy and astrophysics for the1990s, the mission's total development cost totaled roughly $2.2 billion. However, the observatory has since undergone radical changes in design to meet evolving cost constraints.

Moreover, ongoing advances in the technology of infrared detectors, coupled with innovative choices in orbit and the design of cryogenic systems, have maintained the scientific vitality of the telescope at roughly one-third the original cost estimate.

Major innovations include: Infrared Detector Developments, Clever Choice of Orbit, Store and Dump Telemetry, and Project Management.