The primary organizations responsible for the design, development, and operation of Spitzer were:

-- Jet Propulsion Laboratory
The Jet Propulsion Laboratory (JPL) in Pasadena, California was responsible for the overall management of the Spitzer Project, as well as the design, development, and implementation of the Spitzer Flight Operations System. JPL also provided system engineering and analysis support as needed by the various team organizations.

-- Lockheed Martin
Lockheed Martin Space System Company (LMSSC) in Sunnyvale, California was responsible for the design and development of the spacecraft, as well as Observatory Systems Engineering, Integration, and Testing (SEIT).

-- Ball Aerospace
Ball Aerospace and Technologies Corporation (BATC) in Boulder, Colorado was responsible for the design and development of the cryo-telescope assembly (CTA), as well as integration of the science instrument cold assemblies into the cryostat. BATC was also the subcontractor for the IRS and MIPS science instruments.

-- Smithsonian Astrophysical Observatory
The Smithsonian Astrophysical Observatory (SAO) in Cambridge, Massachusetts was responsible for the science and instrument requirements of the Infrared Array Camera (IRAC) science instrument, under the direction of Principal Investigator Dr. Giovanni Fazio.

-- NASA-Goddard Space Flight Center
NASA-GSFC in Greenbelt, Maryland was responsible for the design, fabrication, and testing of the IRAC hardware.

-- Cornell University
Cornell University in Ithaca, New York was responsible for the design and development of the Infrared Spectrograph (IRS) science instrument, under the direction of Principal Investigator Dr. James Houck.

-- University of Arizona
The University of Arizona in Tucson was responsible for the design and development of the Multiband Imaging Photometer for Spitzer (MIPS) science instrument, under the direction of Principal Investigator Dr. George Rieke.

-- Spitzer Science Center/Infrared Processing and Analysis Center/Caltech
The Spitzer Science Center (SSC) at the California Institute of Technology's IPAC Science and Data Center in Pasadena, California was responsible for the design, development, and implementation of the Spitzer Science Operations System.