2.1 History and Organization of the Spitzer Project
The Spitzer Space Telescope began life as the Shuttle Infrared Telescope Facility (SIRTF) at the NASA Ames Research Center in 1971. The early history and subsequent development are described in detail by G. Rieke (2006, “The Last of the Great Observatories,” Univ. Arizona Press) and by R. Rottner (2017, “Making the Invisible Visible”, NASA SP-2017-4547). Key milestones in this history are:
June 1984: Selection of SIRTF instrument teams and Science Working Group.
1988: Decision to implement SIRTF in High Earth Orbit.
January 1990: Transfer of management responsibility for SIRTF from NASA Ames to JPL/Caltech.
1991: SIRTF selected as highest priority space astronomy mission for the 1990’s by the decadal review panel chaired by John Bahcall.
Spring 1993: Selection of earth-trailing solar orbit for SIRTF.
November 1993: Adoption of warm launch architecture for SIRTF.
1995: Release of Request For Proposal (RFP) for selection of SIRTF contractors.
June 1996: Announcement of results of selection; formation of SIRTF project team.
August 1996: Designation of the Infrared Processing and Analysis Center (IPAC) at Caltech as the home of the SIRTF Science Center.
September 1997: Initiation of SIRTF Phase C/D – formal beginning of construction of SIRTF.
November 2000: Selection of the first SIRTF Legacy Science programs – large programs which established new modes of community participation in NASA missions.
August 25, 2003: Launch of SIRTF.
December 2003: Release of first SIRTF data and renaming of SIRTF as the Spitzer Space Telescope, to honor Lyman Spitzer, Jr.
September 2004: Publication of first Spitzer results in v.154 of the Astrophysical Journal Supplement.
May 2009: Depletion of Spitzer cryogen and end of the Cryogenic Mission.
July 2009: Start of Spitzer Warm Mission.
October 2016: Start of the Spitzer Beyond Mission.
January 29, 2020: Final observations executed
January 30, 2020: Decommissioning of the Spitzer Space Telescope, 6002 days since launch.
Although it took many years for Spitzer to go from Science Working Group/instrument selection to project start in 1996, the intervening years were not wasted; indeed, during this time the three instrument teams engaged in intensive detector technology development activities, resulting in an ensemble of focal plane arrays which achieved natural-background-limited performance even when used on a cryogenic space telescope. In the final realization, the teams used these arrays in ways which simplified instrument design and reliability. During this same time period, a very effective cryogenic optics development program led to a prototype all-beryllium telescope which was converted to the flight telescope after the selection of the contractor team.
The project organization for the development phase from 1996 to 2003 is shown in Figure 2.1. Ball Aerospace, which built the Cryogenic Telescope Assembly, including the telescope, cryogenic system, and associated shields and shells, was one of two major industrial partners. Ball also built the scan mirror mechanism for MIPS and was the contractor working with Cornell and U. Arizona to build the IRS and MIPS instruments, respectively. The other major industrial partner was Lockheed Martin Sunnyvale, which provided the spacecraft, the solar panel, and the system engineering, integration, and test for the observatory. NASA Goddard Space Flight Center was contracted by Harvard-SAO to build the IRAC instrument. The instrument Principal Investigators and their institutions are listed in Section 2.3 below. Spitzer had no foreign partners during the development phase, although scientists from across the world have applied successfully for observing time on Spitzer during the operations phase.
Figure 2.1: Spitzer Project organization during development phase 1996 - 2003. This diagram portrays functional responsibilities rather than reporting paths.
The launch of Spitzer was followed by two-month in-orbit checkout and one-month science verification phases which were paced by the cool down of the telescope. Execution of the Spitzer science program began on 1 December 2003, and the first public data release and naming of the observatory occurred later that month. During this time, the project organization was changed to one more appropriate for the operations phase of the mission, as is shown in Figure 2.2. In this transition, Lockheed Martin Sunnyvale was superseded by Lockheed Martin Denver, who took responsibility for spacecraft operations. Ball Aerospace monitored the performance of the cryogenic system and estimated the amount of helium remaining. Day-to-day responsibility for the science instruments was transferred, by pre-agreement, from the instrument teams to the Spitzer Science Center. The Ball Aerospace support ended with the depletion of the helium and the transition to the Spitzer warm mission. Also at this time, the operational responsibilities of the Spitzer Science Center for the IRS and MIPS instruments terminated since they were not used in the warm mission.
Figure 2.2: Spitzer Project organization during operations phase, 2003-2020. This diagram portrays functional responsibilities rather than reporting paths.
Spitzer was supported within NASA by the Astrophysics Division of what is now called the Science Mission Directorate. Programmatically, Spitzer completed NASA’s family of Great Observatories, which also includes the Hubble Space Telescope, the Chandra X-Ray Observatory, and the Compton Gamma Ray Observatory (superseded by the Fermi Gamma Ray Telescope). Like its sister Great Observatories, Spitzer was operated as an observatory for the entire scientific community, with the bulk of the observing time (>80% during the cryogenic mission; 100% during the warm mission) available to the international scientific community through a peer-reviewed time allocation process.
A largely complete list of the many people who worked on the Spitzer project development and thus contributed to the great success of Spitzer is given in Werner et al. (2004) and updated at the end of this document in Appendix C. However, it is appropriate here to single out the six outstanding Project Managers who led the project during development and operations. These are: Larry Simmons who served from 1993 to 1999, David Gallagher (1999-2004), Robert Wilson (2004-2010), Suzanne Dodd (2010 - 2016), Lisa Storrie-Lombardi (2016-2019) and Joseph Hunt (2019-2021).
Overviews of the Spitzer mission during the cryogenic phase are given by M. Werner et al. (2004, ApJS, 154, 1) and by R. Gehrz et al. (2007, Rev. Sci. Inst., 78, 1302). The scientific bounty of Spitzer is described by M. Werner and P. Eisenhardt in “More Things in the Heavens: How Infrared Astronomy is Expanding our View of the Universe”, published by Princeton University Press in 2019.
