Spitzer Documentation & Tools
Spitzer Telescope Handbook


2.3            Principal Investigators, Science Team, and User Community

Initially, only six scientists were selected for the Science Working Group, three instrument PIís and three at-large members.† These were:


Giovanni Fazio, Harvard-SAO, PI for the Infrared Array Camera (IRAC)

Jim Houck, Cornell, PI for the Infrared Spectrograph (IRS)

George Rieke, U. Arizona, PI for the Multiband Imaging Photometer for SIRTF (MIPS)

Mike Jura, UCLA, Interdisciplinary Scientist

Frank Low, U. Arizona, Facility Scientist

Ned Wright, UCLA, Interdisciplinary Scientist


In addition, these scientists were joined on the SWG by three ex-officio members:†††

Nancy Boggess, NASA-HQ, Program Scientist

Mike Werner, NASA-Ames, Project Scientist and SWG Chair

Fred Witteborn, NASA-Ames, Deputy Project Scientist

2.3.1       Evolution of the Spitzer Science Working Group

The SWG remained remarkably stable over the ~20 years between selection and launch.† The only original member who left the group was Deputy Project Scientist Fred Witteborn, who did not make the move to JPL when the SIRTF project was relocated in 1989-1990.† However, several new members were added to the group Ė both to supplement the existing group and fill additional needs.† Thus at launch the SWG had expanded to 13, including the Project Scientist (Werner) and his new Deputy.† The new members were:


Dale Cruikshank, NASA-Ames, Planetary Science Representative

Robert Gehrz, U. Minnesota, Outreach Coordinator

Charles Lawrence, JPL, Deputy Project Scientist

Marcia Rieke, U. Arizona, Community Affairs Coordinator

Tom Roellig, NASA-Ames, Facility Scientist

Tom Soifer, Caltech, Director of the Spitzer Science Center [ex-officio]


In addition, the NASA Program Scientist has remained an ex-officio member of the SWG. A number of excellent NASA scientists, or detailees, have held that position over the years, and the SIRTF/Spitzer project has benefitted from their participation and oversight. They are: Bill Danchi (current), Jay Frogel (at launch), Jonathan Gardner, Doug Hudgins, Dave Leisawitz, Eric Smith, and Kimberly Weaver.


Although the instrument PIís have a business and contractual relationship to the Project Office, the SWG as a group has only an advisory role.† Formally, the SWG makes recommendations to the Project Scientist concerning scientific and technical matters, and the Project Scientist passes these on to the Project manager, or brings to the SWG questions raised by the Project Manager. In practice, the non-PI SWG members were well-integrated into the activities of the Project Office and often headed important project-wide tiger teams and integrated product teams.† In addition, the SWG played an extremely important role in SIRTF advocacy.† Finally, each member of the SWG was allocated observing time on Spitzer (see below) and was responsible for defining scientific programs, analyzing data and publishing the results.

2.3.2       Spitzer Scientific Utilization

Most of the observing time on Spitzer during the cryogenic mission (and all the time during the warm mission) was awarded to the international astronomical community through the usual peer-review process, which is managed by the Spitzer Science Center.† Four somewhat distinct categories of observing time were identified in during the cryogenic mission:†


Guaranteed Time was awarded to the PIs on behalf of their instrument teams and to the other members of the SWG.† During the first 2.5 years of the cryogenic mission, each instrument team was granted 5% of the observing time, which was shared among the two-to-three dozen scientists who were affiliated with each of the instrument teams.† The non-PI members of the SWG, including the Project Scientist and his Deputy, shared equally in another 5% of the time.† Two and one-half years was singled out for this purpose because it was the Spitzer Level 1 lifetime requirement (considerably exceeded by the actual cryogenic lifetime).† Following the first 2.5 years, the instrument team share continued at 5% while the non-PI allocation ceased.†


Directorís Discretionary Time amounts up to 5% of the observing time.† It is awarded at the discretion of the SSC Director to facilitate observations of new or time-critical phenomena which cannot be deferred to the next annual proposal cycle.† It continues at the 5% level during the Warm Mission.


Legacy Science Program is an innovation in community utilization which was pioneered by Spitzer.† The intent was to assure that Spitzer addressed critical scientific problems while producing a coherent legacy in the form of uniform, high quality databases of broad scientific interest.† This was done by inviting proposals for large programs and funding the selected teams both to produce scientific papers and to create higher order data products which go far beyond the standard data products produced by the SSC.† In the first Legacy selection, announced in 2000, six projects were selected and awarded a total of 3160 hours of Spitzer time, with over 700 hours going to the largest program.† These programs were largely completed during the first year of the Spitzer mission, and additional Legacy programs were selected and carried out annually for the next four years until the completion of the cryogenic mission.† During the Warm Mission, the spirit of the Legacy Science program is being carried on in the Exploration Science program, which has awarded over 10,000 hours of Spitzer time to 10 large programs; the largest of which will use over 2,000 hours.


General Observer (GO) projects.† All observing time on Spitzer not allocated into one of the previous three categories is awarded to General Observer projects, which cover a very wide range of scientific topics.† These can include joint projects with other NASA observatories.† The GO program continues during the Warm Mission, utilizing all observing time (except the 5% Directorís Discretionary Time).† In aggregate, including both GO and Legacy Projects, 747 scientists from 38 countries were selected as Principal Investigators on programs over the 5.7 years of the Spitzer cryogenic mission.



IPAC Caltech
Jet Propulsion Lab NASA