Q: Who operates SOFIA?

A: SOFIA is a joint project between NASA and the German space agency Deutsches Zentrum für Luft und Raumfahrt (DLR). It is operated out of the NASA Ames Research Center (ARC) and the Dryden Airborne Operations Facility (DAOF) by a consortium consisting of the NASA Dryden Flight Research Center (DFRC), ARC, Universities Space Research Association (USRA) and the Deutsches SOFIA Institut (DSI). USRA SOFIA operations are headquartered at Ames, and DSI is headquartered at the University of Stuttgart.

Q: Why are there two centers? Wouldn't it be easier to operate the mission from one place?

A: The SOFIA Science Center (SSC) is located at NASA Ames. The SOFIA Operations Center (SOC) and the aircraft itself are located at the Dryden Airborne Operations Facility (DAOF). This maximizes the utilization of expertise -- astronomy at Ames and airborne operations and maintenance at Dryden.

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Q: When will SOFIA have full operational capability?

A: SOFIA is expected to have full operational capability by 2014. The capability will start ramping up quickly after the Early Science phase in 2009-2010.

Q: How will the price of gasoline affect SOFIA operations?

A: The allocated budget for fuel includes a significant margin to account for inflation in fuel prices. We do not anticipate any impact on flight and telescope operations.

Q: Who will be present on the aircraft while the telescope is in operation?

A: There will be the flight crew (pilot, co-pilot and flight engineer), the science crew (flight director, telescope operator, instrument scientist, and sometimes a support scientist), the investigator crew (drawn from program PI and CoIs) and members of the "Airborne Astronomy Ambassador" program (teachers affiliated with the SOFIA EPO program).

Q: Is SOFIA expected to land and take-off routinely from several airfields? If so, where are they all located?

A: SOFIA will be based at, and operate out of, the Palmdale municipal airport, associated with NASA Dryden. The aircraft will be flown out of other locations when it is necessitated by the science (for example, observations in the southern hemisphere, or to target transient events such as occultations). Eventually there will be regular, annual deployment from some base (yet to be determined) in the southern hemisphere. The aircraft is a modified Boeing 747, and hence be able to fly in and out of most major airfields.

Q: How long will individual flights last?

A: Individual flights will last between 8 and 10 hours.

Q: I have been hearing of SOFIA for many years. Why has it taken so long for it to get operational?

A: Retrofitting a Boeing-747 for use as an airborne observatory is a major technological challenge; for instance, the aircraft has to fly with a 2.5 meter aperture in the fuselage, where the telescope will be housed. Technological and financial challenges have kept SOFIA a long time in the making. We note that in the last two years, the project is running within 2 months of the nominal schedule.

Q: Who will be present on the aircraft while the telescope is in operation?

A: There will be flight crew (pilot, co-pilot and flight engineer), a science crew (flight director, telescope operator, instrument scientist, and sometimes a support scientist), investigator crew (drawn from program PI and CoIs) and members of the "Airborne Astronomy Ambassador" program (teachers affiliated with the SOFIA EPO program).

Q: How large is the telescope?

A: The primary mirror of the telescope has a diameter of 2.7 meters, with an effective aperture of 2.5 meters.

Q: What is the optical design of the telescope?

A: The telescope is a Cassegrain with Nasmyth focus.

Q: What is the wavelength coverage of the telescope, and what is its angular resolution?

A: The wavelength coverage is 0.3 - 1600 micron. The image will be diffraction limited above 15 micron. The instrumentation and science is expected to focus on the mid and far-infrared portion of the bandpass.

Q: Will SOFIA be operated like a ground-based observatory, or more like a space-mission?

A: SOFIA will have characteristics of both, including most of the advantages of each. The operations schedule and support for observers (including funding) will be similar to those of space missions. The maintenance of the telescope and instruments will be carried out on the ground. This will allow for the continued development and use of new instruments much as in a ground-based observatory.

Q: How many instruments are currently available?

A: Nine first-generation instruments will fly on SOFIA. Of these FORCAST and GREAT will be the first two available.

Q: How many instruments fly on the plane at a given time?

A: Typically, only one instrument will fly at any given time. The only exception is that FLITECAM and HIPO can fly at the same time.

Q: When will new instruments be developed for SOFIA?

A: There will be a call for proposals for US instruments that will be made in 2010 for second generation instruments. However, there may be other opportunities for instrument development that may arise as the mission matures.

Q: Will current instruments be "retired" or will they always be available for use?

A: The instruments, especially the Facility-class Science Instruments, will be available for use as long as they perform state-of-art science observations. They may be temporarily withdrawn for upgrades and modifications. However, no instrument will be automatically retired based on their duration-of-service.

Q: How is instrument development funded?

A: For US instruments, NASA Headquarters will be responsible for issuing Announcements of Opportunity for SOFIA Science Instrument and Technology Development. NASA HQ will also be responsible for selecting the funding vehicle.

Q: Can anyone propose designs for new instruments?

A: There is no restriction on who can propose designs for new instruments beyond any that may be included in the relevant NASA Announcement of Opportunity. However, only persons in US based institutions can receive NASA funding.

Q: How many hours of science observations is SOFIA expected to make each year?

A: During the "Full Operations Capability" period, expected to start in 2014, the goal is for SOFIA to carry out 960 hours of science observations each year.

Q: Will SOFIA have access to all parts of the sky?

A: Yes, SOFIA will have access to all parts of the sky. The plan is for SOFIA to be deployed from a base in the southern hemisphere for several months each year. This will be implemented as the mission ramps up towards Full Operations Capability.

Q: How will observations be scheduled? Will there be a long-range plan?

A: Observations will be scheduled based on an approved, prioritized target list and on flight plans. There will be a long-range plan.

Q: Will SOFIA have a guest observer program?

A: Yes, SOFIA will have a program for guest observers, who will be called "General Investigators". In regular operations, there will be two independent calls for SOFIA observing each cycle: one for the US portion (80%) of the observing time and the other for the German portion (20%). The US Guest Investigator program will be co-ordinated by USRA, the German program by DSI.

Q: Where can I find details about how and when to propose?

A: Proposal calls for the US Guest Investigator program, along with details of how to submit proposals will be posted on the SOFIA web site, http://www.sofia.usra.edu/Science/proposals/.

Q: Will there be funding for General Investigators?

A: USRA will provide funding for those General Investigators selected through the US call for proposals and who are affiliated with US based institutions.

Q: Do General Investigators have to collaborate with instrument PIs, or SOFIA scientists?

A: General Investigators (GIs) do not have to enter into collaboration with either SOFIA scientists or instrument PIs when using Facility-class Science Instruments (FSIs) and Principal Investigator-class Science Instruments (PSIs). However, Special Purpose Principal Investigator-class Science Instruments (SSIs) designed for particular sets of observations will have restricted availability. Interested GIs would need to contact the instrument team and partner with them, at their discretion.

Q: Will SOFIA have any kind of program with other facilities, so that joint proposals may be submitted?

A: Currently, there are no plans for any specific joint programs. This may change as SOFIA approaches full operations capability.

Q: Will Guest Investigators with approved proposals be allowed to fly on the SOFIA aircraft?

A: Yes, Guest Investigators will be allowed to fly on SOFIA.

Q: Will Guest Investigators be required to fly, in some cases?

A: No, Guest Investigators will not be required to fly. SOFIA support scientists will be available to carry out the observations if the Guest Investigator cannot be on the flight.

Q: Where, and in what form will the data be archived?

A: The data obtained by SOFIA will be archived at the SOFIA Science Center. The data will be stored in FITS format.

Q: Will the archive of science data be available to the astronomical community, and more generally to the public?

A: Yes, the science data (after the mandated proprietary periods) will be available to the public. Users will be requested to register on-line before downloading data. The registration will help us maintain usage statistics.

Q: Will the archived data be ready to use for scientific analysis?

A: The archived data from the Facility-class Science Instruments will be ready to use for scientific analysis. In the case of PI-class Science Instruments, the current expectation is that only the raw data will be archived.

Q: Will the data reduction pipelines for the various instruments be publicly available?

A: No, the data reduction pipelines will not be publicly available. This is mainly due to a lack of resources for this activity.

Q: Will there be persons at the SOFIA Science Center who will be assigned to help astronomers process and/or analyze data?

A: No, at this time we do not expect to have enough resources to help Guest Investigators with data processing. However, we do plan to hold SOFIA data workshops regularly (including at AAS meetings).

Q: Will SOFIA have a funded archival study program?

A: Yes, SOFIA will have a funded archival study program.