SOFIA Director's Discretionary Time

Suggestions for Director's Discretionary Time (DDT) observing projects are welcome at any time. Up to 7% of the observing time may be used for such projects. By default, any surplus DDT is used for already-accepted proposals from the annual proposal Call. Usages for DDT, as opposed to the normal annual proposal Cycle, may include the following:

  • Newly discovered celestial phenomena, such as stellar explosions or new comets. Be sure to check the list of approved Target of Opportunity programs from the current Cycle to see if your idea is potentially covered, and consider contacting the proposer or Director to find out if it is already being done.
  • Time-critical observations in support of other projects or missions that were not anticipated duing the prior Call.
  • Experimental techniques for which pilot observations are needed.
  • Observations that fill gaps in flight plans that would otherwise be "dead legs".

Other possibilities not included in this list may be considered by the Director, so please feel free to inquire directly.

Inquiries to the Director on this matter will be confidential unless mutually decided otherwise. DDT proposals will be handled in a manner similar to regular proposals, so the documentation from the previous or current Call for Proposals should be consulted. This document describes only policies and procedures specific to DDT. To request a DDT observation on SOFIA, please follow this procedure:

  1. Write a brief scientific case, approximately 2 pages plus 1 page of Figures. Included should be a brief background (with references that can allow us to learn context), description of the proposed project objectives, the observing plan, and a clear explanation of why the observations could not have been submitted as part of the previous Call and could not wait for the next Call. Put all this information into a single PDF file.
  2. Send the proposal as an email attachment to the SOFIA SMO Director, Harold Yorke ( ). The subject of the email should be "DDT request" and the body should contain your full contact information.
  3. Send a notification email to the help desk: telling us that a proposal has been submitted. In the subject of the email please put "DDT request." In the body of the email please include the proposal title and full contact information for the Principal Investigator of the proposal. This email will notify the User Support staff that a proposal exists and will ensure it is acted upon.

A list of accepted DDT projects is here.

Once accepted, a DDT project will quickly enter Phase II (described in the annual Calls), wherein a detailed observing plan is developed with the relevant Instrument Scientist. Flight planners will assess how to accommodate the new observations, and the Director will weigh the consequences of inserting the new projects against the scientific promise of the displaced observations. Even if a DDT program is accepted, observing time is not guaranteed to be performed because the full impact is not known until Phase II and preliminary flight planning is complete.

Because DDT projects generally address time-critical phenomena that are of high interest to the community, there will not be an extended proprietary period where the data can only be accessed by the proposing team. For comparison, for observations proposed through the annual Calls, there is a one year proprietary period. For DDT, in contrast, there shall be no proprietary period for accessing the data, unless such right is specifically granted for that project by the Director; in the case where a proprietary period is granted it is not expected to be longer than 3 months.

When developing an observing plan that requires a rapid response, keep the following issues in mind and include relevant justification in your proposal. A turnaround time as fast as 10 days is possible, and sometimes an even more rapid turnaround can be accomplished. For a highly-motivated observation, the single most important factor in determining the speed and complexity of observatory response is the state and availability of the required scientific instrumentation (SI). If the new observation uses the SI already on the observatory, the fastest and easiest response is possible. Proposers are welcome to request specific observatory schedule information (including planned observing campaigns for the near future) through the Helpdesk. Facility science instruments (FORCAST, FIFI-LS, and HAWC+) are at the disposal of the science center and should generally be ready for usage. Principal Investigator instruments (GREAT and EXES) may be requested as part of a DDT proposal, but their availability cannot be guaranteed because they require the SI team for operations. It is not required to work with the PI team when developing a proposal utilizing their instrument, but such contact is recommended in particular for urgent observations. The most disruptive observing proposals to the already-accepted observing program and staff schedules are those that require urgent and/or coordinated observations with multiple instruments. Be sure to justify such observing proposals carefully.

Approved SOFIA DDT Programs

Questions about the proposal or the process should be addressed to the Help Desk.

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