JWST Director's Discretionary (DD) time proposals are discussed in this page, including the circumstances under which they are used and how to submit them during JWST Cycle 5. More information about past and present opportunities is available at James Webb Space Telescope Director's Discretionary Time.

See also: JWST Director's Discretionary (DD) Time Proposals, JWST Call for Proposals for Cycle 5

DD proposals may be submitted at any time, via APT, and correspond to the JWST observing cycle in which they are submitted.

The current JWST observing cycle is Cycle 5 (July 1, 2026–June 30, 2027). Proposers should therefore refer to the JWST Call for Proposals for Cycle 5 for requirements and policies. Funding is dependent on the JWST Cycle 5 budget.

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General DD requirements

All DD proposals, regardless of type, must:

• be scientifically urgent, i.e., providing timely follow-up of new discoveries that provide a critical link in the understanding of phenomena that would have significant impact on the broader field;
• be sufficiently detailed for adequate evaluation. The required level of detail is the same as that required for proposals submitted for the regular observing cycles, as described in the JWST Call for Proposals for Cycle 5. Among other things:
  • both the proposed observations and the use of DD time must be explicitly justified;
  • there must be an adequate description of how the proposed observations relate to the current state of knowledge;
  • the proposed observations must be described in sufficient detail to allow technical evaluation;
  • the APT file must be telescope-ready.

Time Critical and Discovery DDs have additional requirements, described below and in the Rubric.

DD proposals may not:

• be re-submitted previously-rejected GO or DD proposals, unless there has been a substantive change in the basis for the proposal (e.g., new observations or theoretical advances). 
• be Targets of Opportunity (ToO). This includes requests to reserve ToO targets that have not yet been discovered.

• be Pure Parallel or Survey programs. These programs are suited to large pools of targets where the science goals can be achieved regardless of the exact number of targets observed and the specific targets observed and are, thus, incompatible with the scope and purpose of the DD opportunity.

• be preparation for future observing cycles (this is typically an insufficient justification for DD time).

Scheduling requirements and execution timeline

All DD proposals undergo extensive review before they are potentially executed, including external peer review and internal instrument review. When considering scheduling feasibility of the requested observations, proposal PIs must factor in time to complete each component of the review, as they impact the timeline for implementation. Once a proposal is approved, any subsequent requests for changes may jeopardize the execution of the program and will be accepted only under highly exceptional circumstances. More details on the review timeline are given below; refer also to the JWST Observation Review and Implementation page.

Depending on the minimum required turn-around time, DD activations may be Non-disruptive, Disruptive, or Ultra-disruptive; they follow the same definitions as ToOs.

When considering whether a DD proposal is Non-disruptive, Disruptive, or Ultra-disruptive, PIs should factor in the time to complete an expedited review: a minimum of 5 days (5-7 days for proposals submitted late in the week). The typical turnaround time for Non-disruptive DD proposal reviews is ~3 weeks; Discovery DDs may take longer (as by definition they are not time critical). 

*NIRSpec MOS programs must be finalized at least 8 weeks before execution. Consequently, NIRSpec MOS mode is not available for (Ultra-)Disruptive DD programs.

†Ultra-disruptive DD activations are very hard to schedule and hence are very rare. Requests for Ultra-disruptive DD activations require robust and thorough justification.

Proposal Resubmission

Rejected GO and DD proposals may not be re-submitted unless:

• Proposers have received explicit guidance from STScI, or

• There has been a substantive change in the basis for the proposal, e.g., new observations or theoretical advances that have had a major impact on the understanding of the object or phenomena under study.

Funding

Subject to availability of funds from NASA, STScI will provide financial support for U.S. PIs and Co-Is of approved DD programs.

The pool of funding is limited. Once funding for the Cycle is exhausted, no further funding will be allocated.

See the JWST Grant Funding and Budget Submissions - Cycle 5 page for more information.

Types of DD programs

Time Critical DD proposals

Time Critical DD time proposals are suitable for observations that could not have been requested in a previous observing cycle and cannot wait for the next standard observing cycle.

Examples of potentially appropriate Time Critical DD time requests include:

• Follow-up of newly-discovered unexpected transient phenomena;
• When developments since the last proposal cycle make a time critical observation necessary. 

Examples of observations that are not suitable for Time Critical DD time requests include:

• Observations that could plausibly have been proposed in the most recent regular proposal cycle, possibly as a target of opportunity proposal;
• Observations that could wait until the next proposal cycle with no significant reduction in the expected scientific return.

Time Critical DD time proposals should be small, typically <15 hours in size. Proposals requesting significantly more than 15 hours are generally better suited for the standard observing cycle and its TAC review process.

Discovery DD proposals

Discovery DD time proposals are suitable for observations of compelling scientific urgency that significantly accelerate scientific discovery.

Examples of potentially appropriate Discovery DD time requests include:

• The timely follow-up of new discoveries that provide a critical link in the understanding of phenomena that would have significant impact on the broader field.

Examples of observations that are not suitable for Discovery DD time requests include:

• Small-scale pilot or test observations;
• Observations that are a subset of larger observing programs planned for future cycles; 
• Observations that are requested in order to prepare for more/follow-up observations in future cycles;
• Observations that do not have significantly compelling scientific urgency, and would therefore be more appropriately evaluated by the TAC review process during a standard observing cycle.

Discovery DD time proposals should be small, typically <10 hours in size. Unless the science is highly compelling, proposals requesting significantly more than 10 hours are generally better suited for the standard observing cycle and its TAC review process.

Discovery DD time proposals that are submitted not long after standard cycle proposal deadlines must have indisputable evidence for why they could not have been submitted during the standard cycle; otherwise, they will be disqualified. If such proposals are determined to be valid Discovery DDs, then the proposals might be evaluated by members of the standard TAC. They are also subject to longer periods of external peer review.

Joint DD proposals

Joint JWST-HST DD proposals are permitted, for either Time Critical or Discovery DDs. All Joint JWST-HST proposals should be submitted using the JWST APT. Joint DD proposals with other facilities are not permitted.

JWST DD proposals to complement data obtained during the standard HST (or other Partner Observatory) Call for Proposals must compellingly justify why the JWST data were not originally proposed for as part of a Joint Observing Proposal and hence why they could only be obtained as a JWST DD proposal.

Preparing your DD proposal

Filling out the APT proposal form

Proposers must use the Astronomer's Proposal Tool (APT) to submit their DD programs. Make sure to mark the DD checkbox and to select the DD type from the drop-down menu. To download and install APT, go to the APT webpage. For help on using APT to prepare and submit a JWST program, please refer to the Getting Started with Planning JWST Observations article. You will be providing all necessary information (including all necessary observing parameters, special requirements, and PDF attachment) via APT.

DD proposals must be submitted in, and will be reviewed in, an anonymous format. The review process is similar to that used in the JWST Anonymous Proposal Reviews - Cycle 5, except the review of the team expertise will be done internally by the Science Policy Division. Please fill out the "Team Expertise and Background" section of the APT Proposal Information Form, but it will not be shared with the reviewers.

Preparing the proposal PDF attachment

The PDF attachment for DD proposals is uploaded via APT.

Templates

Templates for the PDF attachment can be found on the JWST Preparation of the PDF Attachment - Cycle 5 page (mirrored below). 

Page limits

The PDF attachment should follow the page limits for proposals of the same-sized GO proposal category, as given on the JWST Preparation of the PDF Attachment - Cycle 5 page (mirrored below).

Sections

All DD proposals must include the following sections:

• "Rationale for DD program" (described below),
• "Scientific Justification,"
• "Technical Justification," and
• "Special Requirements" (described below).

Optional (if required) sections include:

• "Justify Coordinated Parallel Observations,"
• "Justify Coordinated Observations with Other Facilities" (only Joint JWST-HST DD programs are permitted), and
• "Justify Duplications." 

Rationale for DD program

This section of the proposal should explain:

• the science impact of the observations, both in advancement of the field and in overall importance to astronomy;
• why the observations are timely and cannot wait until the next cycle;
• why they could not have been proposed at the previous cycle call.

Special Requirements

In addition to any necessary special requirements described in JWST Preparation of the PDF Attachment - Cycle 5, DD proposals must include:

• an explicit statement on when the observations have to be executed;
• whether the observations are Non-disruptive, Disruptive, or Ultra-disruptive, as described above.

How your DD proposal is evaluated

In-house proposal compliance and urgency review

Upon completion of your DD submission, your program will be transferred to the STScI Science Policy Division (SPD) for processing by our DD team.

The DD team will first determine whether the proposal complies with DD policies, including checking for DD justifications and timing requirements, and ensuring there are no Dual Anonymous Peer Review, page limit, or template formatting violations. Re-submissions of previously-rejected proposals will be rejected automatically.

Next, the DD team will undertake an initial review of the proposal against the general DD criteria and will perform a scientific urgency assessment. Proposals that do not meet those criteria or are deemed not scientifically urgent will not be distributed for further review; the Principal Investigator will be informed of that decision, and is free to submit the proposal at the next standard cycle deadline.

External scientific review

DD proposals passing the initial in-house compliance and urgency reviews are sent out for scientific review by members of the community. DD proposals are reviewed in an anonymous process, similar to that described in the JWST Anonymous Proposal Reviews - Cycle 5.

External reviewers summarize the strengths and weaknesses of the proposal and grade according to the DD evaluation rubric provided below.

Ideally, each proposal will receive four reviews; we will proceed with fewer reviews in exceptionally time-sensitive cases where reviewers are non-responsive or challenging to recruit. 

DD proposal rubric

All DD time proposals will be evaluated through external peer review according to the following Rubric:

^*Numerical grades correspond to: (1) Excellent, (2) Very Good, (3) Good, (4) Fair, (5) Poor.

Help and more information

If you run into problems submitting a DD request, contact the STScI JWST Help Desk for investigation and resolution.

Please refer to James Webb Space Telescope Director's Discretionary Time for more information regarding DD proposals.