Director's Discretionary (DD) Time Proposals

Up to 10% of the available JWST observing time in a given cycle may be reserved for Director’s Discretionary (DD) allocation. In Cycle 1, a substantial fraction of that time has been invested in the Director's Discretionary Early Release Science program. Scientists wishing to request DD time can do so at any time post-launch.

Observations obtained as part of a DD Program generally do not have an exclusive access period, and are made available immediately to the astronomical community. However, DD proposers may request and justify such periods in their proposals. Upon receipt of a DD Proposal, the STScI Director will usually seek advice on the scientific merit and technical feasibility of the proposal from STScI staff and external specialists. A proposal for DD time might be appropriate in cases where an unexpected transient phenomenon occurs or when developments since the last proposal cycle make a time-critical observation necessary.

DD Proposals for timely follow-up of new discoveries will also be considered even if the astrophysics of the phenomena do not require such rapid follow-up. In such cases, the proposers must demonstrate that the observations will provide a critical link in the understanding of the phenomena and that carrying them out quickly is particularly important for planning future observations with major facilities. They should then also indicate their plans for quickly making the scientific community aware of their discoveries, to enable subsequent wider community follow-up.

DD observations should not generally be requested if any of the following is true:

  • The observations could plausibly have been proposed in the most recent regular proposal cycle, possibly as a Target-of-Opportunity Proposal.
  • The observations were proposed in a recent regular proposal cycle, and were rejected.
  • The proposed observations could wait until the next proposal cycle with no significant reduction in the expected scientific return.

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


Next: JWST Cycle 1 Observation Types and Restrictions