The requirements for JWST Cycle 3 Guaranteed Time Observations (GTO) proposals are described, including eligibility and observing restrictions.

The general science policies established for Cycle 1 and 2 proposals also apply to Cycle 3 proposals.

Cycle 3 GTO proposals may not include scientifically-unjustified duplications of observations planned as part of the Cycles 1 or 2 GTO programs or TAC-accepted Cycles 1 or 2 GO programs, Early Release Observations (EROs), ERS programs, and other accepted Director’s Discretionary Time (DDT) programs. The MAST Discovery Portal provides a standard interface for JWST Observation duplication checking against scheduled and completed Cycles 1 and 2 GTO, GO, DD-ERS and DDT programs. Duplications between GTO proposals will be identified and conflicts will be resolved following the process outlined in NASA-SMD Policy 11. All conflicts will be resolved prior to the release of the Cycle 3 GO Call for Proposals. The Cycle 2 GO results will be announced on May 10, 2023.

Cycle 3 GTO proposals must specify detailed observations for each science target included in the science programs. As in Cycles 1 and 2, individual GTO scientists and members of GTO science teams may each submit multiple Cycle 3 GTO APT proposals; the time charged will be the sum of the total time (including overheads) requested by the individual APT proposals assigned to each GTO. If appropriate, the total time charged may be adjusted to incorporate revisions in the overhead rates. GTOs may look up the available wall-clock time remaining in their allocations on the Guaranteed Time Observer (GTO) Allocations page.

The final list of Cycle 3 GTO JWST observations will be made publicly available in conjunction with the GO Cycle 3 Call for Proposals. All observations included in the Cycle 1, 2, & 3 GTO APT proposal submissions will be protected from scientifically-unjustified duplication by Cycle 3 GO programs.

Cycle 3 is the last cycle in which GTOs may submit GTO proposals.

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