Small, Medium, Large, and Treasury GO Proposals may request JWST observing time in more than one cycle if a clear scientific case can be made. Long-Term Proposals must be limited to cases where long-baseline, multi-epoch observations are clearly required to achieve the scientific goals. Long-Term Proposals require a long time baseline, but not necessarily a large number of JWST hours, to achieve their science goals. Examples include astrometric observations or long-term monitoring of variable stars or active galactic nuclei. 

Proposers may request time in up to three cycles (1, 2, and 3). Long-term Proposals should describe the entire requested program and provide a cycle-by-cycle breakdown of the number of hours requested. The Cycle 1 review panels and TAC will only be able to award a limited amount of time in future cycles, so a detailed scientific justification for allocating time beyond Cycle 1 must be presented. Scheduling concerns are not a sufficient justification. The sum of all hours requested in Cycles 1, 2, and 3 determines whether a Long-Term Proposal is Small, Medium, or Large, with the appropriate exclusive access periods applied (12 months for Small and Medium, and 0 months for Large). Target-of-Opportunity Proposals are eligible to be Long-Term for rare phenomena if certain conditions are met (see JWST Cycle 1 Observation Types and Restrictions). GOs with approved Long-Term Proposals are not required to submit continuation proposals for subsequent cycles.

Next: Archival (AR) Proposals