The Space Telescope Science Institute (STScI) has issued a formal call for community white papers describing ambitious science programmes that would use the James Webb Space Telescope (JWST) across multiple cycles and require telescope time far in excess of the typical large programme.
What STScI is asking for
The institute is inviting ideas for Multi‑Cycle Treasury (MCT) programmes that address any science topic but share one requirement: they should need amounts of JWST time larger than what is normally granted through the regular Time Allocation Committee process, which the call identifies as about 300 hours. The deadline for community white papers is 11:59 p.m. ET on Wednesday, Nov. 4, 2026.
STScI says the move is motivated by JWST's continuing high performance as it enters its fifth year of regular science operations and the telescope's capacity to enable transformative investigations ranging from small bodies in the Solar System to cosmology. The agency is seeking projects that can take advantage of "unprecedented data quality" and the observatory's anticipated capabilities over coming years.
"White Papers should be limited to no more than 5 pages"
Opportunities and constraints for the community
The MCT concept is intended to encourage science that cannot be accomplished within the time caps typical of regular calls. STScI specifically asks for proposals that would need allocations significantly exceeding ~300 hours, and it also invites white papers outlining concerns about establishing an MCT programme.
White papers should describe compelling science cases, explain why the project requires a multi‑cycle approach or exceptionally large time investment, and justify the anticipated scientific return. STScI provides supporting material including a JWST Pocket Guide and documentation of new modes and instrument updates for Cycle 6 to help teams assess feasibility.
Practical details
Submissions must follow the institute's guidance and be filed through the specified online form. The call page and submission links provide technical details and additional resources to help proposers plan programmes that could span more than one observing cycle.
| Item | Detail |
|---|---|
| Deadline (ET) | Nov. 4, 2026, 11:59 p.m. |
| Page limit | 5 pages (white paper) |
| Typical large programme cap | ~300 hours |
Context and potential consequences
The proposal window comes as JWST moves beyond its initial demonstration and early science phases into sustained operations where both the telescope and instruments are delivering high‑quality data. By explicitly soliciting MCT concepts, STScI is signalling an openness to rethinking how very large, coordinated JWST programmes might be supported — potentially similar in ambition to legacy or treasury programmes from previous missions.
For researchers, the new call could unlock the ability to pursue extended, homogeneous surveys, deep time‑domain studies, or multi‑epoch programmes that require continuity over several cycles. But the move will also raise strategic questions about allocation priorities: how much of JWST's finite observing time should be reserved for a few very large programmes versus a larger number of smaller, investigator‑led proposals?
- Potential benefits: enable transformational, community‑wide datasets; reduce duplication; build legacy archives.
- Potential concerns: concentrate precious observing time in a few teams; raise access and equity issues for smaller groups.
- Submission constraints: white papers limited to five pages; proposers must justify need for time beyond typical caps.
STScI also welcomes white papers that articulate concerns about the MCT framework, giving the community a channel to influence design and governance before any formal MCT programmes are instituted.
The call includes links to a detailed JDocs page, an online submission form, and supplemental material such as the JWST Pocket Guide and Cycle 6 instrument updates to help teams craft technically feasible proposals.
As the community prepares responses, the call marks a notable moment in JWST's lifecycle — one that could shape the observatory's scientific legacy and the distribution of its time for years to come.
