This page describes JWST proposal categories including General Observer (GO), Survey, and Archival Research (AR) proposals. General Observer proposals may be submitted for any amount of observing time on JWST. Survey proposals consist of short-duration observations of a specified large list of targets; there is no completeness guarantee. Proposals may also be submitted to financially support Archival Research for the analysis of archival JWST data, to develop data science software to benefit the community of JWST users, or to financially support theoretical research in support of JWST observational programs. 

Overview of proposal categories

New JWST observations can be requested with General Observer (GO) Proposals, Survey Programs, or through Director's Discretionary (DD) Time Proposals:

• GO proposal categories include Very Small, Small, Medium, and Large. GO proposals may include additional GO flags to highlight particular attributes of the program, including Target of Opportunity (ToO), Pure Parallel, Calibration GO, Future Cycles GO, Treasury GO, Combined GO+AR, or Joint Observing; these flags come with additional requirements.
• Survey programs consist of similar, relatively short observations of targets drawn from a large sample; unlike GO programs, Survey programs have no guaranteed completion fraction.
• Investigators may submit requests for DD programs at any time for unanticipated and scientifically compelling astronomical observations.

Funding for JWST-related projects that do not require new JWST observations can be requested with an Archival Research (AR) Proposal. An AR proposal can be a Regular or Legacy AR depending on the scope and/or funding request. AR proposals may include additional AR flags to highlight particular attributes of the program, including Calibration AR, AR Theory, AR Cloud Computing, or AR Data Science Software; these flags come with additional requirements.

Different proposal types and sizes have different page limit requirements for the PDF attachment. Proposers should carefully check the page limits for their proposal category. Proposals that exceed the page limits for their size category will be subject to disqualification in the review process.

All GO, Survey, and AR proposals are peer-reviewed by a Telescope Allocation Committee (TAC), as described in JWST Proposal Selection Procedures. 

General Observer (GO) Proposals

A GO Proposal may be submitted for any amount of observing time. GO Proposals are classified as Very Small (≤ 20 hours), Small (> 20 and ≤ 50 hours), Medium (> 50 and ≤ 130 hours) and Large (> 130 hours). The classification into these categories is based on total charged time, including overheads.

JWST will be offering 8,000 hours for observations in Cycle 5. Based on the Cycle 4 proportional allocation, we anticipate that the distribution of hours among proposal size categories will be approximately 1,300 hours for Very Small, 2,800 hours for Small, 2,500 hours for Medium, and 1,400 hours for Large and Treasury programs. The exact allocation to each size category is subject to adjustment based on proposal pressure. 

There are additional (optional) "flags" that may apply to GO proposals of any size. Please note that each flag has additional requirements that must be satisfied:

• Target of Opportunity (ToO) Proposals are for observations of an event that may occur at an unknown time (see also the ToO Observations section of JWST Observation Types).
• Pure Parallel Programs utilize instruments other than the primary instrument on observations from unrelated proposals (see also the Pure Parallel Observations section of JWST Observation Types).
• Calibration GO Proposals provide calibrations for non-standard instrumentation modes.
• Proposers can request observing time in future cycles as a Future Cycles GO Proposal when this is scientifically justified. The proposal's total time, and hence its size category, will be determined from the sum total of time for all cycles in the request.
• The category of Treasury GO Proposals is designed to stimulate certain types of ambitious and innovative proposals. These typically have a significant legacy value by making available  public high-level data products or software tools and may be any size.
• Combined GO+Archival (AR) programs are available when substantial effort (>10%) will be devoted analyzing JWST archival data and where new observations are still required to address a scientific goal.
• There are opportunities to apply for Joint Observing Programs with other specific observatories to obtain multi-wavelength data.

The "Scientific Justification" section of the PDF attachment should present a balanced discussion of background information, the program's goals, its significance to astronomy in general, and its importance to the specific sub-field of astronomy it addresses. All GO Proposals must include a "Technical Justification" section in the PDF attachment.

GO proposals of different sizes have different page limit requirements for the PDF attachment.

Very Small GO proposals will be reviewed by the External panels. Small and Medium GO proposals and all ToO Observations, regardless of size, will be reviewed by the Discussion panels. The Executive Committee (EC) will review Large GO proposals and all Treasury GO programs, regardless of size. Further details on the review process are given in JWST Proposal Selection Procedures.

Proposers should note that all JWST observations are accepted with the understanding that the timescale on which the observations will actually be obtained will depend on scheduling opportunities and demands on JWST resources. Programs, particularly those with significant scheduling constraints, may require execution over a period that may extend into future cycles.

In general, proposals are either accepted or rejected in their entirety. Accordingly, proposers are urged to request the actual number of hours required to achieve the proposal science goals.

Additional components of a GO proposal may include:

• Laboratory astrophysics relevant to JWST observations.
• Ground-based observations that complement JWST observations. Note that these observations are generally obtained independently, as STScI does not award time on ground-based facilities except for Joint Observing programs awarded as part of this Call.
• A citizen science component in support of the program science goals. NASA document SPD-33 provides guidelines on citizen science projects.

Note: Funded support for associated ground-based observations, laboratory astrophysics, and citizen science must be compliant with the  STScI General Grant Provisions (GGP) and is limited to no more than 10% of the total budget. These components must be specified and justified in the original science proposal and may not be added subsequent to acceptance.

Very Small GO Proposals

Very Small GO Proposals are those that request less than or equal to 20 hours of total time. Very Small GO proposals will be reviewed by the External panels instead of the discussion-based (i.e., face-to-face) review panels; further details on the review process are given in JWST Proposal Selection Procedures. The default Exclusive Access Period for Very Small proposals is 12 months.

Small GO Proposals

Small GO Proposals are those that request above 20 hours but less than or equal to 50 hours of total time. Small GO proposals will be reviewed by the Discussion panels; further details on the review process are given in JWST Proposal Selection Procedures. The default Exclusive Access Period for Small proposals is 12 months.

Medium GO Proposals

Medium GO Proposals are those that request above 50 hours but less than or equal to 130 hours of total time. The Medium Proposal category exists to ensure that compelling science programs that demand a medium-size time request have appropriate opportunities for success. Medium GO proposals will be reviewed by the Discussion panels; further details on the review process are given in JWST Proposal Selection Procedures. The default Exclusive Access Period for Medium proposals is 12 months. 

Large GO Proposals

Large Proposals are those that request more than 130 hours of total time. These programs should lead to a clear advance in our understanding in an important area of astronomy. They must use the unique capabilities of JWST to address scientific questions in a comprehensive approach that is not possible in smaller time allocations. Selection of a Large Proposal for implementation does not rule out acceptance of Small or Medium Proposals to do similar science, and vice versa.  But, as with all programs, target duplication and overall program balance will be considered. Large GO proposals will be evaluated by the Executive Committee; further details on the review process are given in JWST Proposal Selection Procedures.

Data taken for Large Proposals will, by default, have no Exclusive Access Period. Proposals may request an Exclusive Access Period; that request must be justified in the "Special Requirements" section of the proposal and will be subject to TAC review.

Additional GO flags (optional)

GO Proposals of any size can have additional "flags" to highlight particular features of those programs. These additional flags are optional (not every GO program will need one). Proposals may include multiple flags (though some specific combinations are not allowed). These flags include Target of Opportunity (ToO), Pure Parallel, Calibration GO, Future Cycles GO, Treasury GO, Combined GO+AR, and Joint Observing. Each flag has additional requirements that need to be met. These flags correspond to selectable options and expandable menus on the Proposal Information form in APT.

Target of Opportunity (ToO) Proposals

Proposers should consult the description of ToO Observations under JWST Observation Types.

ToO observations cannot be included in Pure Parallel programs. Disruptive or Ultra-disruptive ToO observations cannot request Future Cycles observations.

Investigators submitting ToO Proposals must fill out the "Number of Target of Opportunity Activations" expandable menu on the APT Proposal Information form.

The JWST GO hours request determines whether the proposal is Very Small, Small, Medium, or Large. Non-disruptive ToO Proposals are eligible to be Future Cycles proposals, in which case the sum of all hours requested, including those in the future cycles, determines the size category. All ToO Proposals are evaluated by the Discussion panels, regardless of size, as detailed in the JWST Proposal Selection Procedures. ToO Proposals have the same Exclusive Access Period and should follow the page limit requirements as for regular GO proposals of the same size category.

Pure Parallel Programs

Proposers should consult the description of Pure Parallel Observations under JWST Observation Types.

Pure Parallel programs may not include ToO or Future Cycles components.

Proposers should address the value of the data products that will be generated by the Pure Parallel program to the astronomical community in the "Scientific Justification" section of the PDF attachment.

Investigators submitting Pure Parallel Proposals must select the "Pure Parallel Proposal" flag on the APT Proposal Information form.

The JWST GO hours request determines whether the proposal is Very Small, Small, Medium, or Large. Pure Parallel Proposals have the same Exclusive Access Period and should follow the page limit requirements as for regular GO proposals of the same size category. Pure Parallel Programs of any size will be evaluated by the Executive Committee; further details on the review process are given in JWST Proposal Selection Procedures.

Calibration GO Proposals

JWST is a complex observatory, with many possible instrument configurations. Calibrations and calibration software are maintained by STScI for the most important and most used configurations. However, STScI does not have the resources to calibrate fully all potential capabilities of all instruments. Additionally, the astronomical community has expressed interest in receiving support to perform calibrations for certain uncalibrated or poorly calibrated modes, or to develop specialized software for certain JWST calibrations. In recognition of this, STScI is encouraging users to submit Calibration Proposals, which aim to fill gaps in the calibration of JWST and its instruments.

Calibration Proposals should not be linked to a specific science program, but should provide a calibration or calibration software that can be used by the community for existing or future programs. A specific science program that has special calibration requirements is not a Calibration Proposal; such a proposal should be submitted as a normal GO Proposal and the necessary calibration observations should be included in the science program.

Calibration GO Proposals will be reviewed internally at STScI after the proposal deadline (and before the TAC Review Meeting). The internal review will provide the TAC with an assessment of the feasibility of the proposal, how the proposal complements/extends the existing calibration program, and the type of science impacted by the proposed calibrations. Proposers should summarize the relevance and overall scientific utility of the calibration techniques and products described in their proposal. The "Scientific Justification" should describe what science will be enabled by the successful completion of the program, and how the currently supported core capabilities, their calibrations, and the existing data processing are insufficient to meet the requirements of this type of science. Calibration GO Proposals should include both a "Technical Justification" (describing the observations to be taken) and an "Analysis Plan" in the PDF attachment. The "Analysis Plan" should discuss what documentation, and data products, and/or software will be made available to STScI to support future observing programs. Proposers should explain how their programs complement ongoing calibration efforts by the STScI instrument groups. They should contact the relevant instrument groups to ensure that efforts are not duplicated, and if they are, justify why the duplications are necessary.

Successful proposers will be required to deliver documentation, data products, and/or software to STScI to be made available to the community to support future observing programs or archival research. Funding is available to support Calibration GO Proposals in the same manner as for normal science programs, with the following exception: Scientists affiliated with STScI are not eligible for any funding to support their role (as PI, Co-PI, or Co-I) in a Calibration Proposal.

Investigators interested in submitting a Calibration GO Proposal are encouraged to study the JWST User Documentation to determine the level at which STScI provides calibration and characterization. The data obtained for a Calibration GO Proposal will nominally have no Exclusive Access Period, as is the case for regular calibration observations. Proposers may request an Exclusive Access Period (which must be explained in the "Special Requirements" section of the PDF attachment), but such a request will be subject to panel and TAC review and will only be granted in exceptional circumstances. 

Investigators submitting Calibration GO Proposals must select the "Calibration" flag on the APT Proposal Information form.

The JWST GO hours request determines whether the proposal is Very Small, Small, Medium, or Large. Calibration GO Proposals are subject to the same review process and should follow the page limit requirements as for regular GO proposals of the same size category.

Future Cycles GO Proposals

GO proposals of any size may request JWST observing time in more than one cycle if a clear scientific case can be made. Future Cycles Proposals must be limited to cases where long-baseline, multi-epoch observations are clearly required to achieve the scientific goals. Future Cycles 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 (5, 6, and 7), or in up to five observing cycles under the Long-Term Monitoring (LTM) Initiative. Future Cycles Proposals should describe the entire requested program and provide a cycle-by-cycle breakdown of the number of hours requested in the PDF Attachment. The 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 5 must be presented. Scheduling concerns are not a sufficient justification. The cycle-by-cycle breakdown needs to be entered in the APT Proposal Information form using the "Future Cycles” menu. If this field is not marked and filled out, the Future Cycles request might not be met, even if it is described in the proposal. The APT file should only contain the observations corresponding to the current cycle. APT files for time awarded in future cycles will be requested at a later time.

Approved Future Cycles GO Proposals are not required to submit continuation proposals for subsequent cycles.

Non-disruptive ToO observations are eligible to be Future Cycles proposals; Disruptive or Ultra-disruptive ToO observations cannot be requested in Future Cycles (see JWST Observation Types). Future Cycles cannot be requested for Pure Parallel programs.

Investigators submitting Future Cycles Proposals must fill out the "Future Cycles" expandable menu on the APT Proposal Information form. Investigators participating in the LTM Initiative must select the "Long Term Monitoring" flag on the APT Proposal Information form. Once checked, observations for two future cycles beyond the default 3-cycle limit will be able to be requested (though not required).

The sum of all hours requested in all future cycles determines whether a Future Cycles Proposal is Very Small, Small, Medium, or Large. Future Cycles GO Proposals have the same Exclusive Access Period, are subject to the same review process, and should follow the page limit requirements as for regular GO proposals of the same size category. 

Treasury GO Proposals

Treasury Proposals are those designed to create JWST datasets of lasting scientific value. A Treasury Program is defined by the following characteristics:

• The program should focus on the potential to solve multiple scientific problems with a single, coherent dataset. It should enable a variety of compelling scientific investigations.
• The program should produce data products that are processed or calibrated significantly beyond the capabilities of the JWST Calibration Pipeline to maximize the scientific impact of the program. Examples include tiled images, multi-band object catalogs, or coordinated observations on other facilities (for which some funding can be provided). Funding for the proposed data products will depend on their timely availability. They should be delivered to STScI in suitable digital formats for dissemination via the Mikulski Archive for Space Telescopes (MAST).
• Data taken under a Treasury Program will usually have no Exclusive Access Period, although a brief Exclusive Access Period may be requested if it will enhance the public data value; that request must be justified in the "Special Requirements" section of the PDF attachment and will be subject to TAC review. 

The following additional characteristics are particularly encouraged:

• Development of new techniques for data reduction or analysis.
• Creation and dissemination of tools (software, Web interfaces, models, etc.), beyond what is offered to the community by STScI, for the scientific community to work with the data products.

The emphasis will be on observations whose value is maximal if taken in the current cycle. However, Treasury Proposals may request observing time to be distributed in future cycles if scientifically required (similar to Future Cycles GO Proposals). 

The "Scientific Justification" section of the proposal's PDF attachment should include a description of the scientific investigations that will be enabled by the final data products, their importance, and value to the astronomical community. The "Technical Justification" section should not only include a detailed rationale of the observations, but also plans for data analysis and a description of how the data products will be made available to STScI and the community, the method of dissemination, and a realistic time line. 

Investigators submitting Treasury Proposals must select the "Treasury" flag on the APT Proposal Information form and include additional technical details on the scheduling aspects of their program in the “Proposal Observing Description” section in APT.

Treasury programs can be Very Small, Small, Medium, or Large proposals. Treasury GO proposals of any size will be evaluated by the Executive Committee; further details on the review process are given in JWST Proposal Selection Procedures. Because of their scale, Treasury GO programs of any size have increased page limits, as detailed in JWST Preparation of the PDF Attachment.

Combined GO+AR Programs

We are offering the Combined GO+AR option for research programs where substantial effort (>10%) will be devoted analyzing JWST archival data and where new observations are still required to address a scientific goal. The PDF attachment of GO+AR proposals must include a "Technical Justification" for the new data and an "Analysis Plan" for the archival data.

Programs that require funding for Archival Research alongside new observations should be submitted as a single GO Proposal (rather than separate GO and AR proposal submissions). The Combined GO+AR category is applicable when the archival component comprises >10% of the total effort of the research program. Programs with a less significant archival component should be submitted as a regular GO program. In either case, the GO and archival science must be clearly described and justified.

Investigators submitting Combined GO+AR Proposals must select the "GO-Archival" flag on the APT Proposal Information form.

Proposers should also be familiar with the requirements for AR Proposals. They can select additional GO or AR flags as appropriate.

The GO time request determines if a Combined GO+AR proposal is Very Small, Small, Medium, or Large. Combined GO+AR proposals have the same Exclusive Access Period and are subject to the same review process as for regular GO proposals of the same size category. They should follow the page limit requirements as for regular GO proposals of the same size category, with the exception of Very Small and Small Combined GO+AR proposals which are allowed an additional page to accommodate the "Technical Justification" and "Analysis Plan." Please consult JWST Preparation of the PDF Attachment for details.

Joint Observing Programs (Multi-Observatory)

STScI has reached agreements with several other observing facilities (ALMA, Chandra, HST, NASA Keck, NOIRLab, NRAO, TESS, XMM-Newton) to award time for joint programs in which JWST science is the prime science, but multi-wavelength observations from another ancillary observatory are critical for the science goals of the proposal. Joint JWST programs with more than one observatory are allowed. Joint proposals aim to remove double jeopardy in the review process (i.e. being subject to two independent review processes).

Joint Programs should be submitted to only one facility, not to both observatories:

• For JWST-ALMA, JWST-HST, and JWST-NRAO Joint Proposals, the proposal should be submitted to the observatory that requires the larger time allocation (where 1 JWST hour of charged time is equivalent to 1 HST orbit).
• For JWST-Chandra and JWST-XMM-Newton Joint Proposals, the proposal should be submitted to the facility that represents the prime science.
• For JWST-NASA Keck, JWST-NOIRLab, and JWST-TESS Joint Proposals, the proposals should be submitted as a response to the JWST Call. 

Proposers are responsible for fulfilling all necessary requirements requested by the partner observatories. This includes noting what information needs to be submitted, meeting the deadlines for submitting that information, and ensuring that contact details are up to date. 

Unless otherwise stated in the proposal, it is assumed that there is no requirement on the relative timing of the JWST and Partner Observatory observations. A request for contemporaneous or near-simultaneous observations can be made if scientifically justified and technically feasible, but there is no guarantee that these can/will be executed.

The only criterion above and beyond the usual review criteria is that both sets of data are required to meet the primary science goals.

Investigators submitting Joint Observing Proposals must select the "Multi-Observatory" flag on the APT Proposal Information form. Additionally, they must fill out the "Multi-Observatory Information" section.

Joint Observing programs can be Very Small, Small, Medium, or Large programs; proposers should determine the size category based on the JWST hours request. Joint Observing programs have the same Exclusive Access Period, are subject to the same review process, and should follow the page limit requirements as for regular GO proposals of the same size category. Proposers should take care to include any partner-observatory specific justifications in the "Justify Coordinated Observations with Other Facilities" section of the PDF attachment.

The information below corresponds to Joint proposals where JWST is primary and that are evaluated by the JWST TAC. Proposals where JWST is secondary should be submitted in response to the Partner Observatory Call for Proposals (see Submission Process for Joint JWST Proposals where the Partner Observatory is Prime). Joint Proposers should always follow the Partner Observatory documentation to avoid inconsistencies between the initial technical justification, including requested time, and what is actually required. Otherwise the proposal, including the JWST part, may be deemed unfeasible. 

Joint JWST-ALMA Observing Proposals

By agreement with Joint ALMA Observatory (JAO), the JWST Telescope Allocation Committee (TAC) will award up to 115 hours of ALMA time on each of the ALMA arrays (12-m, 7-m, and Total Power) to highly ranked proposals that require both JWST and ALMA observations. Similarly, the JAO will be able to award up to 115 hours of JWST time to highly rated proposals awarded ALMA time in its TAC process. The only criterion above and beyond the usual review criteria is that the project must be fundamentally of a multi-wavelength nature, and that both sets of data are required to meet the science goals. ALMA time will only be awarded in conjunction with new JWST observations (and should not be proposed for in conjunction with an AR or Theory Proposal).

Unless otherwise stated in the proposal, it is assumed that there is no requirement on the relative timing of the JWST and ALMA observations. A request for contemporaneous or near-simultaneous observations can be made if scientifically justified and technically feasible but there is no guarantee that these can/will be executed.

Proposals for combined JWST and ALMA observations should be submitted to the observatory with the larger time request (not to both observatories). STScI reserves the right to disallow JWST observations that duplicate those approved via any joint program unless the duplications are justified in the original proposals. 

Joint proposals requesting ALMA time: 

• Must comply with the ALMA Users' Policies and Call for Proposals guidelines (https://almascience.org/proposing/learn-more).
• Will be allowed to request array configurations offered between the time the project will enter the ALMA queue (i.e. upon project preparation subsequent to proposal approval, as indicated in the JWST Preparation of the PDF Attachment document) until the end of the ongoing ALMA Cycle, as well as those offered in the upcoming ALMA Cycle.
• Cannot request ALMA time for VLBI or phased array observing modes. 
• Cannot be Large Programs, that is request > 50 hours on the 12-m array or > 150 hours on the 7-m array (see the ALMA Proposer's Guide for a definition of a Large Program). 

Establishing the technical feasibility of the ALMA observations is the responsibility of the PI, who should review the ALMA Proposer’s Guide or consult with the JAO. ALMA will not do a preliminary technical assessment (i.e., before the JWST TAC). Projects that during the preparation of the observations are deemed not to match  with the initial technical justification, including requested time, may be deemed unfeasible. For proposals that are approved by the JWST TAC, detailed feasibility checks will be conducted by the JAO. The JAO reserves the right to reject any previously JWST-approved observation that proves infeasible, impossible to schedule, and/or dangerous. Any ALMA observations that prove infeasible or impossible could jeopardize the overall science program and may cause revocation of the corresponding JWST observations. Duplicate ALMA observations may also be rejected by the JAO.

Technical information about the ALMA observations must be marked and provided in two different places: (1) In the "Coordinated Telescopes" section of APT, with the necessary ALMA hours request; and (2) In the "Justify Coordinated Observations with Other Facilities" section of the PDF file to be uploaded into APT. Proposers should carefully review the information required to justify Joint JWST-ALMA Observations.

Joint JWST-Chandra Observing Proposals

By agreement with the Chandra X-ray Center (CXC), the JWST TAC will be able to award up to 300 kiloseconds of Chandra observing time. Similarly the CXC will be able to award up to 150 hours of JWST time to highly rated proposals awarded Chandra time in its TAC process. The only criterion above and beyond the usual review criteria is that the project must be fundamentally of a multi-wavelength nature, and that both sets of data are required to meet the science goals.  Chandra time will only be awarded in conjunction with new JWST observations (and should not be proposed for in conjunction with an AR or Theory Proposal). Proposers should take special care in justifying both the scientific and technical reasons for requesting time on both missions.

Unless otherwise stated in the proposal, it is assumed that there is no requirement on the relative timing of the JWST and Chandra observations. A request for contemporaneous or near-simultaneous observations can be made if scientifically justified and technically feasible but there is no guarantee that these can/will be executed.

Time-constrained Chandra observations awarded in the JWST review are limited by the finite amount of Resource Cost (RC) available to the JWST review. In addition, only one rapid ToO (less than 20 days turn-around time) can be awarded. The minimum expected response time for any ToO is 24 hours after triggering a Chandra observation. JWST Cycle 5 proposers should keep their Chandra requests within these limits.

Proposals for combined JWST and Chandra observations should be submitted to the observatory that represents the prime science (not to both observatories). STScI reserves the right to disallow JWST observations that duplicate those approved via any joint program unless the duplications are justified in the original proposals. While there is multi-wavelength expertise in the review panels for both observatories, typically the JWST panels will be stronger in IR science and the Chandra panels in X-ray science.

Establishing the technical feasibility of the Chandra observations is the responsibility of the PI, who should review the Chandra documentation or consult with the CXC. For proposals that are approved by JWST, the CXC will perform detailed feasibility checks in Chandra Cycle 28. The CXC reserves the right to reject any previously JWST-approved observation that proves infeasible, impossible to schedule, and/or dangerous to the Chandra instruments. Any Chandra observations that prove infeasible or impossible could jeopardize the overall science program and may cause revocation of the corresponding JWST observations. Duplicate Chandra observations may also be rejected by the CXC.

For the health and safety of the Chandra spacecraft, the amount of Chandra exposure time available for High Ecliptic Latitude (HEL) targets with |b_Ecliptic| > 55 deg is limited. Refer to section on HEL targets in the Chandra Call for Proposals for detailed information. If you request joint time on Chandra, please avoid long exposures on such targets if at all possible. You must note explicitly the requested amount of Chandra HEL time in the body of your science justification.

HRC is limited to observing for 14.5 ks at a time with a minimum 30 ks buffer between subsequent HRC observations. HRC observations over 14.5 ks will be split accordingly. There are also restrictions for HRC observations before and after Chandra enters radiation zones. Limits on HRC usage are subject to change over the observing cycle.

Similarly, constraints that may limit the number of days your targets are observable can be difficult to accommodate within Chandra scheduling. Chandra uses Resource Cost (RC) to represent this difficulty; please refer to the Section on Resource Cost in the Chandra Call for Proposals for more detailed information. Only a fixed total number of RC points, as calculated by Chandra’s RC calculator, may be awarded by Chandra's joint partner observatories. Every proposal requesting joint Chandra time should explicitly list the RC total of their requested Chandra time in the body of the science justification, except for ToOs where the sky position is unknown. The nominal resource cost is 1.6 RC per 1 ks of Chandra observing time, however it can vary broadly based on observing constraints, sky position and exposure times. Please refer to the section on Resource Cost in the Chandra Call for Proposals for details. Additionally, the proposers must verify that Chandra will be able to acquire suitable star fields for a given target using the Star Checker tool.

Technical information about the Chandra observations must be marked and provided in two different places: (1) In the "Coordinated Telescopes" section of APT, with the necessary Chandra kiloseconds request; and (2) In the "Justify Coordinated Observations with Other Facilities" section of the PDF file to be uploaded into APT. Proposers should carefully review the information required to justify Joint JWST-Chandra Observations.

Joint JWST-HST Observing Programs

By agreement with the HST Project, the JWST TAC may nominally award 300 orbits of HST observing time. Similarly, the HST TAC may nominally award 150 hours of JWST time. The time will be awarded only for highly ranked proposals that require use of both observatories and shall not apply to Archival or Theory Proposals. The only criterion above and beyond the usual review criteria is that both sets of data of the same target(s) are required to meet the primary science goals. Proposers should take special care in justifying both the scientific and technical reasons for requesting observing time on both missions. (All Joint JWST Observing Programs are GO - no Joint JWST-HST AR proposals are offered at this time.) 

HST recently transitioned to Reduced Gyro Mode. The main impact for users is that the field of regard is reduced to approximately 40-45% of the sky, comparable with JWST. Further information can be found in the Reduced Gyro Mode Tips and Resources.

Unless otherwise stated in the proposal, it is assumed that there is no requirement on the relative timing of the JWST and HST observations. A request for contemporaneous or near-simultaneous observations can be made if scientifically justified and technically feasible but there is no guarantee that these can/will be executed.

If a science project requires observations with both HST and JWST, then a single proposal may be submitted to request time on both observatories to the JWST Announcement of Opportunity, so that it is unnecessary to submit proposals to two separate reviews. The proposal should be submitted to the observatory that requires the larger time allocation time including overheads (where 1 JWST hour is equivalent to 1 HST orbit). Since STScI operates both HST and JWST, the amount of time for JWST-HST Joint Proposals could be revised upwards if the demand is high. 

Target of Opportunity observations are allowed. Target of Opportunity (ToO) proposals must state explicitly whether the HST observations require a non-disruptive or a disruptive ToO (the latter for observations within 21 days of notification). No more than one (1) disruptive HST ToO of the joint program will be performed per HST Cycle. Furthermore, Ultra-rapid HST ToO requests (reaction time 2 days or less) will not be accepted for this program; proposals asking for Ultra-rapid HST ToO observations must be submitted in response to the HST Call for Proposals, with HST as the primary observatory. It is mandatory that the PI informs both observatories immediately if the trigger criterion is fulfilled. For this solicitation, no HST time will be allocated without the need for JWST time on the same target to complete the proposed investigation.

Joint time is not allowed to be multi-cycle; that is, the JWST GO request can be multi-cycle in nature but any joint HST time requested can only be for the current cycle.

Establishing the technical feasibility of the HST observations is the responsibility of the PI, who should review the HST Call for Proposals, Instrument Handbooks, and/or contact the HST Helpdesk. The HST Helpdesk offers new features, to search our documentation and to send your question directly to the appropriate team of experts. For proposals that are approved by JWST, STScI will perform detailed feasibility checks. STScI reserves the right to reject any previously JWST-approved observation that proves infeasible, impossible to schedule, and/or dangerous to the HST instruments. Any HST observations that prove infeasible or impossible could jeopardize the overall science program and may cause revocation of the corresponding JWST observations. Duplicate HST observations may also be rejected by the STScI.

Technical information about the HST observations must be marked and provided in two different places: (1) In the "Coordinated Telescopes" section of APT, with the necessary HST orbits request; and (2) In the "Justify Coordinated Observations with Other Facilities" section of the PDF file to be uploaded into APT. Proposers should carefully review the information required to justify Joint JWST-HST Observations.

Successful proposers will be contacted to provide an HST Phase II for their program.

Exclusive Access Periods for JWST data and HST data will be set independently following the policies for each observatory according to proposal size and type (for example, if the JWST observations are "large" and thus non-proprietary, but the HST observations are small, the HST data could be proprietary). If a user has a Joint JWST-HST or HST-JWST program and they request a waived or reduced Exclusive Access Period, it will apply to both missions. 

Joint JWST-NASA Keck Observing Proposals

By agreement with NASA HQ, the NASA Exoplanet Science Institute (NExScI) and the Space Science Telescope Institute (STScI), the JWST Telescope Allocation Committee (TAC) will award up to 10 - 15 nights of NASA Keck time during observing semesters 2026B (August 1, 2026 - January 31, 2027) and 2027A (February 1, 2027 - July 31, 2027) to highly ranked proposals that request observations from both JWST and NASA Keck. The only criterion above and beyond the usual NASA Keck review criteria is that the project must require both data sets to meet the science goals. NASA Keck time will only be awarded in conjunction with new JWST observations (and should not be proposed for in conjunction with an AR or Theory Proposal).

Unless otherwise stated in the proposal, it is assumed that there is no requirement on the relative timing of the JWST and NASA-Keck observations. A request for contemporaneous or near-simultaneous observations can be made if scientifically justified and technically feasible but there is no guarantee that these can/will be executed.

Joint proposals for JWST and NASA Keck observations should be submitted to STScI as a response to the JWST Call for Proposals. STScI reserves the right to disallow JWST observations that duplicate those approved via any joint program unless the duplications are justified in the original proposals. 

For joint proposals requesting NASA Keck time:

• May request observations in the 2026B and/or 2027A semesters. NASA Keck time awarded to a joint program will be scheduled after the start of the 2026B observing semester (August 1, 2026).
• NASA Keck data collected as part of a Joint Program will have the same Exclusive Access Period (EAP) as the JWST data.
• Keck observations approved through this joint program will be scheduled in a similar fashion to all other NASA Keck programs. NASA Keck observations lost to weather or instrument/telescope issues will not be rescheduled.
• Requests for contemporaneous/simultaneous JWST/Keck observations will be considered but cannot be guaranteed.
• Although teams may propose a similar or the same program to both the NASA Keck and JWST TACs, STScI and NExScI personnel will examine approved programs to avoid duplication of proposals/programs in the use of NASA Keck time.
• Up to 2 partner Keck Target of Opportunity/cadence interrupts can be awarded by the JWST TAC for the time period covered by the 2026B and 2027A observing semesters.
• Major results from these programs should be credited to both JWST and NASA Keck.
• NExScI will not provide funding to successful Joint Program PIs.
• Questions related to NASA Keck time specifically may be directed to keckcfp@ipac.caltech.edu

Some of the instruments available for NASA Keck 2025B observations are expected to be the same for 2026B and 2027A, but proposers should check the above website for the most up-to-date information.

Establishing the technical feasibility of the NASA Keck observations is the responsibility of the PI. NExScI will perform a technical review of the Keck portion of the joint proposals approved by the JWST TAC and reserves the right to reject any approved observation determined to be infeasible, impossible to schedule, and/or dangerous to the telescopes or instruments. Any Keck observations that prove infeasible or impossible could jeopardize the overall science program and may cause revocation of the corresponding JWST time allocation. We, therefore, urge proposers to discuss technical concerns with appropriate staff at both observatories.

Technical information about the NASA Keck observations must be marked and provided in two different places: (1) In the "Coordinated Telescopes" section of APT, with the necessary NASA Keck nights request; and (2) In the "Justify Coordinated Observations with Other Facilities" section of the PDF file to be uploaded into APT. Proposers should carefully review the information required to justify Joint JWST-NASA Keck Observations.

Joint JWST-NOIRLab Observing Proposals

By agreement with the National Science Foundation's National Optical-Infrared Astronomy Research Laboratory (NOIRLab), STScI will be able to award time on NOIRLab facilities to highly ranked proposals that request time on both JWST and NOIRLab telescopes. The award of time on NOIRLab facilities will be subject to approval by the NOIRLab Director, after nominal review by the NOIRLab TAC to avoid duplication of programs. Joint proposals for JWST and NOIRLab observations should be submitted to STScI as a response to the JWST Call for Proposals.  The important additional criterion for the award of NOIRLab time is that both the JWST and the ground-based data are required to meet the science goals of the project. Under this agreement, NOIRLab time will only be awarded in conjunction with new JWST observations (and should not be proposed for in conjunction with an AR or Theory Proposal). Major results from these programs would be credited to NOIRLab and JWST.

Unless otherwise stated in the proposal, it is assumed that there is no requirement on the relative timing of the JWST and NOIRLab observations. A request for contemporaneous or near-simultaneous observations can be made if scientifically justified and technically feasible but there is no guarantee that these can/will be executed.

NOIRLab has offered up to 5% of its available time to proposals meeting the stated criteria. NOIRLab observing time will be implemented during the NOIRLab observing semesters 2026B  and 2027A. Time cannot be requested for the preceding semester, 2026A. Time may be requested only for those facilities listed on the most recent Call for Proposals webpage. In addition, time on heavily-subscribed resources may be limited by the NOIRLab Director.

Establishing the technical feasibility of the proposed NOIRLab observations is the responsibility of the PI, who should review the NOIRLab documentation or consult with NOIRLab directly. All PIs of joint proposals MUST submit the technical description through the standard NOIRLab process by the nominal April 1, 2026 deadline for semester 2026B. For Gemini proposals, a Gemini PIT proposal must be submitted. For all other telescopes, the standard NOIRLab Time Allocation Proposal form must be submitted. Detailed information for Gemini and other telescopes can be found in the Call for Proposals for the 2026B semester (specific semester calls are not posted until 30 days before the next proposal deadline). Proposals not received by the April 1, 2026 deadline may not be scheduled for NOIRLab time.

NOIRLab will perform feasibility checks, and reserves the right to reject any approved observation determined to be infeasible, impossible to schedule, and/or dangerous to the telescopes or instruments. Any NOIRLab observations that prove infeasible or impossible could jeopardize the overall science program and may cause revocation of the corresponding JWST time allocation.

Technical information about the NOIRLab observations must be marked and provided in two different places: (1) In the "Coordinated Telescopes" section of APT, with the necessary NOIRLab nights request; and (2) In the "Justify Coordinated Observations with Other Facilities" section of the PDF file to be uploaded into APT. Proposers should carefully review the information required to justify Joint JWST-NOIRLab Observations.

Joint JWST-NRAO Observing Proposals

By agreement with the National Radio Astronomy Observatory (NRAO), STScI will be able to award time on NRAO facilities to highly ranked proposals that request time on both JWST and NRAO telescopes. For Cycle 5, NRAO has offered up to 5% of the available time on its North American facilities, namely the Robert C. Byrd Green Bank Telescope (GBT), the Very Large Array (VLA), and the Very Long Baseline Array (VLBA), for allocation by the JWST TAC in Cycle 5. In return, STScI has offered 50 hours of JWST time for allocation by the NRAO TAC to proposals submitted on or before either of the two NRAO semester deadlines. These time allocations could be updated in future cycles, subject to agreement between both partners. 

GBT MUSTANG-2 is a shared risk instrument and proposals using it should include the instrument team.

Joint observing proposals will be available starting with NRAO Semester 26B (proposal deadline February 4, 2026, with observations commencing in August 2026) and with JWST Cycle 5 (proposal deadline October 2025, with observations commencing in July 2026). Joint proposals will be permitted for the main call for JWST and both semester calls for NRAO. 

Joint JWST-NRAO Proposals should be submitted to the observatory that requires the larger time allocation. STScI reserves the right to disallow JWST observations that duplicate those approved via any joint program unless the duplications are justified in the original proposals. 

NRAO observing time awarded through the JWST Cycle 5 review will be implemented during the Cycle 26B and Cycle 27A observing semesters. The award of time on NRAO facilities will be subject to approval by the NRAO Director, after nominal review by the NRAO TAC to avoid duplication of programs. The important additional criterion for the award of NRAO time is that both the JWST and the radio data are required to meet the science goals of the project. Under this agreement, NRAO time will only be awarded in conjunction with new JWST observations (and should not be proposed for in conjunction with an AR or Theory Proposal). Major results from these programs would be credited to NRAO and JWST.

Unless otherwise stated in the proposal, it is assumed that there is no requirement on the relative timing of the JWST and NRAO observations. A request for contemporaneous or near-simultaneous observations can be made if scientifically justified and technically feasible but there is no guarantee that these can/will be executed.

Establishing the technical feasibility of the proposed radio observations is the responsibility of the PI, who should review the NRAO documentation or consult with NRAO directly. If approved for NRAO time, the PI must submit detailed observing information appropriate to the relevant NRAO facility. 

NRAO will perform a technical review of proposals approved by the JWST TAC, and reserves the right to reject any approved observation determined to be infeasible, impossible to schedule, and/or dangerous to the telescopes or instruments. Any NRAO observations that prove infeasible or impossible could jeopardize the overall science program and may cause revocation of the corresponding JWST time allocation. We therefore urge proposers to discuss technical concerns with appropriate staff at both observatories. Discussions with NRAO staff should occur via the NRAO helpdesk.

Proposers must always check whether appropriate archival data exist, and provide clear scientific and technical justification for any new observations of previously observed targets. Observations awarded time that duplicate observations already approved by JWST or NRAO for the same time period may be canceled, or data sharing and cooperation among different groups may be necessary, as determined by the two observatories. This includes ToOs with similar trigger criteria, with or without previously known coordinates.

Be aware that some JWST targets might not require new NRAO observations because the joint science goals can be met using non-exclusive access archival data from the VLA, VLBA, or GBT that are available at http://data.nrao.edu. Also note that VLA continuum images from sky surveys at a wavelength of 20 cm and at a FWHM resolution of 45 arc seconds (see http://www.cv.nrao.edu/nvss/) or 5 arc seconds (see http://sundog.stsci.edu/top.html) are available.

All scientific data from NRAO telescopes have an exclusive access period where the data are reserved for the exclusive use of the observing team. This policy applies to NRAO data taken through the joint JWST-NRAO program.

Technical information about the NRAO observations must be marked and provided in two different places: (1) In the "Coordinated Telescopes" section of APT; and (2) In the "Justify Coordinated Observations with Other Facilities" section of the PDF file to be uploaded into APT. Proposers should carefully review the information required to justify Joint JWST-NRAO Observations.

Joint JWST-TESS Observing Proposals

By agreement, STScI will be able to award a limited number of short cadence target slots from the Transiting Exoplanet Survey Satellite (TESS) mission. Currently in its third extended mission, TESS will be observing fields in both the northern and southern ecliptic hemispheres in addition to parts of the ecliptic plane. TESS operates by staring at one part of the sky for two spacecraft orbits (2x approximately 14 days) with the boresight of the four-camera array pointed nearly antisolar. During each of these continuous pointings, referred to as Sectors, TESS collects 200 second Full Frame Images (FFIs) which cover a 24 x 96 degree field of view, and 120-second or 20-second cadence Target Pixel Files (TPF) - postage stamps for selected targets of interest. After this ~27 day coverage, TESS slews to observe a different Sector of sky for another ~27 days. All TESS observations are collected in a single, broadband, red- optical bandpass.

Information about the specific TESS pointings for upcoming sectors will be released around September 15, 2025 and will be available on the TESS General Investigator (GI) Program Office website and the MIT TESS website.

TESS 120-second and 20-second targets selected for postage stamps are pipeline processed for background subtraction, and are delivered to MAST as both pixel products and time-series light curve products with no proprietary period. Calibrated TESS FFI’s are observed at a 200 second cadence, provide no target apertures, and have not had scattered or background light subtracted. TESS FFIs are available to the community via MAST with no proprietary period. Programs requiring finer time sampling than the FFI data and/or pipeline processed time-series products should propose to the joint JWST-TESS program and request specific TESS targets. Proposals relying solely on the TESS FFI data do not need to be proposed for through the JWST-TESS joint program.

The joint JWST-TESS program can allocate 120-second cadence observations for up to 1,000 targets and 20-second cadence observations for up to 50 targets. Proposers should identify which targets should be considered for TESS observations and provide an explicit justification that a 120-second or 20-second cadence is sufficient to achieve their science goals. TESS observations will only be obtained for approved JWST targets. There is no guarantee that the JWST and TESS observations will be simultaneous. Joint program targets will be observed by TESS no earlier than the beginning of JWST Cycle 5 observations. Accepted targets will be passed to the TESS GI Program Office by STScI. Additional information about TESS can be found on the TESS GI Program Office website.

Technical information about the TESS observations must be marked and provided in two different places: (1) In the "Coordinated Telescopes" section of APT; and (2) In the "Justify Coordinated Observations with Other Facilities" section of the PDF file to be uploaded into APT. Proposers should carefully review the information required to justify Joint JWST-TESS Observations.

Joint JWST-XMM-Newton Observing Proposals

By agreement with the XMM-Newton Observatory, the JWST TAC may award up to 200 kiloseconds of XMM-Newton observing time. Similarly, the XMM-Newton Observing TAC may award up to 40 hours of JWST time to highly rated proposals. The only criterion above and beyond the usual review criteria is that the project must be fundamentally of a multi-wavelength nature, and that both sets of data are required to meet the science goals. XMM-Newton time will only be awarded in conjunction with new JWST observations (and should not be proposed for in conjunction with an AR or Theory Proposal). Proposers should justify the scientific and technical reasons for requesting time on both missions.

If your science project requires observations from both JWST and the XMM-Newton Observatory, you can submit a single proposal to request time on both observatories to either the JWST Cycle 5 or the XMM-Newton Cycle AO-26 review. Joint JWST/XMM-Newton Proposals should be submitted to the observatory that represents the prime science facility (not to both observatories). 

Unless otherwise stated in the proposal, it is assumed that there is no requirement on the relative timing of the JWST and XMM-Newton observations. A request for contemporaneous or near-simultaneous observations can be made if scientifically justified and technically feasible but there is no guarantee that these can/will be executed. 

No XMM-Newton observations with a reaction time of less than five working days from the trigger date will be considered. Target of Opportunity (ToO) Proposals must state explicitly whether the JWST observations require a disruptive ToO. No more than one disruptive ToO will be allocated per proposal. It is the responsibility of the PI to inform both observatories immediately if the trigger criterion is fulfilled.

STScI reserves the right to disallow JWST observations that duplicate those approved via any joint program unless the duplications are justified in the original proposals. While there is multi-wavelength expertise in the review panels for both observatories, typically the JWST panels will be stronger in IR science and the XMM panels in X-ray science.

Establishing the technical feasibility of the XMM-Newton observations is the responsibility of the PI, who should review the XMM-Newton Instrument Handbooks. All standard observing restrictions for both observatories apply to joint proposals. For proposals that are approved, both projects will perform detailed feasibility checks. Both projects reserve the right to reject any approved observation that is in conflict with safety or schedule constraints, or is otherwise deemed to be non-feasible.

Technical information about the XMM-Newton observations must be marked and provided in two different places: (1) In the "Coordinated Telescopes" section of APT, with the necessary XMM-Newton kiloseconds request; and (2) In the "Justify Coordinated Observations with Other Facilities" section of the PDF file to be uploaded into APT. Proposers should carefully review the information required to justify Joint JWST-XMM-Newton Observations.

Survey Programs

Survey programs will be used for two main purposes in Cycle 5: supplementing the Long Range Plan (LRP) to maintain observing efficiency if there is a shortfall of GO programs; and providing simple observations that can be executed when data volume is constrained by external factors. JWST Survey programs are analogous to Snapshot (SNAP) programs on the Hubble Space Telescope.

Proposers may request short (typically <100 minutes of charged time) observations using different instrument configurations and/or total durations.  Proposals must include one example of each type of observation in APT; if proposers are only using one configuration, then only one example observation is required; if there are two configurations, provide one example for each. The APT form includes two fields specific to Survey programs:

•  "Targets Requested" (on the Observation form), where the proposer enters the number of targets associated with each example; and
•  "Total Targets Requested" (on the Proposal Information form), giving the total targets in the program. This field is calculated automatically by APT by summing all targets associated with each example included the proposal. 

NIRSpec MOS and MIRI MRS are not available for Survey programs. All other observing modes are allowed, assuming the observations follow the specifications described in this section. 

There is no guarantee that any individual observation will be executed. The number of Survey observations planned for each cycle depends on the distribution of GO/GTO observing time across the LRP. In general, only a small fraction of the targets will be planned for scheduling and execution. Survey programs are lower priority and may be dropped if there are conflicts with other observations on a Short Term Schedule.

We anticipate that up to 1,000 Survey targets may be planned for Cycle 5. The TAC will select programs requesting up to 1,000 targets to provide appropriate sky coverage to support both planned and unplanned use of Survey observations. All accepted Survey programs terminate at the end of Cycle 5.

There is no commitment on the part of STScI to obtain any specific completion factor for Survey programs. The average expected completion rate for Survey programs is ~20%. However, the actual completion rates for individual programs vary, depending on several factors including the number of targets and the average duration and sky distribution of the observations. In general, shorter-duration and well-distributed survey observations have a higher number of scheduling opportunities and a higher chance of being executed than longer duration and/or spatially clustered survey observations.

Survey programs have the following characteristics:

• Proposers request observations of a specific number of targets, not to exceed 1000 targets per proposal.
  
• Proposers are not required to give a complete list of all targets and their coordinates at the time of submission. Example observations for each type of observation must be provided (along with the number of targets requested for each example) in APT. Both the "Abstract" in the APT Proposal Information form and the "Scientific Justification" section of the PDF attachment must describe the target distribution on the sky and unambiguously identify the targets (e.g., reference to target lists in papers) or give a detailed description of their characteristics. Accepted programs will be required to submit the full target list within one month of the notification of acceptance.
  
• Proposers must specify the minimum number of targets required to achieve the science goals. Proposers can also indicate if there is an optimal number of targets, if that is different than the minimum. This information must be included in the "Scientific Justification" section of the proposal.  
• Survey proposals must include a "Technical Justification" section in the PDF attachment.
• Survey programs may not be used for Targets of Opportunity.
• Observations of any particular target cannot be guaranteed; the point of the Survey program is to have many different options from a class of objects that can be inserted into the observing schedule. Survey Proposals must target sources distributed over a wide range of Right Ascension (given the JWST Target Observability and Observatory Coordinate System) to ensure that potential targets are readily available for scheduling. Targets at high ecliptic latitude are particularly useful since they have longer visibilities. Examples of programs that are not well suited to Survey Proposals (because they do not help improve scheduling efficiency) are surveys of targets confined to a restricted region (e.g., M31 or M33) or surveys limited to a few targets (e.g., surveys of two or three specific galaxy clusters). 
• Moving targets are acceptable as long as their angular rate is below 10 mas/s = 0.24 deg/day.
• Proposers should minimize the data volume for their visits. See JWST Data Volume and Data Excess for guidance. 
• Observations should have minimal constraints to maximize their schedulability.
• Timing and orientation constraints on individual or between (linked) Survey observations are not permitted.
• In the case of duplication, GO proposals have priority over Survey Proposals since observations of an individual Survey target are not guaranteed.
• Proposers may not assign priorities to individual observations in a Survey program. Targets will be selected for execution based on the available observatory resources.
• In general, shorter-duration, lower data-volume, and spatially well-distributed Survey targets have a higher number of scheduling opportunities and a higher chance of being executed than longer duration, high data-volume, and/or spatially clustered Survey observations.
• Cycle 5 Survey Proposals may only request time in Cycle 5; they may not request observations in future cycles.
• Survey proposals may not be Calibration Proposals.

All Survey proposals have a default Exclusive Access Period of 12 months. However, because of the potential benefit to the community at large, proposers should consider seriously the possibility of requesting a shorter Exclusive Access Period of 0, 3 or 6 months. While this is not a primary criterion for acceptance or rejection, the reduced period can bring additional benefits to any proposal and will be weighed by the reviewers accordingly (see JWST Proposal Selection Procedures).

All Survey proposals, regardless of size, have a 4+1 page limit (the additional page is available only for the following sections: "Special Requirements", "Justify Coordinated Parallel Observations", and "Justify Duplications"), as described in JWST Preparation of the PDF Attachment.

Survey proposals, regardless of size, will be reviewed by the Discussion panels, but the requested observing time is drawn from a separate pool. Further details on the review process are given in JWST Proposal Selection Procedures.

Archival Research (AR) Proposals

Observations with no Exclusive Access Period or that are no longer in the Exclusive Access Period are freely available for analysis by scientists through retrieval from the Mikulski Archive for Space Telescopes (MAST). 

The JWST Archival Research (AR) Program can provide financial support for the analysis of such data sets (as Regular or Legacy AR Proposals), or the theory (as AR Theory Proposals), cloud computing (as AR Cloud Computing Proposals), or science software (as AR Data Science Software Proposals) which maximize their use. There is also an opportunity to support calibration activities (as Calibration AR Proposals) beyond what is produced by the standard calibration pipeline. Combined GO+AR Proposals are also allowed. The data sets of interest have to be public in the  MAST archive by the beginning of Cycle 5 (July 1, 2026). No Joint JWST-HST AR proposals are offered at this time.

The "Scientific Justification" section of the PDF attachment should describe how the project improves upon or adds to the previous use of data. All AR Proposals must include an "Analysis Plan" in the PDF attachment.

AR proposals may be submitted by non-US PIs if there are US co-Is who request funding.

Investigators are allowed to submit an AR proposal to analyze data that was obtained in a previous GO Program on which they were themselves PI or Co-I, but only if the goals of the AR proposal differ significantly from those for which GO funding was awarded previously.

STScI encourages the submission of AR proposals that combine JWST data, as the main data set, with data from other space-missions or ground-based observatories, especially those data contained in the Mikulski Archive for Space Telescopes (MAST). STScI is an active partner of the Virtual Observatory (VO), and MAST is implementing VO technology to make its data holdings available. In particular, the MAST Data Discovery Portal is available at http://mast.stsci.edu/explore. The Discovery Portal is a one-stop Web interface to access data from all of the MAST supported missions, including HST (in particular the Hubble Legacy Archive- HLA, and Hubble Source Catalog- HSC), TESS, Kepler, GALEX, FUSE, IUE, EUVE, and Swift-UVOT.

AR proposals may include a citizen science component, ground-based observations, and laboratory astrophysics in support of the science goals. Funded support for those activities must be compliant with the STScI General Grant Provisions (GGP) and is limited to no more than 10% of the total budget. NASA document SPD-33 provides guidelines on citizen science projects. 

Proposals for AR funding are considered by the same reviewers as proposals for observing time and on the same basis. Regular AR proposals will be reviewed by the External panels. The Executive Committee (EC) will review Legacy AR programs. Further details on the review process are given in JWST Proposal Selection Procedures.

Regular AR Proposals

The general goal of a Regular AR Proposal is to analyze a subset of data from JWST to address a specific scientific issue. In general, the scientific questions addressed should differ from those tackled by the original programs that obtained the data. A strong justification must be given to reanalyze data if the new project has the same science goals as the original proposal. JWST funding is allocated via a formula, the exact value that will be allocated to Regular AR programs in Cycle 5 is not yet known and will depend on the final accepted science program. Budget plans should be commensurate with the level of work required to carry out the goals of the proposal.

Regular AR Proposals have a 4+1 page limit (the additional page is available only for the "Special Requirements" section, if required), as described in JWST Preparation of the PDF Attachment.

Legacy AR Proposals

A Legacy AR Proposal is defined by the following characteristics:

• The project should perform a homogeneous analysis of a well-defined subset of data from JWST in MAST.
• The main goal should be to provide a homogeneous set of calibrated data and/or ancillary data products to the scientific community.
• The results of the project should enable a variety of new and important types of scientific investigations.

We encourage the development of open source community software tools for dissemination to the community.

The main difference between a Regular and a Legacy AR Proposal is that the former aims at performing a specific scientific investigation, while the latter will also create data products and/or tools for the benefit of the community. While Legacy AR Proposals will be judged primarily on the basis of scientific merit, the importance and broad applicability of the products produced by the Legacy AR Proposal will be key features in judging the overall scientific merit of the proposal.

It is a strict requirement for Legacy AR Proposals that the proposed data products be created and distributed to the community in a timely manner. Data products should also be delivered to STScI in a format consistent with the MAST High-Level Science Products Contributions Guidelines for dissemination via MAST.

Legacy AR Proposals are larger in scope and allocated funds than Regular AR Proposals. Funding will be allocated via a formula. The amount of funding allocated to Legacy AR programs in Cycle 5 is not yet known and will depend on the final accepted science program. Commensurate with the expected scope, Legacy AR Proposals are allowed to be multi-year projects, although this is not a requirement. Multi-year projects will be funded on a yearly basis, with continued funding beyond the first year subject to a performance review. Legacy AR Proposals will be evaluated by the EC, in conjunction with Large GO, Treasury GO, and Pure Parallel Proposals, as described in JWST Proposal Selection Procedures.

The "Scientific Justification" section of the proposal's PDF attachment should include a description of the scientific investigations that will be enabled by the final data products, their importance, and value to the astronomical community. The "Analysis Plan" section should describe the plans for data analysis, the data products that will be made available to STScI and the community, the method of dissemination, and a realistic timeline. It is a requirement that data products be delivered to STScI in suitable digital formats for further dissemination via the MAST Data Archive or related channels. Any required technical support from STScI and associated costs should be described in detail.

Legacy AR Proposals have a 6+1 page limit (the additional page is available only for the "Special Requirements" section, if required), as described in JWST Preparation of the PDF Attachment.

Investigators submitting Legacy AR proposals must select the "Legacy" flag on the APT Proposal Information form.

Additional AR flags (optional)

Regular and Legacy AR Proposals can have additional "flags" to highlight particular features of those programs. These additional flags are optional (not every AR program will need one). Proposals may include multiple flags (though some specific combinations are not allowed). These flags include Calibration AR, AR Theory, AR Cloud Computing, and AR Data Science Software, and each has additional requirements that need to be met. These flags correspond to selectable options and expandable menus on the Proposal Information form in APT.

Calibration AR Proposals

Calibration Proposals may be submitted as AR Proposals. Calibration AR Proposals are appropriate in cases where the necessary data have already been taken, or for programs that do not require specific data but aim to develop specialized software for certain JWST calibration and data reduction tasks. 

Calibration AR Proposals will be reviewed internally at STScI after the proposal deadline (and before the TAC Review Meeting). The internal review will provide the TAC with an assessment of the feasibility of the proposal, how the proposal complements/extends the existing calibration program, and the type of science impacted by the proposed calibrations. Proposers should summarize the relevance and overall scientific utility of the calibration techniques and products described in their proposal. The "Scientific Justification" should describe what science will be enabled by the successful completion of the program, and how the currently supported core capabilities, their calibrations, and the existing data processing are insufficient to meet the requirements of this type of science. The "Analysis Plan" should discuss what documentation, and data products and/or software will be made available to STScI to support future observing programs. Proposers should explain how their programs complement ongoing calibration efforts by the STScI instrument groups. They should contact the relevant instrument groups to ensure that efforts are not duplicated, and if they are, justify why the duplications are necessary.

Successful proposers will be required to deliver documentation, data products, and/or software to STScI to be made available to the community to support future observing programs or archival research. Funding is available to support Calibration AR Proposals in the same manner as for normal science programs, with the following exception: Scientists affiliated with STScI are not eligible for any funding to support their role (as PI, Co-PI, or Co-I) in a Calibration Proposal.

Investigators interested in submitting a Calibration AR proposal are encouraged to study the JWST User Documentation to determine the level at which STScI provides calibration and characterization. 

Investigators submitting Calibration AR proposals must select the "Calibration" flag on the APT Proposal Information form.

AR Theory Proposals

Proposers may request financial support for theoretical research that is relevant to the JWST mission and that will have a lasting benefit for current or future observational programs with JWST.

An AR Theory proposal should address a topic that is of direct relevance to JWST observational programs, and this relevance should be explained in the proposal. Funding of mission-specific research under the JWST Theory Program will be favored over research that is appropriate for a general theory program, such as the NASA Science Mission Directorate Astrophysics Theory Program. The primary criterion for an AR Theory proposal is that the results should enhance the value of JWST observational programs through their broad interpretation (in the context of new models or theories) or by refining the knowledge needed to interpret specific observational results (a calculation of atomic cross sections may fall under the latter category). The results of the theoretical investigation should be made available to the community in a timely fashion.

AR Theory proposals can be Regular or Legacy AR proposals; the corresponding page limits, review process, and award levels are applicable.

AR Theory programs are funded like Regular AR or Legacy AR programs. The effort detailed in the "Analysis Plan" of the proposal should be commensurate with the level of funding to be requested in the budget submission. Theoretical research should be the primary or sole emphasis of an AR Theory proposal. Analysis of archival data may be included, but should not be the main aim of the project. GO or AR proposals which include a minor component of theoretical research will be funded under the appropriate GO or AR program. 

An AR Theory proposal may be submitted by a non-U.S. PI if there are one or more U.S. Co-Is who request funding. 

The "Scientific Justification" section of the proposal should include a description of the scientific investigations that will be enabled by the successful completion of the program and their relevance to JWST. The "Analysis Plan" section of the proposal should discuss the types of JWST data that will benefit from the proposed investigation, and references to specific data sets in MAST should be given where possible. This section should also describe how the results of the theoretical investigation will be made available to the astronomical community, and on what time-scale the results are expected.

Investigators submitting AR Theory proposals must select the "Theory" flag on the APT Proposal Information form.

Review panels will consist of observational and theoretical astronomers with a broad range of scientific expertise. They will not necessarily have specialists in all areas of astrophysics, particularly theory, so the proposals must be written for general audiences of scientists.

AR Cloud Computing Studies 

All non-exclusive access data for JWST instruments (MIRI, NIRCam, NIRSpec, NIRISS) will be made available as part of the Amazon Web Services (AWS) public dataset program (aws.amazon.com/public-datasets/). Providing these data in close proximity to AWS facilitates new types of compute-intensive analyses that may have not previously been possible due to individual researcher or research group compute resources. Proposals to make use of this dataset are eligible to be AR Cloud Computing Studies proposals, and proposers should be prepared to include a line item in their budget for AWS costs (limit $10,000).

Example use cases for leveraging these data could include: Large scale (re)analyses of data to measure photometric properties or proper motions, computationally-intensive tasks such as training machine learning classifiers, and live community-facing services.

Further reading:

• Link to JWST data on AWS: https://registry.opendata.aws/jwst/
• AWS machine learning services: aws.amazon.com/machine-learning/
• AWS spot computing: aws.amazon.com/ec2/spot/spot-and-science/
• Educational & research use cases: aws.amazon.com/government-education/research-and-technical-computing/

AR Cloud Computing Studies proposals can be Regular or Legacy AR proposals; the corresponding page limits, review process, and award levels are applicable.

Investigators submitting AR Cloud Computing Studies proposals must select the "Cloud Computing" flag on the APT Proposal Information form.

Review panels will consist of observational and theoretical astronomers with a broad range of scientific expertise. They will not necessarily have specialists in all areas of astrophysics, particularly cloud computing, so the proposals must be written for general audiences of scientists.

AR Data Science Software Proposals

Proposers have an opportunity under the JWST AR Program to obtain financial support for the development of software products that will be made available to the community for the purposes of analyzing JWST data. Descriptions of the data products created by the JWST calibration pipeline and related software tools are available at JWST Calibration Status, JWST Science Calibration Pipeline, and JWST Post-Pipeline Data Analysis. Examples of additional products include, but are not restricted to:

• scripts to mitigate artifacts from specific detectors,
• tools to identify and extract fluxes/magnitudes from multiple sources within a field,
• utility software for working with JWST data products, or
• codes to produce background-subtracted spectra or software to interact with JWST archive services.

The primary criterion for an AR Data Science Software Proposal is that the results should broadly enhance the value of JWST observational products for anyone in the astronomical community. The results of the data science software development should be made available to the community in a timely fashion through an appropriate distribution platform. Open source software using a standard license (https://opensource.org/licenses) is encouraged. The software should have thorough internal documentation at a level consistent with software best practices, and, if computationally intensive, should be compatible with a cloud computing service. 

There is no limit to the amount of funding that may be requested, but it is expected that the amounts will be at a similar level to those in the Regular AR category; the corresponding page limits, review process, and award levels are applicable. The effort detailed in the "Analysis Plan" should be commensurate with the level of funding requested. 

The "Scientific Justification" section of the proposal should describe how the software packages that will be developed are relevant to and necessary for the reduction or interpretation of JWST data. The "Analysis Plan" section of the proposal should discuss the types of JWST data that will benefit from the proposed investigation, and references to specific data sets in MAST should be given where possible. This section should also describe how the results of the investigation will be made available to the astronomical community, and on what time-scale the results are expected.

Investigators submitting an AR Data Science Software proposal must select the "Data Science Software" flag on the APT Proposal Information form.

Review panels will consist of observational and theoretical astronomers with a broad range of scientific expertise. They will not necessarily have specialists in all areas of astrophysics, particularly software development, so the proposals must be written for general audiences of scientists.

Next: JWST Special Initiatives