LCCF Allocations
Getting an Allocation on Horizon
Early Operations Period
All activities of the LCCF project support the overriding project goal of “discovery at the frontiers of science and engineering…through large scale simulation, data analysis, and artificial intelligence applications.” In the context of Horizon, this means enabling CPU and GPU computing capability, high speed storage, and interactive capabilities. Horizon offers an order of magnitude performance improvement over the previous Frontera system.
To receive an allocation on Horizon, proposers must show compelling science or engineering challenges that require large scale computing resources, and they must be prepared to demonstrate that they can effectively exploit the computing capabilities offered by the system. Proposals from or including junior researchers are encouraged, as one of the goals of this project is to build a community capable of using computing at the highest scales. The Horizon team will offer consulting support and assistance to each project team that is granted access through the solicitation.
We are offering one allocation track at this time. Other opportunities designed to accommodate a wider range of research needs will be available in the future. The first Horizon opportunity will open for demonstrating large scale science, with submissions opening April 15th 2026, and rolling reviews beginning May 15th. The start date for system access is anticipated in the Summer of 2026.
Early Operations Period - Leadership Resource Allocation (LRAC)
Large allocations from 125,000 to 500,000 SUs (Horizon) and up to 50,000 (Vista) for six months duration will be offered to science teams with a strong scientific justification for access to a leadership-class computing resource to enable research that would otherwise not be possible. Successful applicants must demonstrate readiness to use the allocated cycles, as well as current peer-reviewed research funding to support the activities conducted on Horizon. LRAC submission opportunities are anticipated twice per year, during production operations.
Horizon Allocation Submission Guidelines
TACC’s Horizon Leadership-Class Computing resource is provided through funding from the National Science Foundation (NSF). Horizon provides a mix of CPU and GPU computing resources, including 4,750 Dell/NVIDIA Vera CPU nodes, and 2,000 Dell/NVIDIA Grace-Blackwell nodes. Details of the architecture and capabilities can be found in the user guide.
Please thoroughly read this entire page so that you will be prepared to submit a high-quality proposal containing the documentation pertaining to eligibility, a description of the research to be performed using the testbed and sources of research support, and justification of the amount of SUs requested.
- You will submit your allocation request via the Resource Allocation System.
- Only Principle Investigators (PIs) may submit a Horizon allocation request.
- Submission period: April 15, 2026 - June 15, 2026 (rolling reviews will begin May 15th)
This informational video on previous LRAC submissions for Frontera is available for reference.
Eligibility
Horizon is broadly available to any U.S. researcher working in open research. By “open,” the expectation is that any research performed on Horizon will result in publication in a broadly available journal or conference.
An allocation on Horizon is headed by a project PI, typically a faculty member or research scientist at a US-based academic institution. The PI may then add additional investigators, including students, to their allocation at their discretion. PIs are responsible for ensuring that any users added to their allocation comply with the terms and conditions for use of the Horizon resource. Collaborative projects involving non-U.S. researchers are allowed provided they include substantive intellectual participation by the U.S. researchers.
Only Principle Investigators (PIs) may submit a Horizon allocation request. While a PI is typically a research scientist or faculty member at an academic institution, there are a number of other cases where an individual may be eligible to be a PI:
NSF Graduate Student Fellows
While in most cases, a graduate student is ineligible to be a PI of an allocation request, an exception is made for NSF Graduate Student Fellows.
Frontera Fellows
While in most cases, a graduate student is ineligible to be a PI of an allocation request, an exception is made for Frontera Fellows.
Other federal agencies
Research staff employed by federal agencies or non-NSF FFRDCs are eligible to apply for an allocation if their agency or center does not typically provide research staff with access to resources of adequate scope for the planned research, and the research to be performed will be openly published.
State educational offices or organizations and local school districts
State educational offices or organizations and local school districts may submit allocation requests intended to broaden the impact, accelerate the pace, and increase the effectiveness of improvements in science, mathematics, and engineering education in both K-12 and post-secondary levels. A teacher or educator at an accredited public or private K-12 school is eligible to apply for an allocation as PI.
Independent museums, observatories, libraries, research laboratories, professional societies and similar organizations
Independent museums, observatories, libraries, research laboratories, professional societies and similar organizations in the United States that are directly associated with educational or research activities are eligible.
U.S. commercial organizations, especially small businesses with strong capabilities in scientific or engineering research or education
U.S. commercial organizations, especially small businesses with strong capabilities in scientific or engineering research or education may apply for an allocation. The Horizon Project is interested in supporting projects that couple industrial research resources and perspectives with those of universities; therefore, it especially welcomes requests from cooperative projects involving both universities and the private commercial sector. It is necessary for these projects to submit their work in an open forum, and make the results of this work readily available to the public.
- NSF Graduate Student Fellows: While in most cases, a graduate student is ineligible to be a PI of an allocation request, an exception is made for NSF Graduate Student Fellows.
- Other federal agencies: Research staff employed by federal agencies or non-NSF FFRDCs are eligible to apply for an allocation if their agency or center does not typically provide research staff with access to resources of adequate scope for the planned research.
- A teacher or educator at an accredited public or private K-12 school is eligible to apply for an allocation as PI. State educational offices or organizations and local school districts may submit allocation requests intended to broaden the impact, accelerate the pace, and increase the effectiveness of improvements in science, mathematics, and engineering education in both K-12 and post-secondary levels.
- Independent museums, observatories, libraries, research laboratories, professional societies and similar organizations in the United States that are directly associated with educational or research activities
- U.S. commercial organizations, especially small businesses with strong capabilities in scientific or engineering research or education may apply for an allocation. The Horizon Project is interested in supporting projects that couple industrial research resources and perspectives with those of universities; therefore, it especially welcomes requests from cooperative projects involving both universities and the private commercial sector. It is necessary for these projects to submit their work in an open forum, and make the results of this work readily available to the public.
Allocation Metrics
How is my time on Horizon charged?
Compute time on Horizon is allocated in Service Units (SUs). A Horizon SU is defined as one wall-clock hour on a Grace-Blackwell (GB200) node, consisting of one 72-core CPU and two Blackwell GPUs. CPU nodes on Horizon, which consist of two 88-core Vera CPUs, will be charged at one-fourth the GPU node rate (One SU = 4 CPU node hours). Note the GPU portion of Horizon will be available first, in summer of 2026. The CPU portion will not be made available to users until the end of 2026, or perhaps early 2027, depending on processor delivery schedules.
Allocation Tracks
Horizon currently has only a single submission track, though others will be available once the system enters production, including small start up requests, classroom requests, community and partnership requests, etc.
LCCF Resource Allocations
Description and Need: Ultimately all activities of the Horizon project support the overriding project goal as articulated in the NSF program solicitation: “serve as a national resource for providing predictable and sustained long-term leadership computing capabilities for science and engineering to push the frontiers of knowledge….” In the context of Horizon, this means enabling computation-based scientific discovery, with a particular focus on science at the largest scales. The computation based work may be AI, simulation, or data analysis. “Large scale” may mean the need for single large runs (capability computing), or a high volume of smaller computations (capacity computing).
Mechanism of Award: Potential awardees will submit an allocation proposal to a peer review panel of independent experts that the Horizon team will invite and organize. Recommendations for award will be sent to NSF for their review and consensus agreement. Horizon allocations are highly competitive, and the highest ranked proposals are awarded as close to their requested amount as possible depending on availability. Accordingly, lower ranked proposals will be reduced significantly. Deadlines will be at least once per year, possibly twice depending on availability of time. In an attempt to align allocations with research funding, while awards will be made for one year, annual renewals will be available until the end of the associated grant with a progress report verifying level of usage, publications, and progress towards research goals and also a computational plan for the coming year. There will be no extensions for existing allocations, thus a renewal submission is required annually regardless of remaining allocation balance.
Allocation Size Limits: LRAC requests can be submitted for up to 500k SUs for the early operations period for Horizon. Note that this represents nearly 5% of the full system annual capacity, so we expect typical requests to be much smaller. The minimum size for a LRAC request is 125,000 SUs for the six month period. For Vista, requests can be submitted for up to 50K SUs per year, with no minimum. For significantly underutilized allocations, we reserve the right to reduce the remaining allocation balance during the second half of the award period.
Allocation time: For the early operations period awards will cover a 6 months period. Subsequent allocation cycles will change to year-long award periods.
Proposals and Review Criteria
Horizon allocations are reviewed for merit by a committee consisting of members of the resource allocation board. The board is made up of researchers in the academic community with support from members of the project team. The board makes recommendations to the project based solely on the merit of the proposal, and not on overall availability of the resource. The board will review the proposal and make a recommendation to the project team based on the following criteria:
- Intellectual Merit: Is the proposed work supported by a grant or grants that have undergone review for intellectual merit and/or broader impact (if relevant to the allocation)? If so, is the allocation request consistent with the objectives of the supporting grants and is the scale of resource use commensurate with the level and purpose of support? If a request is not supported by a merit-reviewed award, reviewers will assess the intellectual merit of the proposed work and factor that into their overall recommendation. Reviewers will also consider whether the identified support provides necessary and sufficient human resources to complete the proposed work.
- Appropriateness of Methodology: Does the request describe appropriate tools, methods, and approaches for addressing the research objectives? These methodologies may be community codes or models, data analysis methods, or algorithmic formulations expressed in user-developed scripts or tools. Is this methodology appropriate for use on Horizon?
- Appropriateness of Research Plan: Does the request describe necessary and sufficient computational experiments to answer the research questions posed? In some cases, the research plan may be more reasonably expressed as estimates of resource use, supported by past or early experience. Serious concerns about the research plan will be documented in reviews and may lead to reduced allocation awards.
- Efficient Use of Resources: Has the request identified appropriate resources for undertaking the research plan with the proposed methodology? And will those resources be used as efficiently as is reasonably possible?
- Demonstrated need for a large scale resource.
Proposals that are deemed competitive by the project advisory board are then reviewed by the project team for technical feasibility (i.e, can the project be implemented in the Horizon environment?) and for the availability of time on the resource. Horizon allocations are highly competitive, and the highest ranked proposals are awarded as close to their requested amount as possible depending on availability. Accordingly, lower ranked proposals will be reduced significantly. Recommended proposals will then be sent to NSF for final approval.
Conflict of Interest and Confidentiality
Every effort is made to avoid conflicts of interest. Reviewers are not allowed to review or be present for the discussion of requests from their home institution, former students, postdocs, advisors, or current and recent collaborators. If in the opinion of a PI, a certain individual has a conflict of interest, the PI may request that the individual not act as reviewer on their request. All reviews remain confidential, and are made available only to: The PI and Co-PIs submitting the request, assigned reviewers from the Advisory Committee, project staff involved in the allocation review process, and NSF program officers for the project.
While the contents of reviews and details of allocation requests and experiments remain confidential, a list of projects receiving allocations and the general area of research may be made public on the project web site and used in project reports and presentations.
Supplemental Requests
A supplement is a request for additional resources during an existing allocation’s one year time frame. Its purpose is to support changes in the original computational research plan that are required to achieve the scientific goals of the project. This may include altered or new goals, or support for projects proceeding more rapidly than anticipated or that require more resources than anticipated. Supplement awards are highly dependent upon availability of resources and limited to when allocation awards at the previous allocation period have been reduced to eliminate oversubscriptions. Supplements are not a mechanism to acquire additional resources for awards that were recommended for less than the amount originally requested. Supplemental requests require the filing of a progress report that documents what has been done with the originally awarded allocation, and makes the case for additional resources.
Proposal Format
LRAC Submissions Requests
When writing your LRAC request, be clear and concise. We strive to have domain experts review every request, but they may not have deep expertise in your specific subdomain. Someone outside of your area should be able to understand the scientific objectives and understand why the chosen technique is preferred over another.
The documents required of a new LRAC request ensures reviewers can effectively determine how each request satisfies the Horizon allocation Review Criteria. LRAC requests are limited to 10 pages.
Research requests must include a well-documented resource-use plan that describes how the requested allocations are necessary and sufficient to accomplish the project’s research objectives. An effective resource-use plan must address the Horizon allocation Review Criteria and, in particular, must include the following elements:
- Scientific Background
- Research Objectives and specific questions to be pursued
- Resource Usage Plan to achieve the research objectives
- Justification of the allocation amounts for all resources and resource types
- Declaration of access to other CI resources and why those resources are not available or insufficient for the work proposed in the request
PAGE LIMIT: 10 pages
References
A PI may use this OPTIONAL document to separate a lengthy bibliography of cited work to take full advantage of the page limits in the Main Document. This bibliography is not necessarily the publications resulting from prior LCCF support, which should be entered into the LCCF publications database, but rather other citations referenced in describing or supporting the intellectual merit of the proposed work or the appropriateness of the proposed approach for addressing the research objectives.
PAGE LIMIT: No limit
Document Formatting
While readability is of greatest importance, documents must satisfy the following minimum requirements. Documents that conform to NSF proposal format guidelines will satisfy these guidelines.
Margins
Documents must have 2.5cm (1in) margins at the top, bottom, and sides of the page.
Page numbering is required.
Fonts & Sizes
The font used throughout the documents must conform to the following requirements.
Use one of the following type faces/sizes:
- Arial — 11pt font
- Courier New — 10pt font or larger
- Palatino Linotype — 10pt font or larger
- Computer Modern family — 11pt font or larger
A font size of less than 10 is only permitted for (text must still be readable):
- mathematical formulae or equations
- figures
- table or diagram captions
- when using a Symbol font to insert Greek letters or special characters
Additional Information
One Project Per PI
An individual may be a PI on only one active Horizon allocation request/project at a given time. Several distinct research activities can be combined in a single resource request, however, the resource request for each activity must be justified, and any allocation-size limits apply to the aggregate request.
The single-project rule is designed to minimize the effort required by PIs for submitting resource requests and the overhead to the process for reviewing those requests. While PIs may have several different funded grants that require computational support, these should be included as sub-projects within a single request.
Similarly, to minimize the effort required to gain access to Horizon, closely collaborating researchers should submit a single collaborative request rather than several individual requests. For example, a PI and associated post-doctoral researchers; investigators supported by the same funding grant; and researchers in the same lab group should consider submitting a request describing and justifying the various sub-activities. One of the collaborators is designated as the PI, and others can be designated as co-PIs.
Finally, the one project per PI restriction also applies to PIs with Horizon allocations through the NAIRR program. PIs may only have a single allocation either through this solicitation or through the NAIRR solicitation.
Acknowledgement of Support
An acknowledgement of support from the Horizon project and the National Science Foundation should appear in any publication of material, whether copyrighted or not, that describes work which benefited from access to TACC’s Horizon resource. For suggested language, see TACC Citation.
Other Requests and Feedback
The project team is interested in receiving as many excellent requests as possible, and encourages any potential investigators who wish to use the resource to not hesitate in contacting the team for additional help in preparing this request, with questions about the process, or to discuss any type of project that may not fit the structure described here. The project team also welcomes input in improving this process, and encourages feedback on both this document and the process. They can be contacted by submitting a ticket.
Submit Now
You will submit your allocation request via the Resource Allocation System.
Submission period:
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Rolling reviews will begin May 15th.