STScI solicits proposals for HST Observing, Archival, and Theoretical Research. The full details are made available through two documents, the Call for Proposals, and the HST Primer. Downloadable PDF collections of these articles are provided as a courtesy, made available and updated when feasible. The online documentation is the authority, and will be updated with the latest information.

Late Breaking News

December 18, 2025:
- APT Released: APT version 2025.7.2 is now available. Any HST proposals started in earlier APT versions should now be edited and submitted in this version.
January 16, 2026:
- Word templates updated: Make sure to use the most recent version of the PDF attachment templates. Using an older template could cause the proposal to be disqualified.

Announcement

Release Notice: December 12, 2025

We are pleased to announce the Cycle 34 Call for Proposals for Hubble Space Telescope (HST) observations and funding for archival research programs. Participation in this program is open to all categories of organizations, both domestic and foreign, including educational institutions, profit and nonprofit organizations, NASA Centers, and other Government agencies. Cycle 34 will extend from November 1, 2026 - October 31, 2027. We will accept proposals for the following instruments: ACS, COS, FGS, STIS, and WFC3. This solicitation for proposals will be open through Thursday, April 16, 2026 at 8:00pm EDT. The Astronomer's Proposal Tool (APT), which is required for Phase I Proposal Submission, will be made available for Cycle 34 Phase I use in early 2026. Results of the selection will be announced by late July 2026. Questions can be addressed to the STScI HST Help Desk (https://hsthelp.stsci.edu).

Welcome

We invite scientists to participate in Cycle 34 of the Hubble Space Telescope (HST). The telescope and its instruments were built under the auspices of the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). Management of HST’s scientific program is carried out by the Space Telescope Science Institute (STScI). We anticipate allocating up to 2700 orbits in this cycle, including approximately 1350 orbits for Very Small and Small Programs, 675 orbits for Medium Programs, and 675 for Large and Treasury Programs. An additional 1500 Snapshot observations and 500 Pure-Parallel observations may be allocated. Abstracts of previously accepted programs can be found on the HST proposal catalogs webpage.

This document establishes the goals, requirements, and policies for General Observer (GO), Archival Research (AR), and Snapshot (SNAP) programs in Cycle 34. The table of contents for the web version of this document is on the right side of the page. The top right panel "On this Page" gives the contents of the current page. The bottom right panel contains the directory structure or tree of the "HST Proposal Opportunities and Science Policies" pages, and contains links that can take you to any page from any other page (click the arrow to expand the entire table of contents under "Hubble Space Telescope Call for Proposals for Cycle 34") within this directory. The tabs and drop down menus at the top, direct you to other sections of the HST User Documentation (e.g., "Instrument Handbooks").

Proposing Calendar and Deadlines

Cycle 34 Dates: November 1, 2026 - October 31, 2027

Cycle 34 Phase I proposal deadline: Thursday, April 16, 2026 at 8:00pm EDT

Cycle 34 Peer Review meeting: June 22 - July 1, 2026

Cycle 34 Phase II proposal deadline: anticipated August 13, 2026 at 5:00pm EDT

Cycle 34 Budget submission deadline: end-August 2026, for planning purposes only

Notification of the outcome of the Phase I selection process will be sent to all proposers in late July 2026.

What's New for Cycle 34

See HST New and Important Features.

Important Resources

Read this Call for Proposals, which summarizes the policies and procedures for proposing in the current cycle of HST observing, including requests for research funding on archival HST data.
The Hubble Space Telescope Primer for Cycle 34 provides an overview of the Hubble Space Telescope, with basic information about the telescope operations, instrument capabilities, and technical aspects of the proposal preparation process.
Read the STScI HST Phase I Proposal Roadmap and the HST Phase II Proposal Roadmap for guidance on your Phase I and Phase II, respectively.
Templates for the Proposal PDF attachment can be found on the HST Preparation of the PDF Attachment page.
Visit STScI’s website at http://www.stsci.edu/ for more information about STScI.
Register, verify, or update your STScI Single Sign-On (SSO) Account, needed for submitting your proposal and downloading proprietary data.
For any concerns or an overview of how HST and JWST overlap, see Guidelines for Proposals where JWST and HST Overlap in Capabilities.
Contact the STScI HST Help Desk (https://hsthelp.stsci.edu) to submit questions, concerns, or feedback on HST instruments, software, or policies.

Who's Responsible

The HST Call for Proposals and related materials for Cycle 34 were edited by Amy Jones. The Associate Director for Science, Mercedes López-Morales, and the Science Policy Division (SPD) at STScI are responsible for the oversight of the HST science program selection process. SPD members include Laura Watkins (SPD Head), Claus Leitherer (Hubble Science Policy Lead), Molly Peeples (Cross-Mission Policy Scientist), Daniel D'Orazio, Rebecca Levy, Joshua Lothringer, Amaya Moro-Martín, Nikolay Nikolov, Lou Strolger, and Technical Manager Aleksandra Hamanowicz. Neill Reid (Multi-Mission Project Scientist) participates in an advisory capacity.

Download the PDF

This PDF is provided as a courtesy, made available and updated when feasible. The online documentation is the authority, and will be updated with the latest information.

Next: HST New and Important Features

Hubble Space Telescope Call for Proposals for Cycle 34