Due Date April 10th, 2025, at 8:00pm EDT

HST Call for Proposals for Cycle 33

We invite scientists to participate in Cycle 33 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 2600 orbits in this cycle, including approximately 1300 orbits for Very Small and Small Programs, 650 orbits for Medium Programs, and 650 for Large and Treasury Programs. An additional 1000 Snapshot observations and 500 Pure-Parallel observations may be allocated. Abstracts of previously accepted programs can be found on the HST proposal catalogs webpage.

Proposing Calendar and Deadlines:

• Cycle 33 Dates: November 1, 2025 – October 31, 2026
• Cycle 33 Phase I proposal deadline: Thursday, April 10, 2025 at 8:00pm EDT
• Cycle 33 Peer Review meeting: June 23 – July 3, 2025
• Cycle 33 Phase II proposal deadline: anticipated August 14, 2025 at 5:00pm EDT
• Cycle 33 Budget submission deadline: August 14, 2025 at 5:00pm EDT
• Notification of the outcome of the Phase I selection process will be sent to all proposers in late July 2025.

Where you can find assistance with proposal submissions:

• Read this Call for Proposals and The Hubble Space Telescope Primer for Cycle 33.
• Visit the STScI HST Phase I Proposal Roadmap and the HST Phase II Proposal Roadmap.
• Visit STScI’s website at http://www.stsci.edu/.
• Register (or review/check) a STScI Single Sign-On (SSO) Account.
• Contact the STScI HST Help Desk (web: https://hsthelp.stsci.edu).