NASA Hubble Operational Paradigm Change Review and Hubble Observations

NASA is conducting a review of Hubble and Chandra operations with a view to reducing costs. The review is driven by financial pressures within the overall NASA Astrophysics Budget, not by any deficiencies in Hubble science or operational performance. The Hubble budget covers the following items:

  • Mission operations at GSFC and STScI, including:
    • routine operations, flight software, anomaly response;
    • telescope & instrument operations, commanding, health and safety;
    • user support, planning and scheduling
    • instrument calibration, data pipeline maintenance, archives, tools, high-level science products (HLSPs);
    • Telescope Allocation Committee (TAC) and grant administration;
    • outreach and engagement;
  • Multi-year General Observer (GO) and Archival Research (AR) grants for the US community;
  • The NASA Hubble-Einstein-Sagan Fellowship Program.

The Hubble budget has been ~$98.3 million since 2012. The FY25 President's Budget Request is $88.9 million, including ~$8 million for the Fellowship program. This amounts to a ~20% reduction.

The STScI and GSFC Hubble Team made a presentation to the Operational Paradigm Change Review (OPCR) committee on May 8, 2024, where we outlined a number of options for continued operations under the reduced FY25 budget.

Guiding Criteria and Likely Outcomes

Our proposals were tied to the following key criteria:

  • Maintain operations, Hubble's unique UV/optical capabilities & grant support;
  • Balance between continued science operations and community needs for science;
  • Maintain support for a diverse user community without building in disparity.

NASA has not yet provided feedback. However, budget reductions will result in significant impacts to Hubble operations, including a reduced suite of instruments. In particular, it is likely that we will have to:

  • Halt WFC3/IR operations;
  • Halt ACS/WFC operations;
  • Halt support for creating and hosting high-level science products;
  • Reduce the level of grant funding to the community;
  • Reduce the level of support for public outreach;
  • Consider possible impacts for other instruments depending on the scale of budget reductions.

We will not take any actions to until we receive formal instructions from NASA.

Observing Impacts

  • We will aim to complete programs from Cycle 31 and earlier cycles as originally submitted.
  • For Cycle 32 programs, where possible we will consider the following mitigations:
    • ACS/WFC observations will be considered for transfer to WFC3/UVIS;
    • Programs with a component of WFC3-IR observations may be considered for transfer to JWST NIRCam.
  • Some Cycle 32 programs may no longer be viable and will have to be cancelled.

Further information on the current situation can be found in presentations to the STUC on April 3, 2024 and from the June 26-27, 2024 meeting.

We will keep program investigators and the community informed as we learn more from NASA.

Community members with questions should direct them to

Frequently Asked Questions

Has STScI considered continuing to operate instruments in a partially or unsupported mode of operations?

Yes; we have chosen not to follow that approach since that would be inequitable in placing new and less experienced HST users at a disadvantage in implementing their program. Additionally, much of HST science depends on high fidelity calibration of the data, and that will no longer be possible even under partial support. The fidelity of the data impacts current investigations and the long-term legacy value of the HST archive, and unsupported observations undermine both.

What is the rationale for de-prioritising WFC3-IR and ACS/WFC?

All of HST’s instrument continue to produce first rate science; the decision to halt observations with a subset is based on the resources available. STScI has prioritized the unique UV capabilities of Hubble. ACS/WFC and WFC3-IR are redundant to some extent, since ACS/WFC has similar capabilities to WFC3-UVIS and WFC3-IR overlaps with JWST capabilities.

What will be the level of community grant funding for Cycle 32?

That depends on the level of budget cuts from NASA. STScI has continued grant-funding obligations to programs from past HST cycles, and that will also affect the level of funding available for new programs.

When will the results of the OPCR be known?

NASA indicated at the summer AAS (June 10) that it plans to hold a Town Hall meeting within ~2 months of that meeting.

Is the OPCR related to Hubble’s move to Reduced Gyro Mode?

No: Hubble continues to produce fore-front science under RGM; the budget reductions from the OPCR are solely the result of financial pressures with NASA Astrophysics.

If observations with WFC3-IR or ACS/WFC are halted, can they be re-started quickly if funding becomes available?

No; STScI will have re-assigned personnel, and there may be contractual requirements that would preclude re-hiring new staff to support those instruments.

What are the implications of halting support for Higher-Level Science Products? Does this affect all HLSPs?

The extent of the impact depends on the budget reductions. At the very least, we expect that it will not be possible to create and support new HLSPs, whether from in-house instrument team work or supplied externally by community programs. The impact on current HLSP holdings remains unclear.

I received an AR notification email. Does that mean that my program was approved pending budget decisions?

No; All AR proposers received the same notification. We will provide further information when it becomes available from NASA.