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Hubble Space Telescope
Multi-Cycle Treasury (MCT) Program Information


We invite scientists to participate in proposing for Multi-Cycle Treasury programs using 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). Up to 750 orbits per cycle, starting in Cycle 18, will be available for MCT Programs. The intent is to provide astronomers with the opportunity to tackle key scientific questions that cannot be fully addressed through the standard time allocation process.

Release Notice

NASA and The Space Telescope Science Institute (STScI) are pleased to announce this Multi-Cycle Treasury Program Call for Proposals for Hubble Space Telescope (HST) Observations. 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.
This solicitation for proposals will be open through Wednesday November 18, 2009 5:00pm EST. The Astronomer's Proposal Tools (APT) version 17.4.3, which is required for Phase I Proposal Submission, is the current release and is valid for use. The MCT TAC will meet in Baltimore in early January 2010. The results will be announced to the community in late-January, 6-7 weeks before the Cycle 18 Phase I deadline.

Late Breaking News

  • January 31, 2010: MCT Program Information
    Three programs have been accepted for implementation in the following science areas: galaxy clusters; resolved stellar populations in nearby galaxies; and deep infrared field/high-redshift supernovae. The information is posted at:
  • November 19, 2009: MCT Submission Information
    Thirty-nine proposals requesting a total of 26,801 orbits were submitted in response to the MCT Call. This represents an oversubscription of at least 12:1. The proposals are being distributed to the MCT TAC, who will meet in Baltimore in early January 2010. The results of their deliberations will be announced to the community by January 20th, and unsuccessful proposers will have the opportunity to recast their programs for HST Cycle 18 (Phase I deadline, February 26 2010).
  • November 13, 2009: MCT Phase I Deadline Clarification on Time
    It was brought to our attention that we had 2 different times for the Multi-Cycle Treasury Program Phase I Proposal Deadline. On our announcement page and the email announcement that was sent out on August 13th, 2009, we listed the Deadline as 5:00pm. However, the Call for Proposals lists the Deadline as 8:00 pm. We will set the formal deadline at 8:00 pm on Wednesday November 18, 2009.
  • November 12, 2009: APT Multi-Cycle Treasury Button
    Please ensure that the "Multi-Cycle Treasury" flag has been checked on your Proposal Information page.
    Please note that you are only required to enter a representative sampling of targets and observations. (See sections 8.15 and 8.16 of the MCT Call.)
  • November 02, 2009: APT 17.5
    APT 17.5 contains a large number of infrastructure and look-and-feel changes. If you are currently using APT 17.4.3 to work on a Multi Cycle proposal, there is No need to take this release before you submit your proposal. But there is a beta Phase II mosaic capability that you may find useful for planning purposes if you are proposing a complex mosaic for your Multi Cycle proposal. (It has more functionality than the Phase I mosaic capability.) To preview what the new mosaic tool can do watch the 8 minute training movie:
    We would be delighted to answer your questions and receive your feedback on this capability. Just write to
  • October 28, 2009: Updated ETCs
    The Exposure Time Calculators (ETCs) have been updated to include the latest throughput information available from SMOV. In some cases, these updates can lead to different exposure time estimates than those provided by earlier versions of the ETCs, so observers are encouraged to use the latest ETCs (v18.0) when preparing their MCTP proposals.
  • October 04, 2009: Preliminary Characterization of the Post-Launch Line Spread Function of COS
    The COS team has released an Instrument Science Report (ISR) characterizing the Post-launch Line Spread Function of the COS. The ISR can be found at:
  • September 29, 2009: Performance of the STIS
    The STIS team has released a STAN detailing the performance of STIS since the repair during SM4. Updated information can be found at:
  • September 15, 2009: COS Line Spread Function (LSF) and Performance of the ACS-R
    Updated information on the COS LSF can be found at:
    The ACS team has released a STAN detailing the performance of ACS-R, which can be found at:
  • September 11, 2009: WFC3 Characterization
    Updated science performance characteristics for WFC3 are available from the WFC3 team at the WFC3 page: Similar updated information will become available for other instruments in the near future.
  • September 10, 2009: ERO and ERS Data Products
    The SM4 Early Release Observations (ERO) and Early Release Science (ERS) Observations have been released and the data products are available at:
  • August 13, 2009: MCTP Call for Proposals is now available below.
    The Current APT interface can only handle 1 PI. Please list any additional PIs as the first CoI(s) in the CoI interface and please use the Management Plan section to annotate and describe the roles of the Multiple PIs as well as CoIs. You can also put "(Co-PI)" in the CoIs last name after you have selected it from the APT Address/Name locator tool.
  • August 08, 2009: Instrument handbooks will not be updated for this MCTP Call for Proposals Release. However, instrument updates will be made available shortly after the Early Release Observations from Servicing Mission 4 have become public, which is expected to occur in early September. Further updates will be made on a regular basis.
  • August 07, 2009: NICMOS will not be available for Multi-Cycle Treasury programs. While it may be possible to restore NICMOS to service soon, observatory power constraints require that the instrument be used only during certain times of the year, thereby making it difficult to reliably schedule very large programs spread over multiple cycles.


  • The MCTP Call for Proposals (Get the CP as: PDF [US Letter Size], or as HTML)
  • The Current Cycle Call for Proposals describes the policies and procedures for submitting a HST Phase I proposal. Get the CP as: PDF [US Letter Size], PDF [A4 Size], or as HTML.
  • The Primer provides an introductory overview of the Hubble Space Telescope and explains how to calculate the appropriate number of orbits for an observing proposal. Get the Primer as: PDF [US Letter Size], PDF [A4 Size], or as HTML.
  • The MCTP Review Committee Report
  • HST Phase I Roadmap A step-by-step guide to proposing and submitting an HST proposal.
  • Science Justification Templates for MCTP Programs.

    The Proposal Process

    The MCT program provides an opportunity for the HST community to address high impact scientific questions that require observations on a scale that cannot be accommodated within the standard time allocation process.
    MCT programs are defined by the following characteristics:
    • MCT programs must require at least 450 orbits and can request more than 1,000 orbits
    • Up to 500 orbits of GO observations and 250 orbits of Director's Discretionary time will be available in Cycles 18 and 19. Proposers may request additional orbits in future cycles, if scientifically justified.
    • MCT programs will only be scheduled as GO observations.
    • MCT Programs must clearly specify why the science goals cannot be achieved through the standard TAC process.
    • MCT Programs may enable a broad variety of compelling scientific investigations; they may also focus on one specific problem.
    • MCT Programs may have more than one Principal Investigator; one PI must be listed as the designated contact.

    MCT proposals will be assessed by a dedicated Time Allocation Committee. There will be no restriction or pre-selection of science topics. The MCT TAC may recommend rejection of all proposals if, in their judgment, none require resources beyond those available through the standard TAC process.
    Calls for MCT Programs will not be issued on an annual basis. A future call may be issued, depending on the response to the current call and the future health of HST. However, the community should be aware that this may be the only call for proposals of this type.

MCT Proposal Schedule

Proposers should be aware that HST instruments are currently going through the Science Mission Orbital Verification (SMOV) process. The dates specified below are contingent on the completion of SMOV on an appropriate schedule.
Prospective proposers should consult the MCT proposal page (this page): for updates and late breaking news.

Notice of Intent

In preparation for this call, we ask that prospective Principal Investigators submit a non-binding Notice of Intent (NOI). The NOI should include the following information:
  • Name of the Principal Investigator(s)
  • Proposal title and short abstract
  • Names of known co-Investigators

Submission of an NOI is not required, but will provide a means of our assessing the likely number of proposals and the potential subject areas, information that will be useful in constituting the MCT TAC. NOIs should be submitted by e-mail to by August 07, 2009.

Further Information

Questions can be addressed to the STScI Help Desk (email:; phone: 410-338-1082).

Release Documents

    The Call for Proposals describes the policies and procedures for submitting a HST Phase I proposal. Go to the CP.

    The Primer provides an introductory overview of the Hubble Space Telescope and explains how to calculate the appropriate number of orbits for an observing proposal. Go to the Primer.

    Science Justification Templates for Cycle 27 HST Phase I

  • Full Set of HST Documentation

HST Phase I Roadmap

    The Roadmap is a step-by-step guide to proposing and submitting an HST proposal. Download APT here.

DD Time

Up to 10% of the available HST observing time may be reserved for Director's Discretionary (DD) allocation.

Mid-Cycle Proposals

Up to 200 orbits per cycle will be available for Mid-Cycle GO programs. Mid-Cycle programs were initiated in Cycle 23 to provide the community with an opportunity to propose for in-cycle observations of recently-discovered, non-variable objects. As such, they complement Director’s Discretionary programs, which target unexpected transient phenomena and time-critical observations..

Special Programs from Past Cycles

Status of Current and Past Programs:

Past Proposal Opportunities