JWST Cycle 1 Guaranteed Time Observations Call for Proposals

James Webb Space Telescope (JWST) Guaranteed Time Observations (GTO) are awarded to scientists selected under AO 01-OSS-05 and through NASA-ESA-CSA agreements. JWST Cycle 1 GTO proposals were due on June 25, 2019. The approved programs are publicly available at the JWST Cycle 1 Approved GTO Programs page. 



Late breaking news

April 25, 2019: JWST Cycle 1 GTO Call re-opened and updated Cycle 1 science timeline released

July 12 2018: Following the completion of the assessment by the Independent Review Board, NASA has announced a launch date of March 30 2021 for JWST.

March 27 2018: Based on recommendations made by the JWST Standing Review Board, NASA is re-scheduling JWST’s launch window. 

March 13 2018: Successful JWST proposers will be eligible to apply for NASA High-End Computing Time. Please indicate whether you intend to apply for HEC time in the text of the Special Requirements section of the PDF submission. More information on NASA HEC Program can be found on https://www.hec.nasa.gov.

February 22 2018:  A number of GTO programs will be making some or all of their data immediately available with no exclusive access period. Those data will be available for Cycle 1 archival research programs. 



About this document

Guaranteed Time Observations (GTO) reward both individuals and teams of scientists who were selected to deliver of key hardware and software components, or technical and inter-disciplinary knowledge for JWST. The program provides a total of about 16% use of the observatory over the first 3 cycles of operation. See the section JWST Cycle 1 GTO Proposal Submission Policies for information on who is eligible to submit, observing time requirements (including overheads), data rights, restrictions on types of observations, and other policy information.

Initial versions of the GTO proposals were finalized in February 2018 prior to the original Cycle 1 GO deadline of April 6, 2018. With the revised launch schedule, the GTOs have an opportunity to revise and re-submit those proposals.  The submission process has two stages: (1) submission of APT files by June 25, 2019 - these will provide the reference targets for Cycle 1 GO proposers; (2) submission of final proposals using APT 28.1, the version used by the Cycle 1 GO proposers. The section JWST Cycle 1 GTO Proposal Submission Process describes this process in full. The relevant programs and datasets will be listed here after they have been submitted.



Important dates


Stage 1

Release of the Cycle 1 Call for GTO proposals

April 25, 2019

APT version 27.2 released

May 23, 2019

Deadline for revised GTO APT submission

June 25, 2019

Stage 2

Release of the Cycle 1 GO Call for Proposals

January 23, 2020

APT version 28.1 released (Cycle 1 reference version)early March, 2020
Final APT submission for GTO proposals
March 31, 2020

Cycle 1 GO Proposal deadline

May 1, 2020


Updated versions of the Director's Discretionary Time Early Release Science (DD-ERS) programs were submitted following the GTO schedule.



GTO proposal submission

Teams should submit revised proposals using the Astronomer's Proposal Tool (APT). APT 27.2 will be released as part of PPS 14.7 on May 23, 2019. Proposals should be completed by June 25, 2019. APT 27.2 does not include the final timing model that will be used for Cycle 1, so GTO proposers will not be held to strict time limits. GTOs will have an opportunity to adjust and finalize their proposals prior to the Cycle 1 GO deadline.



Who's responsible

Members of the Science Mission Office at STScI are responsible for the oversight of the JWST science program selection process. The members involved include Neill Reid (Associate Director for Science), Alessandra Aloisi (Head, Science Mission Office), Louis-Gregory Strolger, Amaya Moro-Martin, and Technical Manager Brett Blacker.



Where to get help

Submit questions to the JWST helpdesk at jwsthelp.stsci.edu.  Consult JWST documentation at jwst-docs.stsci.edu, and see stsci.edu/jwst for additional tools and resources. 



Download PDF

JWST Cycle 1 GTO Call for Proposals, 06 Jan 2017 [PDF]




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Originally published