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NHFP logoThe NASA Hubble Fellowship Program (NHFP) provides an opportunity for recent postdoctoral scientists to conduct independent research which contributes to any area of NASA Astrophysics. The research will be carried out at United States host institutions chosen by each fellow, subject to a limitation on the numbers of fellows that can be hosted by any one institution (see Host Institution below).

The NHFP provides salary support plus benefits for up to three years, and an additional allowance for travel and other research costs. Contingent upon NASA funding, 24 new fellowships will be awarded for 2021.

The NHFP encompasses the areas of astrophysics previously covered by the NASA Einstein, Hubble, and Sagan Fellowships. To continue the legacy of these programs, fellows will be named as Einstein, Hubble, or Sagan Fellows, depending on which of the three major NASA Astrophysics science questions most closely aligns with their proposed research.

How Does the Universe Work? - Einstein Fellows
How Did We Get Here? - Hubble Fellows
Are We Alone? - Sagan Fellows

Applications Are Closed

Applications for the 2021 NASA Hubble Fellowship Program are now closed. Applications were due by November 5, 2020, 7:00 PM EST (4:00 PM PST, 24:00 UTC)


Application Resources

Science Categories and Techniques

Frequently Asked Questions

Advice for Applicants

Visa and Benefits Information

The NHFP is administered for NASA by the Space Telescope Science Institute (STScI), in collaboration with the NASA Exoplanet Science Institute (NExScI) at the California Institute of Technology and the Chandra X-ray Center at the Smithsonian Astrophysical Observatory. Awards will be made to support each NHFP Fellow through a designated host institution.

A fellowship application consists of a research proposal and supporting documentation, as described below. Applicants must have received a PhD or equivalent doctoral-level research degree in astronomy, physics or a related discipline. The date of the PhD award should be on or after January 1, 2018, except in cases of extraordinary circumstances (see Eligibility).


Important Dates and Deadlines

  • September 8, 2020: Announcement of Opportunity issued
  • September 8, 2020: Application website open
  • November 5, 2020, 7:00 PM EST (4:00 PM PST, 24:00 UTC): Applications due
  • November 12, 2020: Letters of reference due
  • February 2021: Award offers made

Fellowship Policies

1. Eligibility

The NHFP is open to applicants of any nationality who have earned their doctoral degrees in astronomy, physics, or related disciplines on or after January 1, 2018, or who will receive their degree before September 2021.  Applicants with a PhD award date prior to January 1, 2018 may be eligible in exceptional cases (see below). Graduate-student awardees who have not yet received their doctoral degree at the time of application must present evidence of having completed all requirements for the degree before commencing their fellowships.

Eligibility of applicants for the 2021 class of NHFP Fellows may extend to those who received their PhD as early as January 1, 2017, if professional work was necessarily delayed by personal or family considerations. Such extended eligibility must be justified by emailing at least 2 weeks in advance of the application deadline.  We realize that many applicants may have had their research programs disrupted by the pandemic. We will take this into account when granting extensions for next year (applicants for the 2022 class). Extensions this year are for people whose ability to put in a successful application last year was affected by their personal or family situation.

NHFP Fellowships are open to English-speaking citizens of all nations. Qualified applicants will receive consideration without regard to race, creed, color, age, gender, gender identity or expression, sexual orientation, veteran status, disability, or national origin. Women and members of minority groups are strongly encouraged to apply.


2. Host Institution

Contingent upon availability of funding from NASA, NHFP fellowships are awarded through grants to U.S. host institutions. Applicants may select any eligible U.S. institution for carrying out their research as long as the choice is suitably justified. For the present purposes, "institution" means a separate administrative entity that offers its scientific staff a career advancement process that can lead to long-term/permanent contracts or to tenure.

Justification is particularly important in cases where the selected institution is the same one where the applicant earned his/her degree, or is the current home institution of the applicant.

A faculty member or other eligible member of the scientific staff of the host institution will serve as the faculty contact for scientific purposes and will be the Principal Investigator of the fellow's grant for administrative purposes.

To avoid an excessive concentration of fellows at any one institution, at most two new fellows will be approved for any single institution in a given year, and no more than five fellows at any single host institution, except for short periods of overlap. Thus in any given year some institutions may only be allowed to take one new fellow. For this AO, we expect that Princeton University will only be able to host one new (2021) fellow.

Applicants are asked to propose up to three prospective host institutions in order of preference. An endorsement letter from the host institution will be required for all accepted fellows. (For details see Section 5 of the Application Procedure below).

The purpose of designating second- and third-choice institutions in the application is to provide the program with flexibility should there be an oversubscription of awardees at any single institution. If a candidate does not provide second and third choices, it is possible they could be denied a fellowship if their first choice institution is not available.

It is essential that candidates for the NHFP give serious consideration to their designations of first-, second-, and third-choice host institutions before their applications are submitted. These initial designations play an important role in how fellows are matched with host institutions. In exceptional cases, it may be possible for fellows to change their mind after the award is made; however we anticipate that it would then be far harder for the fellow to get the institution of their choice given the restrictions on the number of fellows at host institutions.

In general, fellows will work full time on the research programs proposed in their applications and will be in residence at their designated host institution during the entire period of the fellowship. However, should a fellow have a compelling need to transfer to a different institution, and can present suitable justification, the STScI director may approve the request to transfer the fellowship. Transfers are subject to the policies limiting the number of fellows per institution. For more information, please contact


3. Stipend and Benefits

The initial annual stipend for a NHFP Fellow is comparable to that of other prize fellowships and is subject to annual review and adjustment. In addition, the NHFP Fellow will receive support for health insurance, relocation costs, travel, computing services, publications, and other direct research costs. No additional stipend, salary, or other remuneration may be accepted from any other appointment (such as teaching), fellowship, or similar grant during the period of the fellowship. Additional honorary named appointments intended to be linked with the title of "Hubble Fellow,” “Sagan Fellow,” or “Einstein Fellow" are similarly not allowed.

While the salary of the fellows is determined by the NHFP, benefits such as retirement, family leave, etc., depend on the rules of the host institution and whether the fellow is considered an employee or independent (stipendiary) fellow by the host institution. Prospective fellows are strongly encouraged to investigate the policies at potential host institutions before listing them on their application, as changes after acceptance can be difficult, and even impossible as host institutions reach their quota of fellows.

For more information on these issues please see the Visa and Benefits Information and Frequently Asked Questions.


4. Duration of Fellowship

Contingent upon the availability of funding, NHFP Fellowships are awarded through grants to host institutions for up to a three-year period. Funding will be provided initially for the first year of the fellowship; renewals for the second and third years will depend on satisfactory annual performance reviews, and the availability of NASA funds.


5. Status

NHFP Fellowships are analogous to prize fellowships or similar temporary postdoctoral programs at universities. They are not intended to be, nor to compete with, permanent professional career positions.

Application Procedure

1. Application Deadlines

Application Deadline:
Thursday, November 5, 2020, 7:00 PM EST (4:00 PM PST, 24:00 UTC)
Incomplete applications and/or applications received after the deadline will not be considered.

Letters of Reference Deadline:
Thursday, November 12, 2020


2. Materials Submitted Directly by the Applicant

Applicants must submit their materials via the web Application Form. These materials must include:

  • Completed Application Form
  • Curriculum vitae
  • List of publications
  • Summary of previous and current research (limited to three pages total).  Summary section references may be included in the references in the Research Proposal section.
  • Research proposal, described below (limited to five pages total including references and figures).

Please do not attach anything not listed above (reprints, preprints, cover letter, etc.) to your application.

All materials submitted must be in at least 12-point font, single spaced, and all pages should be numbered.

Non-U.S. applicants should make sure that their applications will copy successfully onto 8.5 x 11 inch (21.6 x 28 cm) paper without loss (i.e., with 1-inch margins on all sides). Please keep each file to less than 2 MB.

When you fill out the application form you will be asked to specify the science categories and techniques that best match your proposed research. This is to help us match your proposal to reviewers. For a detailed listing and more information on how they are used in the review, see Science Categories and Techniques.


3. Research Proposal

Each applicant must formulate a specific research program that is related to or motivated by NASA Astrophysics strategic goals and is compatible with the research activities of the host institution. Your application should clearly describe the relevance of your proposed research program to the scientific and/or technical goals of NASA Astrophysics – though not necessarily to specific NASA missions. Proposals to study the Solar System, Sun or Earth are not excluded, if their relevance to NASA Astrophysics is made clear. The research proposal should be no more than five pages total in length.  As a guideline, figures, references and tables should occupy about two pages. Figures and tables may be placed as needed within the proposal.


4. Letters of Reference

Applicants should arrange for letters of reference to be submitted by three individuals who are familiar with their scientific abilities and listed on the application form.  Letters must be no more than three pages in length including salutation and signature—any additional pages will be discarded.

These letters must be uploaded no later than November 12, 2020.

Applicants should emphasize to their referees that the letters must be uploaded as PDF files using the submission form by the deadline, in order for the review panelists to be able to see the letters. There is no assurance that late letters can be sent to the reviewers in time to be considered during the selection process.

Both referees and applicants will receive an email confirming the submission of each referee letter. If this email is not received, or if there are any other questions, please contact

Please note that the letters of reference are due a few days after the applications. The application deadline is November 5, 2020.


5. Endorsement Letter

Applicants who have been offered an NHFP Fellowship must arrange for a letter endorsing their fellowship to be provided to STScI by an official of the host institution. The letter of endorsement must be provided to STScI after the notification letters have been received by the successful offerees. The faculty contact at the host institution can usually help the offeree determine who the appropriate official is (e.g., the department chair, division head). The institutional endorsement is necessary to indicate that adequate facilities will be provided for the fellow. The endorsement consists of an acceptance letter signed by an authorizing official (typically the department chairperson) of the first-choice host institution. An example acceptance letter is as follows:


NASA Hubble Fellowship Program
Space Telescope Science Institute
3700 San Martin Drive

I am writing in regard to [offeree's name]'s application for an NHFP Fellowship. We have reviewed their research proposal entitled "[program title]" and are pleased to endorse it and to inform you that we will welcome them here and offer them support and facilities during the fellowship. Dr. [Faculty Contact's name] has agreed to serve as their faculty contact. Dr. [Faculty Contact's name] is authorized to act as Principal Investigator for external funding at our institution.

We acknowledge that our institutional indirect costs will be waived on the Fellowship stipend and fringe benefit.

We further acknowledge that we have read and understand the proposed change to the NHFP Host Institution Employment Policy

Sincerely yours,


The authorizing official should upload the letter per the instructions received in the email sent to the successful offeree.



Additional Information

Prospective applicants may wish to consult the Advice for Applicants page for some helpful suggestions. Requests for additional information on application procedures and supporting documents may be requested by emailing

Selection and Award of Fellowships

1. The Panel Review

The application materials and supporting documents will be reviewed by the NHFP Selection Committee between November 2020 and January 2021. Applications will be read both by experts in the area of proposed research, as well as by astrophysicists from other areas of research. Applicants are therefore advised to attempt to write a proposal that will appeal to experts and non-experts alike.

The NHFP Selection Committee makes recommendations to the STScI director in the form of a ranked list of candidates, which forms the basis on which the director grants the NASA Hubble Fellowship awards. It often happens, however, that several successful candidates have requested the same host institution. In these cases, priority is usually given to the higher-ranked candidate. The general approach taken is to place as many new fellows as possible in the host institutions of their choice, subject to: the limits on the number of fellows that can go to a given institution, the prioritized list of host institutions provided by the candidates, and the ranked list of candidates provided by the selection committee. This process can become complicated, with the decisions of one candidate affecting those of several other candidates. Thus, with the goal of filling all the fellowships in an orderly manner and avoiding last-minute decision cascades, all successful candidates are requested (and in rare cases, may be required) to make their decisions as expeditiously as possible.

Fellowship offers for 2021 will be made by early February 2021, and acceptance or refusal must be made no later than February 15, 2021. After this date additional offers may be made if any of the initial offers are not accepted.


2. Review Criteria

The primary task assigned to the NHFP Selection Committee is to identify the best science programs proposed by applicants, which can span the breadth of NASA astrophysics.

The prime criterion used by the committee in their evaluation is excellence and expected impact of the proposed research.

The committee also takes into account the following criteria:

  • Results and impact of prior research, including PhD thesis
  • Feasibility of proposed project within the fellowship timescale
  • Evidence of scientific leadership  
  • Evidence of service and public outreach activities
  • Sufficient intellectual, physical, and administrative support from the host institution and faculty advisor

Once selected, fellows are named to one of three sub-categories corresponding to NASA’s “big questions”: 

  • How does the Universe work? — Einstein Fellows
  • How did we get here? — Hubble Fellows
  • Are we alone? — Sagan Fellows

The fellowship sub-categories of Einstein, Hubble, and Sagan have no quotas and therefore do not affect acceptance into the NASA Hubble Fellowship program.


3. Commencement of the Fellowship

The NHFP Fellowship should generally begin in September 2021, but other starting dates may, in individual cases, be jointly negotiated between the fellow, the host institution, and the NHFP. All fellowships must in any case commence before the end of 2021.


4. Visa Requirements

Non-U.S. nationals who are offered awards must have valid visas, either Exchange Visitor or Immigrant Visas, for the duration of the fellowship. If an awardee applies for an Exchange Visitor Visa, the sponsorship will be under the host institution. If he/she chooses to apply for an Immigrant Visa, STScI cannot be a participant in the visa request. More information on can be found on the Visa and Benefits page.


5. NASA Hubble Fellowship Budget

NOTE: A budget is NOT submitted with the fellowship application. Detailed budget instructions are provided to successful applicants and their host institutions after the fellow accepts the offer.

After the selection process, fellows and host institutions are notified of the intent to award a NHFP Fellowship. The fellow's faculty contact will act as the Principal Investigator of the NHFP Fellowship grant. The Grants Administration Office will then request that the host institution submit a budget through the Space Telescope Grants Management System (STGMS). For information regarding program policy, including allowable costs and expenses, review the NASA Hubble Fellowship Program Policy and Budget Information. This will be updated each spring for the new year.

Note that a fellow may apply for other grants during his or her NHFP Fellowship, (e.g., HST General Observer grants), but such grants cannot include salary support. In such cases, the fellow may act as the Principal Investigator of the grant, if this is allowed by the normal rules of the host institution for scientists at the postdoctoral level.

Application Checklist

ü  You should have received your PhD on or after January 1, 2018 (see Eligibility for more details).

ü  Upload the following materials as PDF files via the NHFP Application Form, by Thursday, November 5, 2020, 7:00 PM EST (4:00 PM PST 24:00 UTC):

  • Completed Application Form (including Science Categories and Techniques)
  • Curriculum vitae
  • List of publications
  • Summary of previous and current research (limited to three pages total, including references)
  • Research Proposal (limited to five pages total including references and figures). Include relevance to NASA astrophysics.
  • Do not attach anything else (reprints, preprints, cover letter, cover sheets, etc.)

ü  Deadline for receipt of reference letters is Thursday, November 12, 2020.

ü  We recommend that you remind your referees early to send their letters by the above deadline.  

ü  Please email all correspondence to:

ü  Receipt of applications will be acknowledged by email shortly after the online submission.

ü  Applications for the NHFP Fellowships must be made using the NHFP Application Form. For technical questions related to application and/or letter submission, please contact:

ü  For questions about policies and procedures regarding the NASA Hubble Fellowship Program, please contact the Hubble Fellowship Program coordinators at


➤ Last updated: September 8, 2020

Contact the NHFP
NASA Hubble Fellowship Program