In response to an independent, external review of the Wide-Field Infrared Survey Telescope (WFIRST), NASA Associate Administrator for Science Thomas Zurbuchen is directing that the project be “reduced in scope and complexity.” The review’s findings and Zurbuchen’s conclusions will be discussed at a meeting next week of the National Academies’ Committee on Astronomy and Astrophysics (CAA).

WFIRST was recommended in the most recent astrophysics Decadal Survey as the next flagship space telescope to be built by NASA to follow after the James Webb Space Telescope (JWST), which is currently scheduled to be launched in 2019.

Decadal Surveys are produced by the National Academies of Sciences, Engineering and Medicine for each of NASA’s space and earth science disciplines. They are conducted every 10 years (a decade) to look out to the next 10 years and prioritize the most important scientific questions in that discipline and recommend missions to find answers. The astronomy and astrophysics Decadal Survey, which also recommends priorities for ground-based astronomy, is the oldest of the series, dating back to 1964. The most recent iteration, New Worlds, New Horizons (NWNH), was published in 2011.

At the time, JWST was expected to be launched in the first part of the 2010s, with WFIRST launching in 2020. Significant cost overruns and schedule delays with JWST consumed many of the resources that were intended for WFIRST, however, and development of WFIRST only began in 2016. It is currently in “Phase A” (formulation).

The launch date for JWST just slipped again, from October 2018 to March 31-June 29, 2019, although NASA insists that it has sufficient cost reserves to cover the delay and it will not impact other NASA astrophysics missions.

WFIRST is intended to study dark energy, dark matter, and search for exoplanets. It will have have a wider field of view than previous infrared space telescopes, allowing it to study much more of the universe. The Decadal Survey committee estimated its cost at $1.6 billion.

Changes to the WFIRST conceptual design began almost immediately when the National Reconnaissance Office (NRO) “gifted” two 2.4 meter space-qualified mirrors to NASA that it no longer needed.

The Decadal Survey had recommended that WFIRST have a 1.5 meter mirror, but NASA decided to accept NRO’s offer and use one of the 2.4 meter mirrors instead because it would yield better science. The NRO hardware also had improved infrared detectors.

A decision then was made to add a coronograph to the design. As with the 2.4 meter mirror, the coronagraph would produce better science, but at greater cost and added schedule risk.

A 2014 report from the National Academies chaired by Caltech’s Fiona Harrison, who now chairs the National Academies’ Space Studies Board, warned about the cost and schedule risks of adding the coronagraph because the technology is not mature. The report noted that WFIRST was chosen by the Decadal Survey committee because of its “moderate cost, low technical risk, and mature design” and cautioned that adding a coronagraph “compromises this rationale.”

Congress requires that NASA contract with the National Academies for “mid-term reviews” of each Decadal Survey half way through the relevant decade. The mid-term review for NWNH, chaired by MIT’s Jackie Hewitt, was published last year and warned NASA not to allow WFIRST to disturb the balance in NASA’s astrophysics program among large, medium and small missions. The cost for WFIRST, with the coronagraph, had grown already to $2.6-$2.8 billion, compared to $1.8 billion envisioned by NWNH (after adjusting the $1.6 billion for inflation).

The Hewitt committee recommended that NASA conduct an “independent technical, management and cost review” of the program before moving from Phase A (formulation) into Phase B (preliminary design and technology completion). If the review determined that the cost was growing at a rate that would “compromise the scientific priorities and the balanced astrophysics program” recommended in NWNH, then NASA should descope WFIRST.

NASA agreed and created the WFIRST Independent External Technical-Management-Cost [TMC] Review committee, WIETR, co-chaired by Peter Michelson from Stanford and Orlando Figueroa, who retired from NASA in 2010. He had been the head of NASA’s Mars program at headquarters and deputy director for science and technology at NASA’s Goddard Space Flight Center.

Goddard manages the JWST and WFIRST programs.

WIETR had its first meeting in August and formally submitted its report to Zurbuchen yesterday. Zurbuchen also issued a memo entitled “Next Steps for the WFIRST Program” yesterday that responds to the report.

NASA spokeswoman Felicia Chou told SpacePolicyOnline.com that the WIETR report itself is not yet public, but Zurbuchen’s memo summarizes it. She said the report will be provided to the National Academies’ CAA next week and made available on its website.

Zurbuchen’s memo reveals that the cost estimate for WFIRST is now $3.6 billion, which he says is an increase from a previous estimate of $3.2 billion. (Chou told SpacePolicyOnline.com the increase from the $2.6-2.8 billion in the Hewitt report to the $3.2 billion is because the Hewitt estimate is in constant FY2015 dollars and the $3.2 billion is in “real year dollars, covering FY2016 through FY2031 or so.”)

The memo lists a number of concerns raised by the WIETR committee that resulted in its recommendation that NASA “conduct a top-to-bottom cost-benefit assessment to balance scope, complexity, and the available resources” prior to proceeding to Phase B. It also recommended that NASA “relook at the Headquarters-to-Program governance structure to establish clarity in roles, accountability, and authority.”

Zurbuchen said in the memo that he accepts WIETR’s findings. “As a result, I believe reductions in scope and complexity are needed.”

He therefore directs Goddard to “study modifying the current WFIRST design” to reduce cost and complexity to have a cost estimate “consistent with the $3.2 billion cost target set at the beginning of Phase A.” The modified design must still be capable of achieving the science priorities set in NWNH. The results are to be presented in February 2018.

If the results conclude that WFIRST cannot meet the $3.2 billion cost target, “I will direct a follow-on study of a WFIRST mission consistent with the architecture described in the Decadal Survey.”

Zurbuchen and WIETR’s co-chars are scheduled to discuss the report with CAA on Tuesday, October 24, at 9:00 am Pacific Time (12:00 pm Eastern). The meeting will be available remotely via WebEx.

Note: This article was updated with the information about the origin of the $3.2 billion cost estimate. The title also was modified to make it clearer.