Hertz Seeks to Calm Worries About Impact of Potential JWST Overrun

Hertz Seeks to Calm Worries About Impact of Potential JWST Overrun

NASA Astrophysics Division Director Paul Hertz today sought to calm concerns about the impact on the astrophysics program if the James Webb Space Telescope (JWST) exceeds its $8 billion budget cap.  Arguing that it might not breach the cap at all, Hertz said the impact on the rest of the astrophysics program might not be felt for years since JWST funding budgeted for operations can be repurposed to solve the current problems.  He also said that it is “not obvious” that NASA’s proposal to delay the next Decadal Survey for astrophysics will be accepted.

Paul Hertz, Director, Astrophysics Division, NASA Science Mission Directorate. Credit: NASA

Hertz spoke to NASA’s Astrophysics Advisory Committee for more than two hours about the broad range of programs within the astrophysics portfolio.  Following are some of the key points that arose regarding JWST and plans for the next astrophysics Decadal Survey.


JWST’s October 2018 launch date was delayed until March-June 2019 last fall, and on March 27 NASA announced a further delay until at least May 2020. That date was rated by JWST’s Standing Review Board (SRB) as having a 70 percent probability of occurring.  NASA appointed an Independent Review Board (IRB) chaired by Tom Young to make an external assessment of the program’s status. The report is due to NASA at the end of May.  Hertz characterized the IRB’s task as ensuring that “we’re not cutting corners just to make a launch date or meet a cost cap.”

That cost cap, which is set in law, is $8 billion for development (it does not include operations).  NASA has spent $7.3 billion so far.  Hertz said it will be some time before the cap is reached, and even with the recently announced delays, the program may not breach the cap at all.  All the hardware is built.  What remains is “work” — the labor to complete Integration and Testing (INT).

Hertz says he looks at program costs three ways:  the lifecycle cost through 5 years of operations, to which NASA is currently committed to $8.875 billion; the cost through launch and commissioning, which is the $8 billion cap; and how much JWST needs on a year to year basis.

The life cycle cost certainly will grow because the launch will be delayed and therefore the operational period will extend through additional years, he said.  The cost to commission the telescope probably will grow because INT will be taking place in years when the telescope should have been in operations.  But on an annual basis, which Hertz argues has the main impact on other astrophysics projects, the impact should be minimal because money that was budgeted for operations can be reallocated to INT.  The financial impact on the astrophysics program will not be felt until the 2030s, he argued, when the telescope is operating beyond its planned budget horizon.

The SRB and IRB reviews are providing input to NASA’s assessment of what it will take to complete the program.  “We don’t have the final numbers yet,” Hertz said, but what he is hearing informally suggests that “they are not scary numbers.”  The program has the money it needs in the FY2019 budget request.  The first year for which additional funds might be needed is FY2020.  “I’m not panicking over the impact,” which he expects to be “modest on a year by year basis.”

Next Astrophysics Decadal Survey

NASA Science Mission Directorate head Thomas Zurbuchen is raising the possibility of delaying the next astrophysics Decadal Survey because of the JWST launch delay and uncertainty about the Wide-Field Infrared Survey Telescope (WFIRST).  Decadal Surveys are conducted every 10 years by the National Academies of Sciences, Engineering, and Medicine to identify the key science questions and recommend missions to answer them for NASA’s science programs.

JWST was the top priority for a large space-based mission in the 2000 astrophysics Decadal Survey.  WFIRST was the top priority in the 2010 Decadal Survey, but its implementation was delayed for several years because of cost overruns on JWST.  The Trump Administration has proposed cancelling it in the FY2019 budget request, but NASA is proceeding with the program in FY2018 as planned until Congress makes a decision on the program’s fate.

The next astrophysics Decadal Survey is scheduled to begin soon and be completed in 2020.  That schedule would have worked well if JWST launched in 2018 as planned and WFIRST’s development was underway.  With JWST’s launch delayed until at least 2020 and WFIRST’s future uncertain, the question is whether to wait an extra two years to do the Decadal.

One challenge is that the astrophysics Decadal sets priorities not only for NASA’s space-based telescopes, but for ground-based programs at the National Science Foundation (NSF) and for astrophysics programs in the Department of Energy’s (DOE’s) High Energy Physics program.

Hertz said NASA, the Academies, NSF and DOE are discussing the matter and “it is not obvious to me” that the decision will be to delay.

NASA is funding studies of four potential space-based telescopes for consideration by the upcoming Decadal committee.  Asked if NASA is planning any changes, Hertz said he has not thought that through since “no decision has been made and I am not in a position to predict with high probability” that the Decadal will be postponed.


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