Casey DreierMar 27, 2018

JWST heads once more unto the breach, dear friends

The James Webb Space Telescope—the successor to the Hubble Space Telescope and the space agency's largest science mission ever—will miss its target launch date and will likely cost more money than expected, NASA announced today.

This is not the first time this has happened to Webb. Originally estimated to cost $3.5 billion, the project was restructured in 2010 with a new cost estimate of $8 billion for development and another $800 million for operations. While it survived a near-death experience after angry congressional appropriators proposed to cancel the project, every appropriation since has stated that "the formulation and development costs for the James Webb Space Telescope shall not exceed $8,000,000,000."

Despite these emphatic congressional "shall nots," it appears James Webb shall. 

It is very unlikely that Congress will cancel this mission. All of the hardware is built—it just needs to be pieced together and tested. But this phase of spacecraft construction (Phase D in NASA management parlance) almost always reveals hidden complexities and unexpected issues. Projects pad their schedules and budgets to accommodate these unknown but predictable problems, but the larger the project, the more complex the problems, and the more difficult the fix. One small issue can cause a cascade of delays, each causing more delays, which themselves delay other goals, and so on. In other words, James Webb's problems are "non-linear."

Because of this, NASA does not yet know exactly how much more money is needed to get the telescope ready for launch. The May 2020 date is a best guess based on current information. It could be later. We will know more by June, when NASA will submit its new plan to Congress.

Lee Billings at Scientific American has a good article highlighting some of the implications for the Astrophysics community given this new delay. But I want to focus on one major one: the future of WFIRST, the follow-on space telescope after Webb. 


The Wide-Field Infrared Survey Telescope (WFIRST) is the top-priority astrophysics mission after the James Webb Space Telescope. It would use a Hubble-sized primary mirror to capture broad swaths of the sky in the infrared spectrum, and potentially unleash great new insights into dark energy and other important cosmological questions.

But this project was already facing significant programmatic headwinds after its own bulging cost estimates (to $3.8 billion), which moved the White House to propose to cancel the mission in order to shift funding toward its human lunar exploration initiative.

Astronomers are rallying to protect WFIRST by petitioning Congress to restore funding in the 2019 budget cycle, and for the mission to find cost reductions to make it more affordable.

Congress had already made a positive statement by providing $150 million for WFIRST in the  final fiscal year 2018 budget deal, which came after the proposal to cancel the mission. Along with the legislation, the official report on the spending bill stated that congress "rejects the cancellation of scientific priorities recommended by the National Academy of Sciences decadal survey process," a clear sign of support for the decadal priority WFIRST project.

As Thomas Zurbuchen, the Associate Administrator of NASA's science portfolio stated today, WFIRST is not another James Webb. He said comparing the two space telescopes is like comparing a Ferrari and a Chevy Malibu—they're both cars, but one is substantially more complex and expensive than the other.

To emphasize this distinction, he showed this comparison of the two projects at KDP-B, a project management goalpost that signifies the end of the planning phase before the project locks in a design and a formal cost estimate. Even without understanding all of the details, one can tell that WFIRST is substantially simpler than James Webb, requiring far fewer new technologies.

Webb vs. WFIRST risks
Webb vs. WFIRST risks Image: NASA

But here's the rub: even if WFIRST continues, its funding could be severely restricted by James Webb's cost overruns. As you can see in the chart below, the WFIRST project was counting on funding opening up as the James Webb project wound down. This "wedge" of new funding would allow WFIRST to continue even under a flat budget over the next few years, as is predicted by the White House. WFIRST needs something like $350 million in 2019 to continue as planned for a mid-2020s launch. James Webb was originally planned to decrease by $250 million in 2019, making that additional funding lift for WFIRST much easier.

Astrophysics major projects
Astrophysics major projects NASA’s Astrophysics division budget, with major projects.Image: NASA

While we still don't know what Webb needs to finish, we know it won't be $0. The comparatively svelte InSight Mars lander added approximately $160 million to its mission cost after it missed a Mars launch window two years ago, on top of a budget of $675 million. Bigger projects like James Webb will have comparatively larger overruns, and even if it can dip into its planned operations budgets to soften the overall blow, the consequences will likely befall WFIRST, which is already teetering on the edge of cancellation. 

There are a few paths forward:

  • Congress could fund both WFIRST and James Webb, and increase funding to NASA overall. This is not out of the question, as overall funding caps have been relaxed for 2019, making it easier to accommodate bumps in the road (see the bonus $350 million that provided a second mobile launcher for SLS in the 2018 budget as an example).
  • WFIRST could be delayed into the future, minimizing the funding needs in 2019 but likely increasing the overall cost of the project in the long run.
  • WFIRST could be cancelled as Congress loses its appetite for larger science missions after being burned by James Webb.

And even one more aspect to consider: should the House of Representatives flip to Democratic control in the November elections, previous agreements on spending could be made moot by an ideological standoff between the parties. It's possible that no budget could be passed in 2019 and all programs would continue on a continuing resolution. This would have the effect of keeping WFIRST on life support, as a CR would prevent the cancellation of the project.

Until we know more, WFIRST continues to move forward with $150 million in 2018, waiting, like to rest of us, to learn more about the fate of James Webb.

The Time is Now.

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