NASA announced today that the launch date for the James Webb Space Telescope (JWST) has been delayed yet again, this time to March 30, 2021. It is the latest setback for the successor to the Hubble Space Telescope, which was rebaselined in 2011 due to previous cost overruns and schedule delays. At that time, NASA vowed it would launch in October 2018, but that date slipped to 2019 to 2020 and now to 2021. The cost has also grown and will breach the $8 billion development cap set by Congress, meaning it will have to be reauthorized.

The announcement comes in the wake of a report from an Independent Review Board (IRB) chaired by retired government and industry executive Tom Young. Young is a former Director of NASA’s Goddard Space Flight Center who went on to become President of Martin Marietta until it merged with Lockheed to form Lockheed Martin. He is often called upon to chair studies of government space programs to determine why they went awry.

JWST has a two-decade history replete with repeated cost overruns and schedule delays. In 2010, exasperated by another overrrun and delay, then-Senator Barbara Mikulski demanded an independent review. Chaired by JPL’s John Casani, it primarily faulted NASA management. NASA restructured the program and in 2011 assured Congress that development would cost no more than $8 billion (not including operations) with launch in October 2018.

Congress set the $8 billion for development in law as a cap. Pursuant to the 2005 NASA Authorization Act, if a NASA project exceeds certain cost thresholds, NASA must report it to Congress, which then must reauthorize the program.

The program appeared to be on track until September 2017 when NASA announced that integration problems at the prime contractor, Northrop Grumman, would delay the launch to March-June 2019. Then, in March 2018, another delay was announced, to May 2020.

At that point NASA commissioned the IRB to provide an assessment of whether the May 2020 date could be met. Today NASA released the IRB report and NASA’s response to it.

Among the conclusions is that the telescope will not be ready for launch until March 2021. Based on that schedule, NASA concluded that the development cost will rise to $8.803 billion, breaching the cost cap by $800 million, or 10 percent. The life cycle cost for the project, including operations, will now be $9.663 billion instead of $8.835 billion.

Those costs do not include launch. The European Space Agency (ESA) is launching JWST as part of a cooperative agreement with NASA at no cost to the United States. Canada is also a partner in the project.

At a media teleconference today, NASA officials repeated the mantra “Webb is worth the wait” because of the exciting scientific discoveries it will produce. In a video message to NASA employees, NASA Administrator Jim Bridenstine said the agency is committed to the project.

Because it breached the cost cap, Congress now must reauthorize the project. The chairman of the House Science, Space, and Technology Committee, Rep. Lamar Smith (R-TX), said in an emailed statement that his committee will review the IRB report in detail and hold a hearing next month with Young, Bridenstine, and Northrop Grumman’s Wes Bush to “ensure accountability and efficiency in the JWST project.”

Smith’s Democratic counterpart, Rep, Eddie Bernice Johnson (D-TX), ranking member of the committee, said in an emailed statement that she expects NASA and Northrop Grumman to “take the IRB recommendations to heart so that Congress can have confidence that the taxpayer dollars invested in this project are not wasted or adversely impact the rest of NASA’s science programs. That said, I strongly support completion of JWST…”

Sen. Bill Nelson (D-FL), the top Democrat on the Senate Commerce, Science, and Transportation Committee, also expressed continued support in an emailed statement. “While I am deeply disappointed … I believe the discoveries we will get” from JWST “will be worth the cost of completing the mission.”

At today’s media teleconference, Young said that the IRB identified five factors that led to the 29-month schedule delay from October 2018 to March 2021 and resulting cost increase:

Human error

Embedded problems

Lack of experience, such as in building the spacecraft’s sunshield

Excessive optimism

System complexity

The IRB was composed of an illustrious group of aerospace engineers and space scientists with extensive experience in managing space projects. Young said they were unanimous in supporting continuation of the project because of its “awesome scientific potential.”

That said, Young explained that the March 2021 launch date is an “80/20” estimate, meaning it has an 80 percent probability of happening. It assumes NASA will “rigorously implement” the IRB’s recommendations, especially with regard to human error and embedded problems.

Human errors cannot be eliminated, Young noted, but they must be minimized. He cited as an example the cleaning of JWST’s thrusters with the wrong solvent, ruining them. They had to be refurbished, causing a 9-month delay. The entire problem could have been avoided if only technicians had checked with the thruster vendor to ask what solvent to use. In the future, Young insisted, there must be a safety net of testing and inspection to catch such errors more quickly.

Another problem was the incorrect installation of fasteners on the sunshield. When it went through acoustic testing, about 70 of them fell off. Fixing that took 6 months and two of the fasteners have not been found yet and still may be in the telescope. NASA Science Mission Directorate Associate Administrator Thomas Zurbuchen said they are doing a detailed inventory and will remain focused on the probem until they are 100 percent certain all have been located.

Zurbuchen pointed to all that has been accomplished so far. The scientific instruments have been built and tested. The spacecraft has been built. The issues are now in the integration of the instruments and the spacecraft and testing them to ensure everything is working perfectly before launch. “We have a plan” going forward, and “Webb is worth the wait.”

Asked about lessons learned, especially whether NASA took on too much technical risk in deciding to build JWST, Zurbuchen said that is a question that must be asked, but taking big risks to get big scientific rewards is what NASA does.

Zurbuchen and NASA Associate Administrator Steve Jurczyk said the agency accepts and is implementing the IRB recommendations. Jurczyk called JWST a “critical pillar” of U.S. astronomy and Zurbuchen characterized it as NASA’s highest scientific priority.

Jurczyk said the agency will need to request $837 million more than projected for JWST in the outyears (FY2020 and FY2021 presumably) in the President’s FY2019 budget request to cover the overrun.

The ball is now in Congress’s court. With all that has been spent already, it seems unlikely that it will refuse to reauthorize JWST or provide the additional funds.

The question is what impact this will have on other NASA astrophysics programs, especially the Wide-Field Infrared Survey Telescope (WFIRST). In the 2010 astronomy and astrophysics Decadal Survey from the National Academies, the scientific community recommended WFIRST as the follow-on to JWST, just as JWST is the follow-on to Hubble.

Eight years later, WFIRST is still in the starting blocks because JWST consumed the resources that were meant for it. Now the Trump Administration wants to cancel WFIRST so it can use the money for other agency priorities, especially human spaceflight. So far, the House and Senate Appropriations Committees have rejected that proposal and retained funding for WFIRST — the Senate more enthusiastically than the House — but now that JWST will require an additional $800 million in the near future, WFIRST’s future seems more precarious.

Note: This article has been updated.