NASA struggling to get James Webb Space Telescope across the finish line
This article originally appeared in the April 9, 2018 issue of SpaceNews magazine.
On the evening of Feb. 2, a C-5 plane landed at Los Angeles International Airport, having taken off a few hours earlier from Ellington Field in Houston. A truck unloaded its contents, a customized cargo container called the Space Telescope Transporter for Air, Road and Sea (STTARS), and drove it several kilometers away to the sprawling Space Park campus of Northrop Grumman.
Inside STTARS was the optical telescope assembly for the James Webb Space Telescope, including its giant segmented mirror and suite of instruments, which had recently completed thermal vacuum testing at the Johnson Space Center. The telescope part of JWST was now, for the first time, in the same clean room as its spacecraft bus and sunshield, ready to put together — if all went according to plan.
But, with JWST, not everything goes according to plan. “With all the flight hardware 100 percent complete, we’re approaching the finish line for launch readiness,” said Thomas Zurbuchen, NASA associate administrator for science. “However, it looks like we have a ways to go before we cross that finish line.”
Zurbuchen spoke at a media teleconference March 27, announced less than 24 hours earlier, to dispense the latest dose of bad news for the mission. JWST, whose launch had already slipped last year from October 2018 to between March and June 2019, would be delayed again, now until approximately May 2020. The delay has obvious implications for the mission, and the scientists who have been waiting for years to use the telescope. However, it could have repercussions that go far beyond this single mission.
Human error and optimistic schedules
There was no single technical issue that caused this latest schedule slip. “The change in launch timing is not indicative of hardware or technical performance concerns,” Zurbuchen said on the call. “Rather, the integration of the various spacecraft elements is taking longer than expected.”
That work suffered a number of problems involving the spacecraft and sunshield, rather than the telescope and instruments. When NASA delayed JWST’s launch last year, it cited issues with thrusters on the spacecraft and delays with the testing of the five-layer deployable sunshield. Both those issues factored into the new, longer delay.
The biggest problem, said Dennis Andrucyk, deputy associate administrator for science at NASA, was with the spacecraft’s thrusters. “The propulsion system’s issues were all introduced by human error, unfortunately,” he said in a briefing at the National Academies’ Space Science Week meeting just a couple hours after the official announcement of the delay. Technicians cleaned the thrusters with an “incorrect solvent,” he said, damaging seals in valves. They had to be refurbished, causing a slip of about nine months.
In addition, pressure transducers in the propulsion system were damaged when workers applied the wrong voltage to them, requiring them to be replaced, at a cost of three months. A similar voltage problem damaged a heater for a catalyst bed used for a thruster, causing another month of delays.
The sunshield suffered different problems. “It took much longer to deploy, fold and stow the sunshield,” Andrucyk said. Original plans called for deploying the sunshield in a week and folding it back up in a month.“That was an optimistic schedule,” he said, noting it actually took twice as long.
Moreover, the sunshield experienced several tears during that deployment test, the largest of which was about 10 centimeters long. Andrucyk said those tears have been repaired, and steps have been taken to reduce the slack in cables used to deploy the sunshield that contributed to the problem. The sunshield work caused about seven months of delays, although some of that was in parallel with the thruster work.
A third issue, he said, was that the integration and testing schedule of the spacecraft and sunshield needed to be stretched out to take into account lessons from past work. That added three months to the schedule, and the project tacked on another three months of schedule reserve. The result, he said, was an 18-month delay to about May 2020 from the October 2018 launch date that the mission had been holding until last fall.
Webb’s exact launch date, though, remains unclear. The mission’s standing review board, whose schedule assessment led to the announcement of this delay, offered the May 2020 date at the 70 percent confidence level. “We need to reach a higher confidence level before we make a final launch date determination,” Zurbuchen said.
To assist in that work, NASA announced the formation of an independent review board, to be chaired by Tom Young, a former NASA center director and aerospace executive with extensive experience on space projects and a willingness to speak his mind. (When the delay was announced, Young, who serves on the National Academies’ Committee on Astronomy and Astrophysics, was grilling other NASA officials about the status of JWST’s already imperiled successor, the Wide-Field Infrared Survey Telescope, or WFIRST, mission.)
“The reason I’m asking for an independent review to look at this is that, frankly, I don’t think I have a concise answer to how we ended up there,” Zurbuchen said. “There are a lot of symptoms out there, but root cause is different than a description of symptoms.”
That independent review was scheduled to start in early April and wrap up at the end of May. Its results will be incorporated into continued internal analysis of the state of the project, with a report to Congress by late June that will include a revised launch date and development cost.
Even as those reviews continue, NASA announced several managerial changes to the program. Those include more interaction between agency leadership and executives at Northrop Grumman, as well as putting more senior NASA project managers on site at Northrop’s facility. The company also established a direct reporting line between its JWST project manager, Scott Willoughby, and company president Kathy Warden.
In the days following the announcement of the delay, NASA shuffled some project leadership. Eric Smith, who served as JWST director at NASA Headquarters, was moved to the position of program scientist. Greg Robinson, deputy associate administrator for programs in NASA’s science mission directorate, took over as program director.
Three ways to measure costs
Perhaps the biggest question facing JWST is what effect these delays, and the work to overcome them, will have on the mission’s cost. In the 2011 “re-plan” of JWST, when cost and schedule overruns threatened the mission with cancellation, Congress set a $8 billion cap on its development. The mission has remained within that cost cap — at least for now.
While JWST’s reviews continue through June, just how much its cost will increase isn’t known, or even if it will breach the cap, which would require Congress to formally reauthorize the mission. “We think it’s likely that we will, but we don’t have the data in hand to establish a new cost,” explained Paul Hertz, director of NASA’s astrophysics division, at a meeting of the Committee on Astronomy and Astrophysics the day after the announcement. “We’re not 100-percent confident that we’re going to breach that $8 billion.”
The implications of a cost increase on JWST are complex and depend on the timescale you examine. “There are three different costs at play here,” Hertz said, from the short to the long term.
One cost, he explained, is simply how much money the mission needs in any given year. “What matters to me as the astrophysics division director is, is the money I need in any given year more than the money that is currently budgeted for Webb?”
Hertz said that, for fiscal years 2019 and 2020, money that had been budgeted for operations could instead be spent on development. As a result, he did not expect to need much additional funding to accommodate the Webb delay. “I don’t believe it will be a large impact,” he said, and not until 2020. “The amount of money we need in [fiscal year 2020] will be modest compared to the whole astrophysics budget.”
However, a shift of funds from operations to development — NASA requested $305 million for JWST in its 2019 budget proposal and expected to need nearly $200 million in 2020 — would count against that $8 billion cost cap, the second of Hertz’s costs. Whether the mission breaches the cost cap, and by how much, won’t be known until June.
The third cost is the mission’s total life-cycle cost, including its development and operations. That will go up, he said, because operations will extend at least 18 months longer than previously planned. While JWST has a prime mission of five years, Hertz said planning assumes that it will be extended to perhaps 10 years or more “just in case it passes senior review” — a line met with laughter by a roomful of astronomers who have long assumed that NASA will operate the telescope as long as it’s technically feasible to do so.
With such an extension, Hertz said expects JWST to be operating into the 2030s, assuming it enters operations in late 2020 or 2021. That will put its operations in parallel for years with NASA’s next astrophysics flagship mission, WFIRST — if it gets built.
NASA’s 2019 budget proposal sought to cancel WFIRST, citing a desire to use at least some of funding projected for WFIRST for exploration programs. However, Congress provided WFIRST with $150 million in the fiscal year 2018 omnibus bill, more than requested, and included report language indirectly criticizing any proposal to cancel it.
That windfall, though, came before the new JWST delay, leaving some fearing that Congress may not be in such a generous mood when it takes up the 2019 budget proposal. Zurbuchen went to great lengths in presentations to clarify that the sins of JWST are not also the sins of WFIRST.
“There’s going to be an impact of perception,” he said, acknowledging recent efforts to reduce the costs of WFIRST. The difference, he emphasized, was that WFIRST relies little on new technologies: its telescope is a hand-me-down from the National Reconnaissance Office, and its main instrument is more mature than JWST’s instruments were at a similar phase of development.
“WFIRST and Webb are as similar to each other as the Malibu that I drive and the Ferrari my neighbor drives,” he said. “They’re both cars, but they’re really different classes of both cost and complexity.”
The delay in JWST could also affect planning for later missions beyond WFIRST. Astronomers had hoped JWST would be operational in 2019 so that initial science results could influence the next astrophysics decadal survey, scheduled to be completed in late 2020. That survey will identify, among other things, the top-priority flagship mission that would be in line for NASA to develop and launch some time in the 2030s.
“We recognize that the timing of the decadal is a multi-stakeholder type of discussion,” Zurbuchen said, suggesting “we should flip planetary and astrophysics and move astrophysics to the right.” With the next planetary science decadal scheduled to be completed in 2022, this would likely delay the astrophysics decadal to perhaps 2024.
For now, the community shows little sign of supporting such a delay. “I would as soon just not delay it a couple of years,” said Anne Kinney, head of the NSF’s mathematics and physics sciences directorate. NSF is involved with the decadal as it funds ground-based observatories. “From NSF’s perspective, let’s keep going.”
“We’re still holding discussions both internally and with NASA and NSF as to what the astronomers should do,” said David Smith of the National Academies at an April 4 meeting of a NASA Mars advisory committee. “My hope is that we stick to the schedule.”
The delay and additional expense is worth it for both JWST and future missions, Zurbuchen emphasized. “The stupidest thing we could is to somehow rush to a deadline,” he said. “What’s really important here is that when we’re done, we launch this and we have a telescope on orbit that works and fulfills on its promise.”
He added that a lesson that should not be taken away from JWST’s woes is that NASA should avoid complex missions like it. “We should push the envelope,” he said. “But what we should also do is not make stupid mistakes.”