WASHINGTON — Massive cost growth on NASA’s James Webb Space Telescope (JWST) will imperil funding for the agency’s on-orbit astronomy missions while potentially wiping out big-ticket space observatories and a host of less-expensive development projects deemed high priorities by the science community, according to experts.

During a Nov. 10 news conference, NASA released the findings of an independent review that found the JWST will cost some $1.5 billion more than its current $5 billion life-cycle cost estimate, and that the observatory’s launch, previously slated for June 2014, will not occur before September 2015. Led by John Casani of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., the Independent Comprehensive Review Panel attributed JWST cost growth to poor management and inadequate funding reserves needed to develop, launch and operate the next-generation flagship astronomy mission.

Alan Stern, a former associate administrator for NASA’s Science Mission Directorate, said the cost growth could ravage the agency’s $1.1 billion annual astrophysics budget, 40 percent of which is already consumed by JWST development.

“Are we going to turn off all the many existing astrophysics satellites and kill the support to analyze the data from them and stop building anything else, just so JWST can continue to overrun?” Stern said. “That’s the question that the astrophysics community has to ask of itself, and that NASA should be asking.”

According to the independent review panel, Congress will need to add about $250 million to NASA’s $444 million request for the JWST in 2011 alone just to maintain the newly projected 2015 launch date. Another $250 million will be needed in 2012, in addition to the agency’s current projection of $380 million for the program in that year.

“Even at the best case, the $1.5 billion upper will virtually wipe out the inspirations of the newly released decadal survey in astrophysics for 2010-2020,” said Stern, who currently is associate vice president of the Southwest Research Institute’s Space Science and Engineering Division in Boulder, Colo.

Stern was referring to the National Research Council report, released Aug. 13, that laid out the science community’s top priorities in astrophysics research for the next decade. Formally titled “New Worlds, New Horizons in Astronomy and Astrophysics,” the survey designated the $1.6 billion Wide-Field Infrared Survey Telescope as the top priority for large missions and also recommended that NASA continue to spend about $100 million per year on more modestly priced missions.

Stanford University professor Roger Blandford, who chaired the decadal survey panel, said the new cost and schedule estimates for the JWST could be devastating to current and future programs.

“Clearly it’s going to have a severe impact on the current program, let alone the recommended one,” Blandford said in a Nov. 11 interview, adding that his committee worked hard to develop an affordable and exciting program in its survey.

Blandford said scientists participating in the decadal survey were told to assume NASA’s astrophysics budget would remain flat or decline slightly in the decade ahead. The panel also took into consideration the strain that additional JWST delays would impose on the astrophysics budget, he said.

“We put a lot of effort into those cost estimates,” he said. “Obviously it’s extremely disappointing to many people to learn that these management problems have led to severe cost overruns and delays.”

NASA Administrator Charles Bolden took responsibility for the mismanagement that led to the cost overruns but said NASA needs time to implement changes to program oversight before it can determine whether more money or time will be needed.

“I’ve put a change in the management structure in place, and we’ve got to take some time to see if that works, and I’m confident it will,” Bolden told reporters Nov. 12. “So I don’t talk about funds or schedule, and I see no reason to change any of those before we look at what impact the change in management has had.”

Led by NASA’s Goddard Space Flight Center in Greenbelt, Md., the JWST is an infrared telescope with a 6.5-meter foldable mirror and a deployable sunshield the size of a tennis court. Northrop Grumman Aerospace Systems of Redondo Beach, Calif., is prime contractor. An Ariane 5 rocket provided by the European Space Agency is slated to launch the observatory to the second Lagrange point — a gravitationally stable spot 1.5 million kilometers from Earth.

NASA has spent about $3 billion to date on the JWST program, which was conceived in 1996 as the successor to the agency’s flagship Hubble Space Telescope. By the time Northrop Grumman was awarded the prime contract to build the observatory in 2002, the estimated program cost was $2 billion.

With 14 space telescopes on orbit and several more in development, NASA’s budget for starting astrophysics missions was already stretched before the new JWST cost estimates were released.

According to the independent review panel’s report, it will cost $1.9 billion over the next five or so years to finish building and launch the observatory, or about $1.4 billion more than previously anticipated. NASA has budgeted about $600 million to operate the JWST over the following five years.

U.S. Sen. Barbara Mikulski (D-Md.), who called for the independent review in June to identify the root causes of cost growth and schedule delays on the JWST, expressed dismay over the panel’s findings and warned NASA that it cannot let the telescope’s scientific potential override the need to rein in costs.

“We cannot afford to continue with business as usual in this stark fiscal situation,” she wrote in a Nov. 10 letter to Bolden after reading the Oct. 29 report.

Although Casani’s review took issue with budget and management of the program, it characterized the JWST’s technical progress as “commendable and often excellent.”

The panel recommends restructuring the JWST project office at Goddard to emphasize cost and schedule ceilings. “The flawed practice by the Project of not adequately accounting for threats in the budgeting process needs immediate correction,” the report states.

However, the report also found that “the JWST Project has invested funds wisely in advancing the necessary technologies and reducing technical risk such that the funds invested to date have not been wasted. The management approach, however, needs to change to focus on overall life cycle cost and a well-defined launch date.”

Bolden, in a Nov. 10 statement, said he agrees with the panel’s findings.

“No one is more concerned about the situation we find ourselves in than I am, and that is why I am reorganizing the JWST Project at Headquarters and the Goddard Space Flight Center, and assigning a new senior manager at Headquarters to lead this important effort,” Bolden said.

The NASA chief said he is encouraged by the panel’s finding that the JWST is technically sound and continues to meet its milestones.

“However, I am disappointed we have not maintained the level of cost control we strive to achieve — something the American taxpayer deserves in all of our projects,” he said. “NASA is committed to finding a sustainable path forward for the program based on realistic cost and schedule assessments.”

Northrop Grumman spokesman Lon Rains said the JWST is an outstanding example of NASA’s national and international leadership, and will yield unprecedented advances in our understanding of the universe. He said the company is pleased that the independent review panel found JWST to be technically sound and that its design and integrity were not questioned.

“We will continue to work closely with NASA and our partners to deliver this important science mission at the lowest possible cost, and earliest schedule,” Rains said.