Instead of $8.8 billion, the total lifetime cost of the telescope—which includes development, launch, and five years of operation—would come to $9.66 billion, officials said. The new total meant that Webb had breached a cap set by Congress in 2011, when lawmakers had begun to worry in earnest about the mission’s ballooning costs. Now if Webb wants to leave Earth, it needs Congress to approve an extra $800 million for the mission.

Webb is expected to get the money. Even the stingiest politicians recognize that you can’t cancel a mission that has already swallowed more than $8 billion in taxpayer dollars. But lawmakers aren’t thrilled, and some of them are wondering whether it shouldn’t be their constituents who pick up the tab. Maybe, they say, it should be the spacecraft manufacturer that has contributed to most of these delays: Northrop Grumman, a longtime NASA contractor.

“It is clear that Northrop Grumman did not adhere to the best business practices,” said Lamar Smith, the chair of the House Committee on Science, Space, and Technology, at a hearing on Friday, addressing Northrop Grumman’s CEO, Wes Bush. “When government contractors make mistakes, typically no one is held accountable. The mistakes just happened, or were unavoidable, or won’t happen again. But in every case, the American people pick up the bill.”

Northrop Grumman is in charge of building and testing Webb’s sun shield and spacecraft elements. For a project as complex and pioneering as Webb, errors are to be expected. But the errors made under Northrop Grumman’s watch were avoidable, according to independent reviews. Workers used the wrong solvent to clean the observatory’s propulsion valves. A wiring error severely damaged the spacecraft’s pressure transducers. During an important test, the fasteners designed to hold the sun shield together came loose, scattering dozens of bolts that took months to find

These mistakes alone resulted in a schedule delay of about 1.5 years and $600 million. Northrop Grumman will spend the summer recovering from these errors, under increased oversight from NASA.

Northrop Grumman has a so-called cost-plus contract with NASA for Webb, which means the space agency assumes the risk of overruns. (Such contracts are the norm for large, unproven engineering projects, which are more likely to experience cost overruns. Fixed-cost contracts, in which the contractor assumes the risk, are less desirable for contractors.) Whenever Webb has needed more cash, NASA has coughed up the money, sometimes rerouting it from other missions inside the agency.

Bush said Northrop Grumman is willing to make any profit the company earns from Webb contingent on the successful deployment and operation of the telescope in 2021. But perhaps, Smith said, given Northrop Grumman’s performance, it’s time for the company to pitch in.