WASHINGTON — All the major elements of NASA’s next flagship space telescope are now under one roof as NASA says its development remains on cost and schedule.

In presentations at two advisory committee meetings last week, Mark Clampin, astrophysics director at NASA Headquarters, said the telescope assembly for the Nancy Grace Roman Space Telescope is now at the Goddard Space Flight Center, joining other components of the spacecraft there.

Clampin said the telescope unit, which recently completed thermal vacuum tests at an L3Harris facility, was flown to Goddard on a C-5 cargo aircraft earlier in the week and is now in the same building at the center used for assembly of elements of the Hubble Space Telescope and James Webb Space Telescope.

“Building 29 now hosts the whole of the Roman Space Telescope. This is a real achievement,” he said at a Nov. 8 meeting of the Committee on Astronomy and Astrophysics of the National Academies’ Space Studies Board.

Other key portions of Roman, including the spacecraft bus and its two main instruments, were already at Goddard. The arrival of the telescope assembly, he said, keeps work on the spacecraft on schedule.

Clampin, in his comments Nov. 8 to the National Academies committee, credited teams at Goddard and L3Harris for “working with us to come through on what became a pretty challenging schedule to get this telescope delivered on time and avoid us having to slip the launch date.” He didn’t elaborate on those schedule challenges.

NASA is working to a launch readiness date of no later than May 2027 for Roman and a development cost cap, set by Congress, of $3.5 billion. “This program is still on cost and schedule,” he told the National Academies committee. “We’re working to a congressional cost cap and we are staying on schedule.”

He cited an audit of the mission performed by NASA’s Office of Inspector General and published in July. “Although critical system integration, testing, and associated tasks remain, as of March 2024, Roman was meeting its cost obligations and schedule to launch by May 2027,” that audit concluded, although it noted past issues linked to the pandemic that caused an increase in lifecycle costs and a seven-month delay to its launch readiness date in 2021.

Clampin has repeatedly emphasized the importance of keeping Roman on cost and schedule, listing it as one of his top priorities in the agency’s portfolio of astrophysics programs. That emphasis on cost and schedule is intended to help build credibility about plans for future missions, like the Habitable Worlds Observatory, after the severe delays and overruns with JWST.

The one issue the audit raised about Roman was communications given “unprecedented amount of data” that the telescope will produce and the use of oversubscribed communications networks to receive it. “Roman officials have not properly evaluated risks associated with transmitting data from these oversubscribed networks and do not have a contingency plan for downlinking data should any of the networks fail,” the audit concluded.

The audit recommended that NASA evaluate the use of the Deep Space Network (DSN) for Roman as a contingency, but Clampin said at the National Academies meeting that this was not feasible. “It’s very late to be changing the design of the spacecraft,” he said, “and we don’t believe the DSN has the capability to absorb a petabyte-class mission.”

He said Roman will use NASA’s Near Space Network, including an upgraded dish that will be shared with the Lunar Reconnaissance Orbiter, as well as partnerships with Europe and Japan.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...