WASHINGTON — While NASA has resumed some work on the James Webb Space Telescope, project officials say even that limited level of activity will soon come to a halt because of the coronavirus pandemic.

NASA announced March 20 that it suspended work on the space telescope, which had been undergoing integration and testing, or I&T, activities at a Northrop Grumman facility in Southern California. That decision was made “to ensure the safety of the workforce,” NASA said in a statement.

However, the project announced March 25 that it had decided to resume some work “with reduced personnel and shifts” through early April. “We’ll assess and adjust decisions as the situation unfolds,” the project tweeted.

That work is continuing with only a small fraction of the NASA personnel usually present. “We were running about 45, sometimes 50 people out there on a weekly basis. We’re down to 15 now,” said Bill Ochs, JWST project manager at NASA’s Goddard Space Flight Center, during a March 31 online meeting of the National Academies’ Committee on Astronomy and Astrophysics.

“We are doing some I&T activities, but it’s not at the rate that we had been doing them,” he said of current work. What work is taking place is being carefully evaluated to make sure it’s safe, he said, including changes like new cleanroom procedures to maintain distance between personnel and limiting the number of the people in the “gowning area” at any one time preparing to go into the cleanroom.

That reduced level of work will continue until just before a test of the Deployable Tower Assembly, a core structure that supports the spacecraft and telescope sections of JWST, scheduled for early April. “At that point we will shut down I&T operations,” Ochs said. “Activities from that point forward require the full NASA and Northrop team.” Some of those activities, he added, will also require personnel from international partners contributing instruments to the telescope.

The effects of the coronavirus pandemic on the project extend beyond activities at Northrop Grumman. Goddard is at Stage 4 of NASA’s response framework, closing the center to all but the most essential personnel and halting travel. “We have an exception for JWST, but we have taken a very conservative approach,” he said. The Space Telescope Science Institute, which handles science operations, is closed through at least April 10.

Before the onset of the pandemic, the project had been making good progress preparing the telescope for a launch still scheduled for March 2021. That included the replacement of a command and telemetry processor and traveling wave tube amplifiers on the spacecraft in January, replacing components that failed in earlier tests. The telescope also deployed its primary mirror in a test in early March.

Ochs said that, before the slowdown in work on JWST, the project had 52 days of schedule reserve remaining. How much of a delay the pandemic might cause in its launch won’t be clear until after the pandemic ends. “Once we hit the other side of this, we will then do a full evaluation of where we are with the JWST schedule,” he said.

JWST’s current budget could handle a launch delay of a few months without additional costs, he added. “We can probably go months past at this point, at least a few months,” he said. “But if we go beyond that, then you would have an issue with money.”