WASHINGTON — NASA has elevated two centers to the highest level of its pandemic response plan, halting preparations for a major test of the Space Launch System.

In a statement late March 19, NASA Administrator Jim Bridenstine announced that the Michoud Assembly Facility in New Orleans and the Stennis Space Center in Mississippi will move to “Stage 4” of its response framework for the coronavirus disease COVID-19. The Ames Research Center in California is the only other NASA facility at Stage 4, the highest level of the response plan, with the rest of the agency’s centers at Stage 3.

All work at a center effectively ends at Stage 4. While Stage 3 requires mandatory telework, it does allow personnel considered “mission-essential” to go on-site to work. Under Stage 4, even mission-essential personnel are denied access, with only those needed to “protect life and critical infrastructure” allowed at the center. All support facilities, like cafeterias and clinics, are closed, and all travel suspended.

Bridenstine said in the statement that the decision was made because of the growing number of COVID-19 cases in the community at both centers, and the diagnosis of one Stennis employee with the disease. Several other Stennis employees were in self-isolation as a precaution, he said.

In a March 18 message to Stennis staff, Rick Gilbrech, Stennis director, said the center closed the building where the employee who was diagnosed with COVID-19 worked. At the time, he said center staff were “assessing options to restore the facility to a safe working environment.”

The elevation of Michoud and Stennis to Stage 4 will strongly affect work on the Space Launch System and, to a lesser extent, the Orion spacecraft. The core stage for the first SLS mission was recently completed at Michoud, after extensive delays, and shipped to Stennis for testing leading up to a “Green Run” static-fire test later this summer.

“NASA will temporarily suspend production and testing of Space Launch System and Orion hardware,” Bridenstine said. “The NASA and contractor teams will complete an orderly shutdown that puts all hardware in a safe condition until work can resume.”

That move will delay SLS testing at Stennis for an unknown period. “We realize there will be impacts to NASA missions, but as our teams work to analyze the full picture and reduce risks we understand that our top priority is the health and safety of the NASA workforce,” Bridenstine said in the statement.