WASHINGTON — The European Space Agency announced March 24 it is suspending regular operations of four of its missions, including one recently launched spacecraft, to reduce staffing needs during the coronavirus pandemic.

ESA said in a statement it was putting into a “temporary standby” mode the four-satellite Cluster space science mission in Earth orbit, the Solar Orbiter spacecraft, the ExoMars Trace Gas Orbiter and Mars Express orbiter. All four will go into a safe mode, suspending science operations.

The agency made the decision in order to reduce staffing requirements at the European Space Operations Centre in Darmstadt, Germany, in response to the pandemic. That center operates 15 missions, including the four whose operations are being suspended.

“Our priority is the health of our workforce, and we will therefore reduce activity on some of our scientific missions, especially on interplanetary spacecraft, which currently require the highest number of personnel on site,” Rolf Densing, director of operations at ESA, said in the statement.

He described the four missions whose operations are being suspended as ones in stable orbits and with long-duration missions, “so turning off their science instruments and placing them into a largely unattended safe configuration for a certain period will have a negligible impact on their overall mission performance.”

The missions vary widely in age. The four Cluster satellites, which study the Earth’s magnetosphere, were launched by two Soyuz rockets in 2000. Solar Orbiter, by contrast, launched Feb. 9 on an Atlas 5 rocket and is still in the early phases of commissioning its instruments.

Suspending operations of the four missions will also allow ESA to devote its limited staff to other missions, including the BepiColombo mission to Mercury. That spacecraft will make a gravity-assist flyby of Earth April 10 to adjust its trajectory towards the innermost planet. ESA said operations of the spacecraft during that critical flyby will be done by “a very small number of engineers and in full respect of social distancing and other health and hygiene measures required by the current situation.”

ESA said how long the operations of the four missions are suspended will depend on the pandemic. “We are confident that with very limited and infrequent interactions with ground control the missions can safely remain in that operation mode for months, should the duration of the coronavirus mitigation measures require it,” Paolo Ferri, responsible for mission operations at ESA, said in the statement.

NASA has not made similar moves with its larger portfolio of missions. Agency officials have emphasized that current science mission operations remain a high priority, even as it curtails work on other programs in development, like the James Webb Space Telescope.

“NASA also is supporting mission-essential operations for all spacecraft,” the agency said in a March 20 update regarding its response to the pandemic. That included not just the agency’s missions but also those that support other agencies, like NOAA.

“Our orbiting assets, of course, have a very high priority,” Thomas Zurbuchen, NASA associate administrator for science, said in a March 20 online town hall meeting. Those missions, he said, have few concerns about “hands-on” work that would be restricted by health precautions.