The European Space Agency is putting four of its space missions into “safe configurations” amid the novel coronavirus pandemic as the agency plans to reduce the number of people who can come into ESA’s primary mission control center in Germany. The instruments on these spacecraft will be turned off, and the vehicles will go “largely unattended” as they travel throughout the Solar System, according to ESA.

“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, ESA’s director of operations, said in a statement.

“Our priority is the health of our workforce.”

Of the missions going dark, two include vehicles orbiting Mars — the ExoMars Trace Gas Orbiter and Mars Express — which both take measurements of the Red Planet’s atmosphere. A mission called Cluster is also going quiet, which includes four spacecraft currently in orbit around Earth that study how particles coming from the Sun interact with our planet’s magnetic field. ESA’s Solar Orbiter mission, which just launched in February to study the Sun’s poles, is also powering down its instruments.

Most ESA employees have been working from home for the last two weeks, but the agency decided to heighten restrictions at its European Space Operations Center in Darmstadt, Germany, after an employee working there tested positive for COVID-19. Local, state, and national governments in Europe have also implemented tighter restrictions across the continent, which factored into ESA’s decision.

The agency maintains that these spacecraft are all in stable orbits and will be safe while in these new configurations. “These probes are designed to safely sustain long periods with limited or no interaction with ground, required for instance for the periods they spend behind the Sun as seen from Earth, when no radio contact is possible for weeks,” Densing adds. “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.”

In the meantime, the personnel who are still allowed at mission control will focus on maintaining ESA’s other spacecraft throughout the Solar System, including the BepiColombo vehicle on its way to Mercury. That spacecraft is scheduled to do a flyby of Earth in April, and ESA says only a “very small number of engineers” will be on hand to perform the maneuver. They’ll also be sure to maintain proper social distancing while in mission control.

These aren’t the first European space missions to experience delays and setbacks because of the novel coronavirus pandemic. The launch of ESA’s Rosalind Franklin Mars rover was delayed to 2022, in part because of travel restrictions that are being imposed throughout Europe. And launches out of Europe’s primary spaceport in French Guiana have been suspended indefinitely until the pandemic subsides.