An artist's impression of the BepiColombo spacecraft flying past Earth.Credit: ESA/ATG medialab

Nearly eighteen months after it launched, the BepiColombo spacecraft is about to return to swing past Earth en route to Mercury — but the COVID-19 pandemic is causing some complications for this crucial mission milestone.

Lockdowns because of the coronavirus mean that only a skeleton staff will be on site at mission control in Germany as the fly-by happens, and those who are there will have to take extra precautions to minimize the risk of infection.

“It’s an unusual situation,” says Johannes Benkhoff, BepiColombo’s project scientist, and disappointing that team members will not be able to physically be together as they supervise the fly-by — and, they hope, celebrate its success. “But from the science and operational point of view, fortunately, we can do everything we have in mind.”

BepiColombo is a joint, €1.6-billion (US$1.7 billion) mission between the European Space Agency (ESA) and the Japan Aerospace Exploration Agency. It comprises two satellites: ESA’s Mercury Planetary Orbiter, and Japan’s Mercury Magnetospheric Orbiter.

Having launched in October 2018, the mission is on a seven-year journey to the Solar System’s innermost planet. It will be the first to orbit Mercury since NASA’s MESSENGER mission, which was there from 2011 to 2015.

To enter orbit around Mercury, BepiColombo will need to reduce its speed using gravitational tugs from fly-bys of Earth, Venus and Mercury itself. The first of these — around Earth — is due to happen on 10 April.

“To get into the inner Solar System, you need to shed energy and lose speed,” says Mark McCaughrean, senior science and exploration adviser at ESA. The fly-by, he adds, “will, basically, subtract five kilometres per second of our velocity away, which then lets us roll downhill in a safe way to Venus”.

Coronavirus challenges

Mission operations for the spacecraft are being handled at the European Space Operations Centre (ESOC) in Darmstadt, Germany. Usually, for an event such as this, there would be up to 20 members of the team present, along with dozens of other staff and members of the media. But this time, the social-distancing restrictions brought in to stop the spread of COVID-19 mean that only a handful of people can be there.

“Seven of us will be on site during the fly-by,” says Elsa Montagnon, BepiColombo’s spacecraft operations manager at ESA. This group has been split into teams of four and three, alternating in 12-hour shifts between the morning of 9 April and the afternoon of 10 April.

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The actual fly-by will take place at 04:25 ut on 10 April, with the spacecraft passing less than 13,000 kilometres from Earth. One extra person will join mission control for the hours when the craft is closest, to provide ground-station support.

The spacecraft will test out its instruments, including its cameras, as it flies past Earth, using the Moon as a calibration target. Most of the preparation for this work was done over the past few months. But staff are needed in case of a problem, to ensure that everything runs smoothly. “What is left now is to react to unexpected events,” says Montagnon.

Given the current situation, the teams on site will be taking extra care, minimizing contact during the handover period. “We have to disinfect the console to make sure we don’t propagate infection through the materials we are using,” says Montagnon. “This is very new for us.”

Precautions have already been taken with this fly-by in mind: ESA had suspended science operations on four of its missions controlled from ESOC after an employee contracted COVID-19, to ensure that at least some members of the BepiColombo team would be allowed on site.

Other staff will be monitoring the spacecraft and engaging with the rest of the team remotely. Benkhoff, who worked on preparing the instruments for the fly-by and will be involved in analysing the subsequent data, says he will be following events on a Skype call from home.

Exploring Mercury

Provided that everything runs smoothly, BepiColombo’s instruments will eventually study the surface and interior of Mercury in unprecedented detail, including making observations of the shadowed craters at its poles, where water ice is thought to reside.

“The mission is very complementary to ours,” says Andy Calloway of Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, the former mission operations manager on MESSENGER. “We mostly focused on the northern hemisphere [of Mercury]. So we’re really looking forward to getting complementary data around other parts of the planet.”

That information is still some way off. After its fly-by of Earth, the spacecraft will pass Venus twice, in October 2020 and next August, and then complete six fly-bys of Mercury, before entering orbit in December 2025.