March 28, 2024

Protecting Mars Express during coronavirus outbreak

In reaction to the Covid-19 outbreak, individuals around the world are being asked to work from house where possible in order to restrict personal contact and lower the additional spread of the infection.
As of Monday 16 March, the majority of staff and contractors operating at ESA mission control began doing just this.
But what ramifications does this have for the 17-year-old Mars Express spacecraft, currnently in orbit around the Red Planet?

Launched in June 2003, Mars Express became ESAs first-ever visit to another world in the Solar System

For many objectives it is possible, if required, to put the spacecraft into Safe Mode, where it is parked in a steady position with all non-essential systems turned off. For Mars Express however, a prolonged time in this mode would not be really safe at the minute.
Mars Express is currently in an eclipse season, where in every orbit the spacecraft goes through the shadow of Mars, preventing power from being created by the solar selections.
As the spacecraft enters the martian shadow, it counts on batteries to supply it with power and on internal heating systems to keep it warm. To ensure the 17-year-old batteries are not too deeply released throughout this duration, the group requires to change the heating units prior to, during and after each eclipse to keep essential spacecraft systems at the ideal temperature level to function. This activity reduces the general heating system power intake by around 30%.

MEX Credit: ESA/Alex Lutkus

Mars Express uses star trackers and gyros to identify which instructions it is pointing in. The gyros are now older and are turned off the majority of the time to maintain their remaining runtime. The software upgrade carried out in 2018 is working well and has actually made it possible to significantly increase for how long the life staying in the units can be extended out.
The gyros do require to be switched on when daily for regular upkeep activity (to dump momentum from the reaction wheels, which allow the spacecraft to change its attitude, the instructions in which it points). This isnt possible without the ability to interact with and command the objective– another reason that Safe Mode isnt an option for the old martian orbiter.

An uncommonly quiet Mars Express control space

This all requires individuals on hand to assist Mars Express back into the light. In Safe Mode, none of these commands would get on board. This means the load on the batteries would increase and most importantly the gyros would stay on, eating into their remaining lifetime.
At present, the team mores than happy to report that routine science operations are continuing through a reduced presence on site, and adjustment of the operating procedures to fit this tight spot.
In a case the group were totally unable to get on site, they have generated an emergency situation commanding timeline which prepares the spacecraft for eclipses, prevents pointing the star trackers at Mars, turns the gyros on and off as required and performs other tasks to keep the spacecraft safe
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A couple of stunning views of the Red Planet, caught by Mars Express

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This, if activated would keep the spacecraft safe for about three weeks. As each week passes the team adds another week of safety commands to the plan, so there are constantly 3 weeks worth of commands available to be sent to the spacecraft if needed.
Nevertheless, as there is minimal area on board the spacecraft to store commands, the group has needed to eliminate any commands that are not needed to keep the spacecraft safe.
Sadly, this includes the commands that would be required to operate the science instruments. Science observations would for that reason be suspended for the period if this emergency plan is activated.

As the spacecraft passes into the martian shadow, it relies on batteries to provide it with power and on internal heating systems to keep it warm. To make sure the 17-year-old batteries are not too deeply released throughout this period, the group requires to change the heating units prior to, throughout and after each eclipse to keep important spacecraft systems at the right temperature level to operate. Mars Express utilizes star trackers and gyros to determine which direction it is pointing in. This all needs people on hand to assist Mars Express back into the light. In Safe Mode, none of these commands would get on board.

Launched in June 2003, ESAs Mars Express has actually been studying all aspects of the Red Planet for more than 15 years.