The ‘wings’ of the Orion ship are ‘vital’ solar panels for Artemis I

If the Apollo missions used fuel cells for the supply of energy, each Orion vehicle will use a set of four solar panels supplied by the European company Leonardo. Alessandro Fumagalli, head of space engineering at Leonardo, and Arnaud de Jong, director of the Airbus solar panels team in the Netherlands, explain to us the particularities of these panels and why it will be necessary to monitor them throughout of the mission.

After its launch by the powerful SLS launch vehicle, NASA’s Orion vehicle flies towards the Moon for a mission lasting more than 25 days. His return to Earth is scheduled for December 11.

To function throughout its mission, Orion will need a power source. This electricity will be supplied by four solar panels located on the service module, unlike the Apollo missions whose energy production was based on fuel cells “. This is explained to us by Alessandro Fumagalli, space engineering manager at Leonardo in charge of their production. Leonardo also supplied the Control and Power Distribution Units (PCDUs) which allow the control and distribution of energy to the spacecraft. Admittedly, this element may not be the “sexiest” of all the vehicle’s subsystems, but it is ” very particular and critical for the proper functioning of Orion “. He controls ” the energy generated by the solar panels and distributes it to the battery and to all the equipment of Orion for their operation. Like the heart pumps blood in the human body, the PCDU pumps electricity in the spacecraft: it’s not sexy, it’s vital “.

These panels are installed on the service module of Orion. They were launched in a folded position, “ held in place by a specific locking mechanism that ensures the safety of the system during launch “. Once in orbit, the locking mechanisms are released and the four solar panels unfold in an X configuration, very characteristic of rectangular panels. We find this configuration in X on the automatic transfer vehicle ATV of ESA, whose solar panels were provided by Leonardo. As a reminder, at the origin of the Orion program, NASA was considering round solar panels.

Artemis I: stunning photos of Earth taken by the Orion spacecraft en route to the Moon

With a total mass of more than 260 kilos, these solar panels, also called “wings”, are seven meters long. They are each composed of four branches with three photovoltaic panels (PVA) each comprising 1,242 cells based on gallium arsenide “. In total, these some 15,000 cells will provide the Orion Service Module with 11.1 kW of power for its mission “. It is interesting to note that thanks to the technological advancements made since the days of the ATV’s design, the solar cells used will provide more than double the power of the ATV’s solar panels, yet of similar size “.

Solar panels with a much more complex design than it seems

To those who think that the design of Orion’s solar panels is actually quite simple, well think again! As Arnaud de Jong, director of the Airbus solar panel team in Leiden, the Netherlands, for a manned mission to the Moon points out, the requirements in the design and development of solar panels are complex “. In order to limit the stresses exerted on the panels during the launch into lunar orbit and during the return to Earth, the ” branches must be able to tilt 60 degrees, both forward and backward. This broad movement involves designing branches made up of thin solar panels reinforced with hinges and pendulums “. Concretely, during the translunar injection manoeuvre, ” the end of the branches will move over a distance of 1.06 meters “. A risk taken very seriously and closely monitored. Each of them is “ equipped with a camera oriented towards the Orion capsule in order to monitor this movement with precision “.

Another point of vigilance, and not the least, although its solar panels are designed to avoid resonances with the motors of the service module, the panels have a certain resonance frequency. However, the motors of the service module are pulsed at a certain frequency in order to be able to control the direction and the attitude. Checking for these frequency interferences to ensure that the panels do not resonate, which could cause them to fall apart, is one of the objectives of this test flight.

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