Solar panel cleaning method goes intergalactic – as NASA investigates airflow cleaning of its Mars rovers

The idea of life on Mars has mesmerized mankind for centuries. Much remains to be discovered, but it’s an established fact that the atmosphere on Mars gradually coats solar panels in dust and reduces efficiency, just as happens here on earth. (photo: NASA/JPL-Caltech)

Previously, NASA had four roving vehicles – among them ‘Opportunity’ and ‘Spirit’ – that have been exploring sand dunes and sedimentary rock on Mars since 2004. Though originally designed to fulfil a 90-day mission, the solar powered vehicles have beaten all expectations as to the duration of their working life – Spirit eventually stopped working in 2010 when its solar panels became covered in dust, and so did Opportunity, in 2019.

Martian wind can both soil or remove dirt on rovers (photo: NASA/JPL-Caltech)

The vehicle’s future was uncertain for long: The same winds that have blown away dust from the solar panels would cover them again, as Mars experienced unprecedented dust storms. In February of this year, a fifth rover – ‘Perseverance’ – landed successfully on Mars. Unlike its predecessors, it brought a small helicopter, called ‘Ingenuity’ (header image). Whilst the helicopter is solar powered,  the rover is driven by a radioisotope battery instead.

Even without epic Martian dust storms, a previous 90-day mission by the ‘Sojourner’ rover saw its power output reduced by 23% by the mission’s end. Similarly, accumulating dust here on earth reduces solar panel energy production – after one month by up to a third in arid regions like the Middle East, unless they are expensively maintained.

Photograph of Mars without and with the sandstorm. (photo: NASA)

A Mars rover can be angled to ‘catch’ surface winds and blow accumulated dust away, but earth’s solar farm panels are fixed in place. ‘Aerial Power’ envisions to bring the cleaning wind to solar panels. It has developed cleaning drones that detect the solar panels. The highly accurate self-flying drones create down-draft over these – row by row. The downward airflow bows away soiling such as dust.

Aerial Power also targets sun-rich arid regions of the world. Solar power production is booming in these areas, but the cleaning costs are high and logistically challenging. Hence tests were conducted in India’s Rajasthan desert.

Monitoring of solar panels in the Rajasthan desert (photo: Aerial Power)

“The aim of Aerial Power is to reduce operation and maintenance costs for solar panels, and therefore raise panel profitability to allow for solar farms to be established in more marginal areas. With these cleaning drones we anticipate being able to significantly reduce the frequency of any manual wet cleans” the inventor and founder Ridha Azaiz explains.

The US Patent and Trademark Office – finding the cleaning method novel – granted patent No. US 10,046,857 as well as did the China National Intellectual Property Administration, recently (CN 106537274). This is in addition to the previous granting of European (EP 3077882) and Australian (AU 2015285989) patents.