Solar winner uses lunar science

The Solar Challenge was a race for cars that are powered only by sunlight. The car completed the 3010 kilometres in 30 hours and 54 minutes - a record for the event.

The vehicle used technology that came straight out of ESA's Space Science programme. Its aerodynamically shaped outer shell is made of space-age plastics to keep it light and strong. The main body and mudguards are reinforced with aramide, better known as Twaron. This material is used on satellites as protection for micrometeorite impacts, and nowadays also in high-performance equipment like bulletproof vests.

The car’s shell is covered with the triple junction gallium-arsenide solar cells, also developed for satellites. These cells produce up to 20% more energy than those used in a previous race in 2001. Cells like these are being used in the solar panels which help to power ESA’s technology-demonstrating SMART-1 mission, launched to the Moon in September 2003.

Nuna II is also using the same type of batteries as flown on board SMART-1. These highly efficient batteries are used by SMART-1 when out of contact with the Sun and were originally developed for space applications where reliability is essential. Nuna ran on these batteries very cloudy conditions, which were charged up by the solar cells in sunny weather.

Another interesting feature of Nuna II is that it used ten devices known as ‘maximum power point trackers’ (MPPTs). These were developed by ESA to optimise the output of spacecraft solar panels, even when they are in the shade. ESA’s upcoming comet-chaser mission Rosetta will be using MPPTs to get the most energy out of the Sun’s light during its ten-year journey to Comet 67P/Churyumov-Gerasimenko.

The new technologies used in Nuna, originally developed for spacecraft travelling to other worlds, may find application in the designs of future transport systems and, ultimately, could have benefits to industry and our daily lives here on Earth.