The Northern Territory's most ardent UFO-spotters may well be scratching their heads as what looks like a convoy of extra-terrestrial vehicles sets off on a race through the outback.
On Sunday the World Solar Challenge will take off for another year as 40 teams of young engineers compete to see which car is most energy-efficient, with sometimes outlandish results.
With no more than six square metres of solar panels, engineering students from universities around the world are combining car technology with energy-efficient alternatives to conventional engines.
From Sunday, they'll be racing 3000km down the guts of the country from Darwin to Adelaide, a trip not for the faint-hearted.
"It's not a car to drive for fun," Koen Sedee from Dutch Solar Team Twente says of the heat.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Drivers in his team underwent endurance training with the Royal Air Force in the Netherlands, and have spent the past few weeks in Darwin fine-tuning their condition.
The Red Engine car, shaped like an aeroplane wing, weighs a mere 139kg, which is 40kg lighter than their last effort even though engineers have added a fourth wheel.
"The driver sits in the middle and it's much more stable," Mr Sedee says.
"It looks like a bigger car but aerodynamically it's just better, we think."
The Red Engine will race in the Challenger class in a single stage to Adelaide, with teams driving as far as they can until 5pm each day, when they will have to make camp in the desert.
But Stefan Spychalski, from German team Hochschule Bochum, scoffs at the high-speed cars, calling them "table tennis cars" due to their flat design.
His team's 2009 effort inspired a new category in this year's race: the Cruiser Class, which aims to build cars that would meet road registration requirements.
"We decided to build cars not for racing but for everyday life," he says.
In 2009 his team knew the car would be too slow to win, but now that it has its own class, the pressure to win is on.
Their Powercore Suncruiser generally travels at about 60km per hour, but can reach up to 100km per hour.
"Actions like overtaking, speeding, driving fast, are totally unusual for a solar car driver. You use so much energy with those actions, so we don't do that," he says.
"The endurance of the car is important - you must travel at a velocity that matches your energy consumption."
The student designers of the 320kg vehicle (which Mr Spychalski fears is too heavy) looked to car brands such as Audi, Volkswagen and BMW to develop their solar car, keeping in line with their desire to create something motorists would be able to use.
"The back is a little like an Audi TT - it's looking quite good," he says.
The driver sits in the middle, so the car can be driven in both Australia and Europe, with two passengers behind on either side.
And although Sunday's race is yet to begin, designers are already looking to the future for their next car.
"We build a car every two years, and this is our fifth car," Mr Spychalski says.
"We (have) the design for the new car for 2015 already on our computers."
