At such close proximity, the electrons in the photovoltaic cell were being liberated by the electric field generated by the hot object, but the usual process of generating a current was going awry.

They are powered by laser beams on the ground firing at photovoltaic cells on the vehicles – like those used in solar panels – in a process called “power beaming”.

"What we've demonstrated is a new physical process that is not based on standard photovoltaic mechanisms, but can give you a photovoltaic-like response at very high temperatures," Melosh said.