When NASA’s first rover set down on the surface of Mars in 1997, its streamed colour images caused an early internet sensation. After centuries of dreaming, here we were, at eye level to our closest potentially habitable neighbour, and the sight was as bleakly majestic as we could have imagined: a rocky, red desertscape on a scale entirely alien to Earth. One mountain, Olympus Mons, was the largest in our solar system (three times the height of Everest, with a footprint the size of Sweden); dune-seas swept its northern hemisphere while 7km-deep canyons veined the south.

Watching on a clunky desktop computer in the Dutch university town of Twente, 20-year-old Bas Lansdorp’s first thought was one of wonder; his second of longing (“I want to go there!”), then the melancholy realisation that, being Dutch, he could never fly with NASA. So he’d have to do it himself.