A group of university students who launched a weather balloon to capture images of the Grand Canyon from the edge of space thought their science experiment had failed - until a hiker found their cameras in the desert two years later.

The five Stanford University students had spent months planning their experiment before launching the helium balloon, which was carrying two cameras and a smartphone, over the desert just north of Tuba City in Arizona in June 2013.

The students, who were studying fluid lensing, had intended to retrieve the cameras and phone by using a smartphone app, which was meant to text the phone's GPS co-ordinates to the team as the equipment fell back to earth on a parachute.

But their plans were dashed when they received no communication from the phone.