On Sunday morning, somewhere above the Utah desert, a parachute will open and a capsule containing about 250g of rubble will float to the ground. As it descends, four helicopters bearing scientists, engineers and military safety personnel will race across the arid landscape to recover the precious cargo.
Because this is not just any old dirt: these are 4.6bn-year-old chunks of space rock that could not only shed light on how planets formed but how life itself began.
