A nervous excitement hangs in the air. Half a dozen scientists sit behind computer screens, flicking between panels as they make last-minute checks. “Go and make the gun dangerous,” one of them tells a technician, who slips into an adjacent chamber. A low beep sounds. “Ready,” says the person running the test. The control room falls silent. Then, boom.
Next door, 3kg of gunpowder has compressed 1,500 litres of hydrogen to 10,000 times atmospheric pressure, launching a projectile down the 9-metre barrel of a two-stage light gas gun at a speed of 6.5km per second, about 10 times faster than a bullet from a rifle.