On April 30 a rocket-powered sled set a speed record for a rail-mounted vehicle, travelling the length of a 5 km test track in 6·04 sec at a maximum speed of Mach 8·5, about 10300 km/h.

The Holloman High Speed Test Track in New Mexico is used by the US Missile Defense Agency for the development and testing of weapons. The rocket sled runs on narrow gauge rails to limit vibration at hypersonic speeds, and the test was designed to demonstrate improvements in rocket sled design, rail alignment, rocket propulsion and modelling and simulation.

The test sled was powered by 13 rocket motors. Each of the four stages detached as it burned out and the next stage ignited. To simulate the reduced air friction in the upper atmosphere, the rocket travelled for 3·4 km in a 4·7m diameter tube filled with helium. Near the end of the run fixing bolts were detonated, allowing the payload to separate from the sled and hit a target. ’This is the culmination of five years and $20m’, said Lt Col James Jolliffe, Commander of the 846th Test Squadron.

The previous speed record was Mach 8, set at Holloman HSTT on October 5 1982.