Russia’s Proton rocket crashed less than a minute after its liftoff from Baikonur, Kazakhstan on July 2, 2013. The rocket started veering off course right after leaving the pad, deviating from the vertical path in various directions and then plunged to the ground seconds later nose first. The payload section and the upper stage were sheered off the vehicle moments before it impacted the ground and exploded.
By July 9, it is transpired that investigators sifting through the wreckage of the doomed rocket had found critical angular velocity sensors, DUS, installed upside down. Each of those sensors had an arrow that was suppose to point toward the top of the vehicle, however multiple sensors on the failed rocket were pointing downward instead. As a result, the flight control system was receiving wrong information about the position of the rocket and tried to “correct” it, causing the vehicle to swing wildly and, ultimately, crash. The paper trail led to a young technician responsible for the wrong assembly of the hardware, but also raised serious issues of quality control at the Proton’s manufacturing plant, at the rocket’s testing facility and at the assembly building in Baikonur. It appeared that no visual control of the faulty installation had been conducted, while electrical checks could not detect the problem since all circuits had been working correctly.