Last week a Russian rocket called Proton-M exploded over a spaceport in Kazakhstan just seconds after it launched. Turns out, we can blame some dumb humans for the blast—investigators found that the rocket's angular velocity sensors had been installed upside down.

According to a report, when sifting through the wreckage, investigators discovered that these key parts—called DUS—were put into place incorrectly, even though they had arrows on them showing which way was up and which was down. The result? The flight control system was getting the wrong information about the rocket's position, and when it tried to correct, it swung out of control and exploded.

Apparently, the person culpable for the debacle was an inexperienced technician, and his work hadn't been double-checked, the report said. And even if it had launched successfully, there probably would have been more problems because the wonky DUS still haven't explained what appeared to be an engine fire when the rocket took off.

Fortunately, the only casualties were three navigation satellites; no humans on the ground were injured. But it's not the first time a Proton-M rocket has malfunctioned—it happened once in 2007 and again in 2010. So while we can't be sure if we won't see an accident again, at least one engineer has probably learned a very embarrassing lesson. [RussianSpaceWeb via AmericasSpace]